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MuellerNick
07-07-2010, 05:22 PM
Hi!

Have to tell this:
Was at a second hand tool dealer today. Besides a bunch of this and that and 5 touching prisms (used, they need rescraping) I got a complete box of measuring wires. They are used for measuring the major diameter of threads. AKA "3 wire method".
Saw the box and asked the boss how much. "Umm, don't know. Wait ... no, price is not on the box. 20.- (about $26)". "OK, I take then". Then he asked what it is used for. :D
I really was close to pissing my pants. The set was unused. Price for a single pair is 80.- . The set is complete and has 18 pairs. Makes about 1400.-

Think I can't sleep today because of that deal.

Don't ask for the dealer, I'm in Germany and am not allowed to tell anyhow.

Nick

Forrest Addy
07-07-2010, 05:30 PM
Great score Nick. Hang on to your new wire set and will them to your progeny.

Black_Moons
07-07-2010, 06:05 PM
Nice score. What brand are they to be soo expensive?

Don't drop any :)

John Stevenson
07-07-2010, 06:17 PM
Someone has had your pants down.

Five pounds for a set.

http://www.arceurotrade.co.uk/Catalogue/Measurement/Thread-Gauges-and-Wires

.

MuellerNick
07-07-2010, 06:23 PM
No, not those ****ty Chinese chopsticks!

Here they are:
http://www.emte.ch/S-Produkte%2003.asp
Edit, set is only visible at the German page (3-Draht-Gewindemessung)

The set is at the end of the page.


Nick

John Stevenson
07-07-2010, 06:26 PM
Still work OK.

MuellerNick
07-07-2010, 06:37 PM
Still work OK

For poking around at a Bridgeport?


Nick

PeteF
07-07-2010, 06:38 PM
The set is complete and has 18 pairs. Makes about 1400.-
Excuse my ignorance but I have never used this method of measuring threads and only seen it in books. I'm assuming it's more accurate and can handle any thread that comes along? So if you're dealing with all manner of obscure threads this would be the method to use? Conversely if "standard" threads a 5 buck thread gauge is going to tell you all you need to know?

Also, Nick why are these "wires" any better than the Chinese "chopsticks"? I'm presuming they're just accurately ground rods, in which case they're either on size or not.

So many questions, so little time.

MuellerNick
07-07-2010, 06:48 PM
Well, the main differences between mine and the chopsticks are:
Mine have clips that go directly onto the shaft of the micrometer. You don't have to clue them on with seat-sour souce like the chopstiks.
Mine are cerified, the Chinese are what they are:Chinese.

Yes, you can measure any pitch (my set is from 0.17 mm IIRC to 3.2 mm). The method is described in the link.

A thread gage can't measure, it only is go for go-no go. And 5 bucks for a thread gage is an expensive whasher. ;)


Nick

PeteF
07-07-2010, 06:53 PM
You don't have to clue ....

Hey I never claimed to be Einstein but gimme a break :D

I can see how a go/no-go would be a handy attribute, even after you've finished measuring ;)

John Stevenson
07-07-2010, 06:54 PM
The main differences are Nicks are mounted in a small holder, the Chinese ones which are only copies of the Starrett ones which have served generations of machinist for years.

These you hold by wrapping an elastic band round them or a dob of blue tac.

They are just ground rods at the end of the day and provided they are the size they say, which they are, then they will work with the tables supplied for any thread and any thread angle.

There is nothing wrong with either type, they are tools at the end of the day.

Shars used to do the cheap sets in the US, don't know whether thy still do them.

.

MuellerNick
07-07-2010, 06:58 PM
Sorry, that should have been "you don't have to glue" :rolleyes:

Nick

MuellerNick
07-07-2010, 07:04 PM
They are just ground rods at the end of the day

I'd like to see how 0.17 mm "rods" look like at the end of that day.
Are they round and precise to 1 um?
I bet, the Chinese are well known for their precision and trustworthyness.


Nick

PeteF
07-07-2010, 07:09 PM
What I meant by that Nick is that it seems like any wires would be easy to measure, and they will either be on size or they won't be. If they're on size, then, as somebody who has never used the system and is simply an observer, I was having trouble seeing why a $2000 set was better than a $20 set. Besides which, so you've measured your thread to 1 um. Now what?

John Stevenson
07-07-2010, 07:15 PM
Besides which, so you've measured your thread to 1 um. Now what?
Bragging rights and dick slapping, seeing as once it crammed into a thread it's lost in the overall measurement.
Plus from the tables you have a max and min for each threads that's two bollox greater than 1 um.

PeteF
07-07-2010, 07:21 PM
Bragging rights and dick slapping, seeing as once it crammed into a thread it's lost in the overall measurement.

Well I'll have to admit I was thinking along the same lines. I've looked at this way of measuring (and Nick was right, I do have no clue) and thought that would be a good way of going about the process if you had absolutely no idea what the thread was. I guess that happens from time to time. But at the end of the day a thread isn't to hang on the wall, it needs to go in to something. I'd like to think the majority of threads are cut to some form of standard, as obscure as that may at times be, but once you've determined what the thread is, why do you need to "measure" it, let alone to 1 um? Didn't Mr Whitworth sort out that little conundrum a while ago?

loose nut
07-07-2010, 07:41 PM
Pete, if you are making very high class ground threads for NASA or CERN then then the expensive wires are a good idea but if you are make a threaded part A to fit part B for a home shop project or even most commercial work then the CCC (Cheap Chinese Crap) is plenty good enough.

loose nut
07-07-2010, 07:43 PM
once you've determined what the thread is, why do you need to "measure" it, let alone to 1 um? Didn't Mr Whitworth sort out that little conundrum a while ago?


If you are cutting a thread on a lathe, how do you know if you have it to the right dimensions if you don't measure it.

PeteF
07-07-2010, 07:49 PM
If you are cutting a thread on a lathe, how do you know if you have it to the right dimensions if you don't measure it.

It fits into the part it's designed to go into?

John Stevenson
07-07-2010, 07:53 PM
If you are cutting a thread on a lathe, how do you know if you have it to the right dimensions if you don't measure it.

What about using the tables to start off on the OD, infeed the correct depth with a correctly ground or correct insert and you will be within stated tolerances.

I have a couple of sets of wires, one Starrett set I have had for years and one Chinese set that came as a sample. Can't tell any differences.

I hardly use them as I cut to depth and then try whatever fits on the thread.
I don't care if the wires say it's correct but the nut / part won't go on. That's the part that has to fit, not the wires.

.

Deja Vu
07-07-2010, 09:37 PM
So, Nick. How does it feel to have your "tool gloat" pissed on?:D

PeteF
07-07-2010, 09:45 PM
So, Nick. How does it feel to have your "tool gloat" pissed on?:D

Sorry, didn't mean to rain on Nick's parade, though as I recall he was the one who bought up urinating first ;) Mine were genuine questions, though as you probably gathered I'm a bit sceptical about anyone needing to measure any thread to "1 um". I'm all for buying good tools, and if he's scored some of the best for a bargain then so much the better.

BobWarfield
07-07-2010, 10:35 PM
I confess, I did run immediately to Flea Bay to see what kind of thread wires could be so incredibly expensive. I wouldn't pay the asking for them, but I'd behappy to pay what Nick paid.

Just not sure how gloatible it is, LOL!

Cheers,

BW

Mcgyver
07-07-2010, 10:47 PM
Excuse my ignorance but I have never used this method of measuring threads and only seen it in books. I'm assuming it's more accurate and can handle any thread that comes along? So if you're dealing with all manner of obscure threads this would be the method to use? Conversely if "standard" threads a 5 buck thread gauge is going to tell you all you need to know?


more accurate than......? how to measure a 2" od x 20 tpi with a 5 buck gauge? you can use go/no go but thats a lot of expensive gauges to acquire (metric, imperial, whitorth even) ....and thread wires will let you tolerance things for different fits. yes, even in the home shop thats important; some you need a great fit on, others blast off another 10thou and be done. you suggested trial fitting which is ok but how do you know how much more to take off when trying for a very accurate fit? Also, frequently you can't fit parts, to large or awkward or not made yet.


It fits into the part it's designed to go into?

If all you're doing is making unc fastener type stuff, you may not need them. However there's many times when special sizes are or well fitting threads are required....ever blodge one by guessing how much more has to come off? Not with thread wires. Not to create an erroneous impression, a great deal of threads we cut are unimportant pedestrian affairs and my thread wires patiently sit in a drawer; I'm just trying to get you a sense of when and why they're needed.


Also, Nick why are these "wires" any better than the Chinese "chopsticks"? I'm presuming they're just accurately ground rods, in which case they're either on size or not.

There is no on size or not, for anything. Everything made is to tolerances and will have variance....and making thread wires is far from trivial nor is it in the same league as ground shafting. The reason is that they have to be very accurate else they drop too far or not far enough into the V profile. They are made to standards closer to gauge blocks than ground shafting....such as diam consistency between the three wires of 5 millionths of and inch and dimensional accuracy of 20 millionths. Also, they're small and hardened and can't be tapered

I have a few sets, one being made in the US that iirc set me back about $50 new... not worth getting a bamboo sliver for $50 imo....and they are something is supposed to be made to a much smaller tolerance than most of our tools

how to hold them? best is kids plasticine imo

Mcgyver
07-07-2010, 10:57 PM
What I meant by that Nick is that it seems like any wires would be easy to measure, and they will either be on size or they won't be. If they're on size, then, as somebody who has never used the system and is simply an observer, I was having trouble seeing why a $2000 set was better than a $20 set. Besides which, so you've measured your thread to 1 um. Now what?

who said they measure threads to 1 um?

think about happens when you lay the wire in the V - a small differece in the thread dia makes a bid difference how far it fits into the V.

PeteF
07-07-2010, 11:54 PM
I will presume you knew precisely what I meant by the colloquial term "on size" but for your benefit I will re-phrase it. It would be very easy to measure the wires and determine whether they meet your personal "tolerances" and/or those claimed by the manufacturer. Who said they were easy to make? All I said was that they would be easy to measure and therefore confirm (or otherwise) their accuracy. Just because something is cheap doesn't automatically mean it is inaccurate

Mcgyver
07-08-2010, 12:13 AM
I will presume you knew precisely what I meant by the colloquial term "on size" but for your benefit I will re-phrase it.

How would i know what you meant other than what you wrote and the clear context that you don't know what thread wires are for or what there tolerances are. You were talking about measuring the wires yourself and comparing them to ground bar....and then said they are on size or not....then you proceeded out of ignorance to criticize the notion that you need the wires this level of accuracy - your crack to Nick about measure threads to a millionth. The only intelligible way to help was to start with tolerance, that something isn't either on or off, and proceed to explain what and why the tolerances for thread wires are what they are.


It would be very easy to measure the wires and determine whether they meet your personal "tolerances" and/or those claimed by the manufacturer. Who said they were easy to make? All I said was that they would be easy to measure and therefore confirm (or otherwise) their accuracy. Just because something is cheap doesn't automatically mean it is inaccurate

did you read my post? how do you plan on measuring them to the required tolerance which i explain is quite small and why....you can measure hundred thousandths of an inch?

cheap does not automatically mean low quality - i gave an example of US made ones for $50....but i also explained why there are not trivial - surely you must agree there is often correlation if not causality between price and quality? when inspection equipment is to tolerances beyond what i can measure, all you can go on is trust in the manufacturer which is also a factor in what to buy, no?

anyways, maybe i'm misreading things but seems to me you wanted info and an explanation about thread wires i tried to do so, and got what a seemed a bit of a snarky response instead of thanks ?? :)

tyrone shewlaces
07-08-2010, 12:15 AM
My Chinese chopsticks are certified too... by me ! I never met a certificate I could trust. When I measured mine to see what I'd be dealing with, I figured a size or few would probably be a thou off or maybe worse. They ended up being less than a tenth off - I don't know how much, I just know that every one of them measured spot-on and I know they aren't perfect, so within .0001" works OK for me. YMMV.

When you figure that you usually have several thousandths tolerance for PD, either will do the job.

Having said all that, the very sweet end of the tool scale is always a pleasure to use, so kudos on the score man. Very cool.

PeteF
07-08-2010, 12:20 AM
WTF? Mate you seriously need a chill pill (again!). I was asking a series of questions, notice the "?" at the end of the sentences that's a clue.

MuellerNick
07-08-2010, 04:03 AM
OK boys, so this is not a tool gloat.

The set cost what it costs if you buy it new. Ask them why it is so expensive. Maybe some of you still missed the fact that the wires are held in place by a little plate. And this plate snaps (with tiny springs in the hole) onto the micrometers anvil and spindle. No wires to stick with grease or hold with rubber band (again, try that with 0.17 mm wire). Snap them on, measure, done.
Those 1m are stupid, of course. Because you never follow the rule that the exquipment should be about 5 to 10 times more accurate than what you want to measure. Threads to 1/100 mm are insane.
Shure I can check a thread with a nut laying around. But not so easy if I don't have a matching nut nor a gage. You can have any gage made in whatever pitch and diameter and tolerance you whant. But that will set you far bejond the price of any wire set. Be it Chinese or Swiss.
The method suggested to just feed inward according to some tables or math only works if you know the tool's radius exactly. I bet you do have a Mitutoyo measuring microscope to do that. I don't have. That would qualify for a different gloat.
And often enough, you do not have a mating nut or gage and there is no way to make a try fit. Too clumsy part, part not available, can't reach that thread before other production steps are finished, etc etc.

So I was simply a moron to have bought that set for that money.
Think that things would look completely different if I offer it for sale here and ask the 20.- .

Now you have to continue with your paper clips and I'll do it with my overpriced set that cost so little. Difference is, I'll always will have a smile using the set and you always will remember what I paid when you have to use your chopsticks. :p

That's what I call a gloat! It even was a real gloat, because some of you got really pi$$ed. :D


Nick

John Stevenson
07-08-2010, 04:29 AM
Why pissed.
As I said I have a Starrett set that's only been used once or twice and the Chinese set that's never been used.
If I had seen them for 20 Euros I wouldn't have bought them anyway because I have no need for them.

With full form inserts for threading now becoming very common in home shops it's very easy to get good and accurate threads by just in-feeding the correct depth. The tolerances on a normal thread Pitch Diameter are listed in thou's, not tenths of thou's.

Last night I returned a borrowed collet to the Aerospace company up the road and asked their lathe guy if he had any thread wires, he didn't.
I then asked how he knew the threads were to spec, he said they just programmed the thread detail into the lathe and that was it.

All this gear they make is checked by Boeing and Airbus, no sub-standard work would filter thru and any that was substandard would get returned, which it doesn't.

.

MuellerNick
07-08-2010, 05:45 AM
he said they just programmed the thread detail into the lathe and that was it.

Chicken egg problem.
How does he preset the tool reliably?
I do have a CNC-lathe and fullform inserts. But the tool has to be preset at least once. And the outcome has to be checked too. I can't guess springback and again, I do not have gages to check the part. I could buy a random gage for every pitch, but that wouldn't save any money and won't answer all questions.

I'm building an optical tool presetter, but still I'd have to verify the outcome by some means.


Nick

Mcgyver
07-08-2010, 06:34 AM
WTF? Mate you seriously need a chill pill (again!). I was asking a series of questions, notice the "?" at the end of the sentences that's a clue.

apogies if i overreacted....what's the 'again' for?

Black Forest
07-08-2010, 11:26 AM
It is very simple. Chinese shop sticks are for FARMERS and Swiss made wires are for serious machinists! I thought I would save you the trouble Nick of saying that!!!!!!

gwilson
07-08-2010, 11:37 AM
I think you would have to be making GROUND threads to get the kind of accuracy that these wires may be capable of. What a long thread about wires!!!

dp
07-08-2010, 11:38 AM
Congrats on the gloatable tool set. I like the idea of self-attaching holders - they're damned expensive no matter who makes them, apparently.

This also caused me to review the three-wire method and it surely isn't for me, but I don't make parts subject to inspection. One thing that jumped out was the need for a high quality of finish on the thread, and that the measurement itself is subject to known clamping force of the micrometer. Both, it seems to me, introduce more error than Chinese grinders. Repeatability in the home shop is then suspect. Especially my home shop :D

It is also clear from the associated math that any matched wire set of well known diameter can be used to specify a particular thread pitch and diameter, and which once fabricated can be measured specifically to verify one's process. If that process is repeatable, and it certainly should be, the wires can go back in the box and await the next auction.

rowbare
07-08-2010, 02:23 PM
They are used for measuring the major diameter of threads. AKA "3 wire method".
...
Price for a single pair is 80.- €. The set is complete and has 18 pairs.
...
Nick

How do you do the 3 wire method with pairs of wires :confused:?

Nice score btw...

bob

MuellerNick
07-08-2010, 02:30 PM
Posting #5, the link should give you an idea. One holder has two wires, the other one.

Nick

leesr
07-08-2010, 02:59 PM
if you make parts for customers then it's mandatory to verify the threads.

by means of either thread wires, & optical comparator or thread gages.

thread gages are preferred because it takes into account the thread form & accuracy including the correct geometric form & lead.
in other words the parts will assemble with the mating parts.

for home machining it's not necessary, cut to fit.
customer have specifications that have to be met.

I have been using Thread wires for years, & they do wear so do require replacement. Just my 2 cents

Leesr:rolleyes: :p

Alistair Hosie
07-08-2010, 03:02 PM
Arc Eurotrade is really hard to beat here in the uk I wonder if they do a monthly flyer like J and l ? Alistair

aboard_epsilon
07-08-2010, 03:21 PM
I take it these things are for the inspection room ..to take measurements showing that everything is to spec

I take it that the part has to be removed from the lathe to be able to see what you're doing with them.

I take it that they are for a serious bulk producer of all things threaded ..and wouldn't be much use too a home shop machinist ..who ain't going to remove his "one" part to see if its going OK ..then replace it and hap hazardly re-sync the lathe.

all the best.mark

MuellerNick
07-08-2010, 04:09 PM
No, you can measure in the lathe.
Except you take your part out of the chuck to mike it. ;)


Nick

boslab
07-08-2010, 04:23 PM
I did a course at NPL Teddington, thats the Natural Phsical Lab in Eng Metrollogy years back, they told us not to buy wires but use sewing needles for small sizes, we checked the diameters with a floating head bench mic complete with the then famed fiducial indicator and they were bloody nearly identical [ the aim], usefull tip for smalls when the formula needs odd sizes to get a good effective diameter reading
mark

lazlo
07-08-2010, 04:32 PM
Also, Nick why are these "wires" any better than the Chinese "chopsticks"? I'm presuming they're just accurately ground rods, in which case they're either on size or not.
more accurate than......? how to measure a 2" od x 20 tpi with a 5 buck gauge? you can use go/no go but thats a lot of expensive gauges to acquire (metric, imperial, whitorth even) ....and thread wires will let you tolerance things for different fits. yes, even in the home shop thats important;

Heck, why bother getting a Starret Crystal Pink AA-grade surface plate when I can get a "Chinese Tombstone" for $20 from Enco? The one that TexasTurnado bought had split in half and they epoxied it back together, but that ought to be good enough :p

I should probably sell my Mitutoyo gage block set too -- surely the Shars gage blocks with the photocopied inspection sheet are just as good, for 1/10th the price?

leesr
07-08-2010, 04:43 PM
Heck, why bother getting a Starret Crystal Pink AA-grade surface plate when I can get a "Chinese Tombstone" for $20 from Enco? The one that TexasTurnado bought had split in half and they epoxied it back together, but that ought to be good enough :p

I should probably sell my Mitutoyo gage block set too -- surely the Shars gage blocks with the photocopied inspection sheet are just as good, for 1/10th the price?

ROFL
surely

what is not chinese made any more.
it's hard to fork out the dough went cash is tough to have these day's.

Leesr:p

pcarpenter
07-08-2010, 04:47 PM
Heck, why bother getting a Starret Crystal Pink AA-grade surface plate when I can get a "Chinese Tombstone" for $20 from Enco? The one that TexasTurnado bought had split in half and they epoxied it back together, but that ought to be good enough :p

I should probably sell my Mitutoyo gage block set too -- surely the Shars gage blocks with the photocopied inspection sheet are just as good, for 1/10th the price?

Allright....smartarse.....we all know that there are some things where you probably should not compromise on quality. However, we did also have a posting where someone measured their chinese thread wires and found they were all within a tenth, which is more than precise enough for the job. What I haven't heard (given that) is how the $26 used Mercedes Benz wires (actual brand escapes me) were actually better in some truly demonstrable way. What I have heard is why they need to be precise and consistent without any demonstration that the cheap ones are neither of those things.

Edit-- one other thing that drives me nuts is that many seem to still think that measuring outside threads to the tenth is quite critical. In nearly every case, cutting an external thread precisely is to gain a very precise fit with a mating *internal* thread. How does the average home shop guy measure that *internal* thread to the level of precision that allows him to worry about all this gnats-arse stuff?

Paul

MuellerNick
07-08-2010, 05:01 PM
were actually better in some truly demonstrable way.

Is it really so hard to read, understand and follow a link?
Did you miss the part that they are clip-on to the micrometer and that there is no need to tangle 3 wires with some sticky and at the same time use the mike?
I'd really like to see you doing that in the lathe with 0.2 mm wire -sorry three of them- and one always falling into the chip pan.

Ah, who cares, the most clever comments are from those who don't even know what they are bitching about.


Nick

pcarpenter
07-08-2010, 05:12 PM
I understood that feature quite well and my response was not directed toward you in any way. Handy feature that little snap-in-place dohickey...nice....still has nothing to do with the folks who went off on a tangent about how the Chinese wires could not be adequate for the job because (insert overused generality about the lack of precision of unrelated Chinese tooling).

If one has a broken Chinese surface plate or Chinese gauge blocks that are not within spec....don't use them. If, on the other hand, you have thread wires that read within spec (mine cost me $6-7 as I recall), there is no reason a guy cannot use them to measure threads with a dot of modelling clay as was done for years....even with bigger name brand wires.

I am an anal-retentive engineer type and I am still amazed at the tempest in a teapot that happens over precision that is not very applicable. Thread cutting is a really great example of the old adage: Measure with a micrometer, mark with a crayon, cut with an axe. If you can measure threads to a tenth, can you cut them to a tenth? Mine have bigger burrs on them than that in most cases. Part of being precise or accurate is understanding the limits of a process and lathe cutting to a tenth is hard...lathe cutting threads in those limits is even harder.

Paul

leesr
07-08-2010, 05:38 PM
Allright....smartarse.....we all know that there are some things where you probably should not compromise on quality. However, we did also have a posting where someone measured their chinese thread wires and found they were all within a tenth, which is more than precise enough for the job. What I haven't heard (given that) is how the $26 used Mercedes Benz wires (actual brand escapes me) were actually better in some truly demonstrable way. What I have heard is why they need to be precise and consistent without any demonstration that the cheap ones are neither of those things.

Edit-- one other thing that drives me nuts is that many seem to still think that measuring outside threads to the tenth is quite critical. In nearly every case, cutting an external thread precisely is to gain a very precise fit with a mating *internal* thread. How does the average home shop guy measure that *internal* thread to the level of precision that allows him to worry about all this gnats-arse stuff?

Paul


PC

One way is :D
it would be by making your own mfg plug gages go & no.
mfg & verify the plug gages with wires.
Gages are made to the High & low limit Pitch Diameter of the thread.
use Jo Blocks to calibrate your Mic's then use (3) MOW to verify thread size.

use the plug gages to verify the Internal Thread.

Cheers
Leesr:)

leesr
07-08-2010, 05:41 PM
I understood that feature quite well and my response was not directed toward you in any way. Handy feature that little snap-in-place dohickey...nice....still has nothing to do with the folks who went off on a tangent about how the Chinese wires could not be adequate for the job because (insert overused generality about the lack of precision of unrelated Chinese tooling).

If one has a broken Chinese surface plate or Chinese gauge blocks that are not within spec....don't use them. If, on the other hand, you have thread wires that read within spec (mine cost me $6-7 as I recall), there is no reason a guy cannot use them to measure threads with a dot of modelling clay as was done for years....even with bigger name brand wires.

I am an anal-retentive engineer type and I am still amazed at the tempest in a teapot that happens over precision that is not very applicable. Thread cutting is a really great example of the old adage: Measure with a micrometer, mark with a crayon, cut with an axe. If you can measure threads to a tenth, can you cut them to a tenth? Mine have bigger burrs on them than that in most cases. Part of being precise or accurate is understanding the limits of a process and lathe cutting to a tenth is hard...lathe cutting threads in those limits is even harder.

Paul

Paul

ahhh but there is thread grinding. which is said to be more precise.
how ever CNC Thread cutting is very accurate and can be in tenths.

Cheers
Leesr:eek:

John Stevenson
07-08-2010, 05:51 PM
I remember years ago when we had one of the first CNC lathes, techie comes out and commissions it with a big crowd of blokes round including a lot of old timers who were very wary of this newfangled technology.

Said techie runs the machine thru a series of set pieces, radius's chamfers etc.

Then did the screw cutting routine, course thread at 1,000 rpm, fine thread and then a varipitch thread changing pitch about every two threads.

Old Bert moved his fag from one side of his mouth to the other hawked, coughed and spit a nice big greenie into the techies toolbox and said.

"Now lets see you do the nut for it and thread that bugger on."

.

leesr
07-08-2010, 06:25 PM
I remember years ago when we had one of the first CNC lathes, techie comes out and commissions it with a big crowd of blokes round including a lot of old timers who were very wary of this newfangled technology.

Said techie runs the machine thru a series of set pieces, radius's chamfers etc.

Then did the screw cutting routine, course thread at 1,000 rpm, fine thread and then a varipitch thread changing pitch about every two threads.

Old Bert moved his fag from one side of his mouth to the other hawked, coughed and spit a nice big greenie into the techies toolbox and said.

"Now lets see you do the nut for it and thread that bugger on."

.
JS

ROFL:eek:

Thats what I call a hacked, coughed, & buggered job.
Ya I worked with chaps like that at General Dynamics Convair.
I just a Kid. :eek:

Cheers
Leesr

Your Old Dog
07-08-2010, 06:56 PM
I might be interested in buying them.

gwilson
07-08-2010, 06:58 PM
ANY ONE NOTICE THAT I SAID GROUND THREADS WOULD BE NECESSARY FOR .0001" ACCURACY? Someone correctly pointed out that the BURRS on his threads would be higher than that.

Mcgyver
07-08-2010, 07:18 PM
Edit-- one other thing that drives me nuts is that many seem to still think that measuring outside threads to the tenth is quite critical. In nearly every case, cutting an external thread precisely is to gain a very precise fit with a mating *internal* thread. How does the average home shop guy measure that *internal* thread to the level of precision that allows him to worry about all this gnats-arse stuff?


I think part of it is risk .....if all the wires had zero taper and mic'd (with a good one :) ) to a tenth that would do for most situations one would encounter. For me, $50 for good made in usa was a no brainer as i see getting high accuracy out of a non branded product a bit of a roll of the dice. That logic doesn't mean i need 1um accuracy or have any interest in gnats asses

btw, its not about working to tenths, its about working to thou's - your thread gauges have to be to tenths to get you reliably to thou's because of how they work via laying in the V.

I don't know why there is an differentiation between home shop or one located in an industrial unit. There are lots monarchs and hardings in home shops where people are doing much finer work than the job shop down the way....type of work would i think be the determinant not location.

To your point of cutting to fit the other, agreed that's SOP. but its not inconceivable that you'd have to make a very accurate thread to suit an existing female thread. There's also making taps where obviously its important do know what you've got. heck even for a 1/2 20 standard going in a tapped hole they're handy to insure a nice fitting thread. There's lots of times you make the male to suit the female - as you point out you can't easily measure the internal without plug gauges so you work to whatever tolerance there is for the class of thread. maybe it a swiss microscope part, maybe UNC..either way the thread wires are handy. For that matter, if an incredible fit was required, you'd use the thread wire to create gauge to measure the internal thread

A problem with these discussion is in the course of trying to answer Q's or explain things people erroneously conclude you over do things; that because someone explains thread wires, why they're made accurately etc that they deserve scorn because the are probably trying to make all their threads to tenths. Hardly. As i said thread wires sit in the drawer mostly....also that I like having a set i can rely on for whatever tolerance I'm striving for bears no relativity to whether on any given job I'm gilding the lily on tolerances. They're useful regardless of the class of work

Nick you said something about not measuring in the lathe? why? I agree turn it off :D, but you don't have to remove the work to mic it :confused:

leesr
07-08-2010, 07:21 PM
ANY ONE NOTICE THAT I SAID GROUND THREADS WOULD BE NECESSARY FOR .0001" ACCURACY? Someone correctly pointed out that the BURRS on his threads would be higher than that.

GW

Yes you did

just correlated what you said.

Cheers
Leesr:D

leesr
07-08-2010, 07:30 PM
I think part of it is risk .....if all the wires had zero taper and mic'd (with a good one :) ) to a tenth that would do for most situations one would encounter. For me, $50 for good made in usa was a no brainer as i see getting high accuracy out of a non branded product a bit of a roll of the dice. That logic doesn't mean i need 1um accuracy or have any interest in gnats asses

btw, its not about working to tenths, its about working to thou's - your thread gauges have to be to tenths to get you reliably to thou's because of how they work via laying in the V.

I don't know why there is an differentiation between home shop or one located in an industrial unit. There are lots monarchs and hardings in home shops where people are doing much finer work than the job shop down the way....type of work would i think be the determinant not location.

To your point of cutting to fit the other, agreed that's SOP. but its not inconceivable that you'd have to make a very accurate thread to suite and existing female thread. There's also making taps where obviously its important do know what you've got.

A problem with these discussion is in the course of trying to answer Q's or explain things people erroneously conclude you over do things; that because someone explains thread wires, why they're made accurately etc that they deserve scorn because the are probably trying to make all their threads to tenths. Hardly. As i said thread wires sit in the drawer mostly....also that I like having a set i can rely on for whatever tolerance I'm striving for bears no relativity to whether on any given job I'm gilding the lily on tolerances. They useful regardless of the class of work

Nick you said something about not measuring in the lathe? why? I agree turn it off :D, but you don't have to remove the work to mic it :confused:

MG

checking internals has to be done with other means, Yes do you agree.
I agree with your view point on accurate thread wires.
except my statement was about if your making parts for customers,
vs a home project.

who cares if it's a home project as long as it fits.

Cheers
Lee;)

John Stevenson
07-08-2010, 07:51 PM
MG



who cares if it's a home project as long as it fits.

Cheers
Lee;)

Who cares if it's a customers part ? most of them are wankers anyway, all mine just keep me from playing. I do my utmost to upset them but they just laugh and treat it as a joke.

Done two wanked out POS Bridgeport motors this week already and it's only the first week of the month

If you get a choice of a step speed or varispeed, buy the bloody step speed and fit a VFD, those Varsipeeds are an accident looking to happen.

Friday tomorrow, sorry it's actually Friday here already, Friday is play day, make gismo's for John day,

No chance. Big varispeed drive with sheathe knackered and shaft bolloxed, two 5Hp pumps with extended stainless steel shafts badly worn, 6 stainless turn buckles with RH and LH thread needed, armature with a worn end and a broken cast iron motor foot........

Mcgyver
07-08-2010, 08:01 PM
MG

checking internals has to be done with other means, Yes do you agree.


Agreed. However, if for some reason i was charged with making an internal thread to some super high limits of my equipment and ability to measure...out would come the thread wires..no I haven't figured out how to check internal threads with wires but i don't how i'd do this job without being able to make some very accurate (to using my best mic and cursing at the burrs, btw, there shouldn't be much of a burr on the flank where the wires engage??) plug gauges.


I agree with your view point on accurate thread wires.
except my statement was about if your making parts for customers,
vs a home project.

who cares if it's a home project as long as it fits.

i'm one finicky customer :) I'd counter that fit matters when it matters to the extent it matters. Many home shops are making things for customers but you are right that if there's no customer there's massive latitude on how well or not something is made. still, thats not causality that they home shop can't do as good or better work or strive for similair levels of accuracy or benefit from similair quality tools as its commerical brethen

hence my point, the accuracy, equipment etc are a product of what you're doing not where......building onseys twoseys for yourself lets you go off print, but you still have to have the required fit, and I generally find if I don't work very hard to stay on print projects come out working like and looking like crap :p

loose nut
07-08-2010, 08:05 PM
It fits into the part it's designed to go into?

What if that part hasn't been made yet or it is some kind of odd ball thread. You have to measure it somewhere in the production chain to see that everything is OK. You don't have to use wires, thread mics can be used or a gauge, which could be a nut or the part it threads into if you have it, wires are used by many because they are usually cheaper then other methods.

PeteF
07-08-2010, 08:26 PM
Cripes, I think I created a monster :D

It's certainly interesting reading, and thanks for those who explained the process. If I were Nick I'd be just as chuffed with my find.

While it's true I was playing "devil's advocate" one thing that has come up is a few people trashing Chinese stuff and saying "why not just buy Chinese stuff", I'd say, yes, why not indeed. Don't get me wrong, my workshop is full of German and other high quality tools (there's a plug for you Nick), because I like good quality. I'd rather have a few things of really good quality, than a lot of crap. My car is European, most of my tools European, heck even my wife is European :D Having said that, I've also got a fair share of HF and Chinese "junk", either when it just doesn't matter (does a Snap-on dead-blow hammer really work any better than my HF dead-blow?). Alternatively can I easily verify the accuracy of the alternative? Can I easily verify the accuracy of my micrometers across their complete range? No not really, hence why all mine are Mitutoyo. But could I measure a set of thread wires? heck yeah, even I can do that! It's not necessarily that the Chinese stuff is crap and the US made stuff is always good, far from it. It's just that personally I feel I can trust the specs of a western brand, but certainly would never trust a Chinese brand and would always want to check it if I could. So that was why all the questions, not to poo-poo somebody's purchase, not to ruffle any feathers, but simply to question, in much broader terms than simply these wires, why people get so wound up about brands when, it seems to me, there is no need. I laugh at women who are, in my mind at least, so gullible to pay >$1000 for a handbag just because it says Gucci or whatever on the side. But I can't help but think there's much the same going on with some here ;) It's nothing more than brand snobbery.

Stir the pot, now watch me run :D

aboard_epsilon
07-08-2010, 08:34 PM
Cripes, I think I created a monster :D

It's certainly interesting reading, and thanks for those who explained the process. If I were Nick I'd be just as chuffed with my find.

While it's true I was playing "devil's advocate" one thing that has come up is a few people trashing Chinese stuff and saying "why not just buy Chinese stuff", I'd say, yes, why not indeed. Don't get me wrong, my workshop is full of German and other high quality tools (there's a plug for you Nick), because I like good quality. I'd rather have a few things of really good quality, than a lot of crap. My car is European, most of my tools European, heck even my wife is European :D Having said that, I've also got a fair share of HF and Chinese "junk", either when it just doesn't matter (does a Snap-on dead-blow hammer really work any better than my HF dead-blow?). Alternatively can I easily verify the accuracy of the alternative? Can I easily verify the accuracy of my micrometers across their complete range? No not really, hence why all mine are Mitutoyo. But could I measure a set of thread wires? heck yeah, even I can do that! So that was why all the questions, not to poo-poo somebody's purchase, not to ruffle any feathers, but simply to question, in much broader terms than simply these wires, why people get so wound up about brands when, it seems to me, there is no need. I laugh at women who are, in my mind at least, so gullible to pay >$1000 for a handbag just because it says Gucci or whatever on the side. But I can't help but think there's much the same going on with some here ;)

Stir the pot, now watch me run :D

hmmm
dead blow hammers ...

heard a few stories in these forums ..or PM, on how these hammers ..(who ever made them) suddenly after so many years and months crack up and fall apart ..even when stored in a drawer...seems the material they are made out of just deteriorates overnight..after a set period...ticking time bombs....very weird

all the best.markj

PeteF
07-08-2010, 08:42 PM
hmmm
dead blow hammers ...

heard a few stories in these forums ..or PM, on how these hammers ..(who ever made them) suddenly after so many years and months crack up and fall apart ..even when stored in a drawer...seems the material they are made out of just deteriorates overnight..after a set period...ticking time bombs....very weird

I'll keep that in mind :D I'd reckon it was PM you saw that for sure. Still, could be worth the chance hanging on to mine for a few more years, just for an experiment ;)

lazlo
07-08-2010, 09:10 PM
, we did also have a posting where someone measured their chinese thread wires and found they were all within a tenth, which is more than precise enough for the job.

We did? I'd be surprised if the Chinese can make anything for $6 that's accurate to a tenth.

Have you miked your Chinese thread wires for size and roundness?

Mcgyver
07-08-2010, 09:12 PM
,(does a Snap-on dead-blow hammer really work any better than my HF dead-blow?). Alternatively can I easily verify the accuracy of the alternative? Can I easily verify the accuracy of my micrometers across their complete range? No not really, hence why all mine are Mitutoyo. But could I measure a set of thread wires? heck yeah, even I can do that!

gucci and snapon are full on drinking the koolaid imo, one has to apply intelligence in the buying decision - its a quest for value in an imperfect world...sometimes its worth it to be pay a small premium for a brand you trust because what you're spending the money on really is risk management. like insurance. Gucci for exampe is just spending it on BS tripping, at least imo.

On the thread wires you've missed that point. You buy a cheap set for whatever instead good ones for 50, great. You want to sit down and measure every one and every point over their lengths - even if you could do it? (describe how to measure for roundness) And if you find an error you want to take the time and hassle to return it and get another set and do it over again, to save what? and then you;ve had it a few years and notice they really weren't hardened properly and are all scratched to crap resulting in no accuracy. I have time for all that if its 20 vs 2000, not for 20 vs 50 but suit yourself

A day ago you didn't know what thread wire were now you're proferring how one should buy them? :D

PeteF
07-08-2010, 09:28 PM
gucci and snapon are full on drinking the koolaid imo, one has to apply intelligence in the buying decision - its a quest for value in an imperfect world...sometimes its worth it to be pay a small premium for a brand you trust because what you're spending the money on really is risk management. like insurance. Gucci for exampe is just spending it on BS tripping, at least imo.

On the thread wires you've missed that point. You buy a cheap set for whatever instead good ones for 50, great. You want to sit down and measure every one and every point over their lengths - even if you could do it? (describe how to measure for roundness) And if you find an error you want to take the time and hassle to return it and get another set and do it over again, to save what? and then you;ve had it a few years and notice they really weren't hardened properly and are all scratched to crap resulting in no accuracy. I have time for all that if its 20 vs 2000, not for 20 vs 50 but suit yourself

A day ago you didn't know what thread wire were now you're proferring how one should buy them? :D

No I'd suggest you've missed the point. Firstly, just for the record, I never said I didn't know what thread wires were, please read my first post again, I said I have never USED this method and only read about it.

My point is nothing about thread wires, it is about people blindly buying high priced brand names and assuming that they are always going to be better than a no-brand. Even worse, assuming that something from the US is necessarily good, something from China is crap. Well I'm here to tell you I've bought some truly abysmal products that proudly displayed "Made in USA" I can tell you! In case you think I'm being anti-American, please feel free to substitute "Made in Australia" as that is just as relevant.

Incidentally can I ask why you always feel it's necessary to "play the man"? Since going from a mostly passive reader to an active poster you've taken a few swipes at me, maybe that's your sense of humour (or humor as the case may be) but of course the nature of the communication is something said in jest is not always read that way at the other end ... smily face or not!

BobWarfield
07-08-2010, 09:30 PM
If you want that page in English, it's here:

http://www.emte.ch/S-Produkte%2003.asp

At some point I got the price list and a very nice Excel worksheet for using thread wires in English, but can't figure out how I got it to give a link.

DOH!

BW

lazlo
07-08-2010, 09:33 PM
My point is nothing about thread wires, it is about people blindly buying high priced brand names and assuming that they are always going to be better than a no-brand. Even worse, assuming that something from the US is necessarily good, something from China is crap. Well I'm here to tell you I've bought some truly abysmal products that proudly displayed "Made in USA" I can tell you! In case you think I'm being anti-American, please feel free to substitute "Made in Australia" as that is just as relevant.

Are you Tiffie posting on a different account? Are you going to start adding unrelated Wikipedia links? :)

The irony is you're accusing McGyver of being an American bigot, when he is, in fact, Canadian. :rolleyes:

If you're happy with the stuff you've bought from China, that's great. But some of us would prefer to buy German, English, American, Swiss, Japanese, or even Australian tools, because they're almost always vastly better quality.

PeteF
07-08-2010, 09:51 PM
The irony is you're accusing McGyver of being an American bigot, when he is, in fact, Canadian. :rolleyes:

If you're happy with the stuff you've bought from China, that's great. But some of us would prefer to buy German, English, American, Swiss, Japanese, or even Australian tools, because they're almost always vastly better quality.

What??? You're joking right? How in the hell have I accused him of being an American bigot? I have no idea where the heck he lives, I don't particularly care for that matter, it's completely irrelevant, so why do you even mention it? There have been plenty of people, both on this thread and elsewhere on the board that have either implied, or said outright, that Chinese products are always inferior to western made products. I used the US as an example but didn't want anyone to think I was having a go at the US, not being a US citizen myself.

Your second paragraph. Thanks, I couldn't have put it better myself ;)

Mcgyver
07-08-2010, 10:19 PM
yeah, where is OT, a couple of wiki links 'll settle things



Incidentally can I ask why you always feel it's necessary to "play the man"?

You can ask anything you like, I don't really know what that means though, I think over time i ask as many questions as i answer but whatever.

Pete, ok you asked. You made a number of posts in various threads with disparaging innuendo, not directed at anyone in particular, but irritating and obvious to which body of opinion they were addressed none the less. I'm forming an opinion. Then i see your behaviour here, as a beginner telling someone like Nick who knows a bit
Besides which, so you've measured your thread to 1 um. Now what?, not exactly Dale Carnegie now is it? nothing that bad but just a accumulation of snotty remarks. So I'm predisposed to thinking what type you are, but ok I do a bunch of typing and trying answer the question...which is responded with a tone and no thanks. so i was ready to be pissed.

Each of us owns the reaction we generate in others. I guess I was expecting or not really carrying about the reaction I got from you, immature granted and not what i aspire to....but did you stop to wonder why you got the reaction you did?

End of the day, as you point out much gets missed in typed sterile communication and my reaction is not my preference regardless of the circumstances so I will apologize for allowing these things to annoy me and flush the whole affair as bad communication. you'd still be welcome to visit the shop and have a beer if in TO

PeteF
07-08-2010, 11:53 PM
I'm forming an opinion. Then i see your behaviour here, as a beginner telling someone like Nick who knows a bit

Ok well here's the deal where I'm siting, just to clear the air. At the moment I'm sitting here at my desk, not by choice, but because somebody cleaned me up in a car while I was out riding my bike. Result, one broken collarbone. One arm in a sling, no work, and only now can I undertake light duties. As a result I'm willing to enter discussions, and even create discussions, that I wouldn't normally have the time to do, or arguably the inclination. If anyone wants to join in, that's fine, if they don't that's fine too.

"Playing the man" I thought was a pretty universal term, but clearly I'm mistaken. It means somebody who goes into a sporting event and doesn't worry about what the ball or puck is doing, they're more intent on taking down the opponent. "Goons" that are sent into a hockey game would be one example you may be familiar with, they have no interest in the puck, indeed they're often not even especially good hockey players, their whole intent is simply to take down a particular player. I went to some great lower grade hockey games in Canada, better than the NHL games I thought. I mentioned that to a local and he explained to me that the young guys are hoping to be selected for bigger and better things, and if they can't be selected for playing well, they'd hope to be selected for playing rough! Maybe a story, I don't know.

In a "discussion" it seems some try the same tactic, failing to address in any way the points that are being made, much easier to try to discredit the "opponent". I've made it perfectly clear that I was, and am, playing the devil's advocate in this discussion. I made it perfectly clear that if you came in to my very modest (yes beginner's if it makes you feel still better) workshop you would in fact find it comprised some pretty good kit, not too much of it, but good just the same. But, apparently unlike some, I'm not so far up my own arse that I can't admit to buying Chinese stuff too.

Nick came up and said he's bought these wires, I thought good job, but then John said he's been taken for a ride, Chinese versions are available much cheaper. It seemed to me to degenerate into a typical pissing contest. If you went back and read the thread again, more carefully than you clearly have at the moment, you'd note that I have never "told' Nick anything. On what basis would I do that? For your information I've studied all Nick's videos on scraping and read what he writes very carefully, as he has some great knowledge he's very willing to share. It seems even Nick, speaking in a second language got it, "Ah, who cares, the most clever comments are from those who don't even know what they are bitching about." What I did do however is question the need for such accuracy and that questioning was echoed by others I don't believe fall into your "beginner" category More the point I questioned the wholesale philosophy that "Made in xxx" = good "Made in yyyy" = bad. Others here have taken the time to measure their "chopsticks" and found them to be suitably accurate. But when I question whether there's always a need to buy "top shelf" it's "play the man" time.

The bottom line is I honestly couldn't give a flying toss what you think of me. I don't know you, it sounds like I don't particularly want to know you, and I'll most likely never know you. Maybe I'm mistaken, time will tell. However, if you expect me to bow down in eternal gratitude for taking so much of your time to explain things to me, then I'd suggest you're mistaken. If you don't like what I have to say there's an easy solution, don't read it, never mind respond to it! But if you chose to, please do us all a favour and read it properly and in the context of where it's written. Meanwhile, if you don't like my playful digs at people's immaturity (and sadly that thread has been deleted) then tough mate! As an outsider watching the train-wreck that was the thread about another BB I simply couldn't believe some people were actually grown men. Immaturity; you're telling the story!

It's quite interesting how defensive people get when somebody dares to question purchasing behaviour, as if it were a personal affront to their own egos. It probably says more about their personality than any slander I'd hope to come up with, even if that WAS my intent!

J Tiers
07-09-2010, 12:12 AM
What on EARTH is teh fuss about?

I took it that these items that Nick found are

1) similar in accuracy to "Deltronic pins"

2) set up with a very handy arrangement for actual use.


if so, they qualify as a good deal at the price, since the price wouldn't likely buy 10mm length of one pin, let alone the set.

"probably not needed in the home shop"?

Depends on what you do...... I have a bunch of gages, gage pins, gage blocks, thread gages male and female, go and no-go.

Is it overkill for the home shop? Sure.... But I make prototypes for work, and it is good to be able to measure to the same standards that the other shops might (if they had the equipment, some I know do not)

So maybe those who say "home shop" and think of someone making models and fitting this part to that, might need to recall that a number here do work for others, for racing, and / or otherwise must fit their parts to the parts of other makers.

PeteF
07-09-2010, 12:17 AM
Indeed Jerry, in fact some people enjoy working to a higher level of accuracy than may be "required" simply because they can. That's the beauty of a "home shop", there's only one person who decides what you make, how you'll make it, and just how accurately it will be made!

dp
07-09-2010, 12:49 AM
What??? You're joking right? How in the hell have I accused him of being an American bigot?

Over time you have to accept that Lazlo is dislexic or has problems of confusion and absorption with long chains of thought. Bless his heart, he does that to me all the time and I've finally decided to humor him because I like him. Must be the Texan in me.

MuellerNick
07-09-2010, 02:52 AM
Nick you said something about not measuring in the lathe? why? I agree turn it off ,

That was not me.
Maybe it was IKnowBetterButWhatAreYouTalkingAbout


Nick

MuellerNick
07-09-2010, 03:32 AM
Regarding the useless accuracy of the wires, a bit of math helps:
The wires are to +/- 1m.
So with 1m difference, the wire slips 2m deeper into the Vee. But only on one side, you have an other Vee on the other side. This adds up to 4m, so +/- 4m certainty for +/- 1m difference of the wire. Then you have to add the micrometer's accuracy to know how accurate you actually are measuring.

Now you come with your cheap chopstick wire that you calibrated by yourself. How accurate is your bargain mike from the "happy green elephant tractor factory"? +/- 2m? The outcome is 4-fold + the micrometer's accuracy on top of it.

Metrology is a bit more than "It is what I read".

Shure I can't measure an ID thread with the wires, but I always can make a plug, a conical plug and measure this one quite exactly. The distance how far I can screw the plug in gives a reading of the internal thraed's size.

I have been asked to make 10 backplates for Boley lathes. They do have an odd thread, IIRC M61 * 3 with 55. I'd have a hard time with try-fitting that. The only way is by making a gage that I know the size of. Just this single job will pay back the thread wires manyfold.


Nick

michaelantipode
07-09-2010, 04:17 AM
Nick,
You were lucky on that buy. I am envious.

Of course precision is important in a nation which builds the machines other countries use to build machines. If I could afford it, I would always buy Swiss or German tools.

oldtiffie
07-09-2010, 06:41 AM
I'm forming an opinion. Then i see your behaviour here, as a beginner telling someone like Nick who knows a bit

Ok well here's the deal where I'm siting, just to clear the air. At the moment I'm sitting here at my desk, not by choice, but because somebody cleaned me up in a car while I was out riding my bike. Result, one broken collarbone. One arm in a sling, no work, and only now can I undertake light duties. As a result I'm willing to enter discussions, and even create discussions, that I wouldn't normally have the time to do, or arguably the inclination. If anyone wants to join in, that's fine, if they don't that's fine too.

"Playing the man" I thought was a pretty universal term, but clearly I'm mistaken. It means somebody who goes into a sporting event and doesn't worry about what the ball or puck is doing, they're more intent on taking down the opponent. "Goons" that are sent into a hockey game would be one example you may be familiar with, they have no interest in the puck, indeed they're often not even especially good hockey players, their whole intent is simply to take down a particular player. I went to some great lower grade hockey games in Canada, better than the NHL games I thought. I mentioned that to a local and he explained to me that the young guys are hoping to be selected for bigger and better things, and if they can't be selected for playing well, they'd hope to be selected for playing rough! Maybe a story, I don't know.

In a "discussion" it seems some try the same tactic, failing to address in any way the points that are being made, much easier to try to discredit the "opponent". I've made it perfectly clear that I was, and am, playing the devil's advocate in this discussion. I made it perfectly clear that if you came in to my very modest (yes beginner's if it makes you feel still better) workshop you would in fact find it comprised some pretty good kit, not too much of it, but good just the same. But, apparently unlike some, I'm not so far up my own arse that I can't admit to buying Chinese stuff too.

Nick came up and said he's bought these wires, I thought good job, but then John said he's been taken for a ride, Chinese versions are available much cheaper. It seemed to me to degenerate into a typical pissing contest. If you went back and read the thread again, more carefully than you clearly have at the moment, you'd note that I have never "told' Nick anything. On what basis would I do that? For your information I've studied all Nick's videos on scraping and read what he writes very carefully, as he has some great knowledge he's very willing to share. It seems even Nick, speaking in a second language got it, "Ah, who cares, the most clever comments are from those who don't even know what they are bitching about." What I did do however is question the need for such accuracy and that questioning was echoed by others I don't believe fall into your "beginner" category More the point I questioned the wholesale philosophy that "Made in xxx" = good "Made in yyyy" = bad. Others here have taken the time to measure their "chopsticks" and found them to be suitably accurate. But when I question whether there's always a need to buy "top shelf" it's "play the man" time.

The bottom line is I honestly couldn't give a flying toss what you think of me. I don't know you, it sounds like I don't particularly want to know you, and I'll most likely never know you. Maybe I'm mistaken, time will tell. However, if you expect me to bow down in eternal gratitude for taking so much of your time to explain things to me, then I'd suggest you're mistaken. If you don't like what I have to say there's an easy solution, don't read it, never mind respond to it! But if you chose to, please do us all a favour and read it properly and in the context of where it's written. Meanwhile, if you don't like my playful digs at people's immaturity (and sadly that thread has been deleted) then tough mate! As an outsider watching the train-wreck that was the thread about another BB I simply couldn't believe some people were actually grown men. Immaturity; you're telling the story!

It's quite interesting how defensive people get when somebody dares to question purchasing behaviour, as if it were a personal affront to their own egos. It probably says more about their personality than any slander I'd hope to come up with, even if that WAS my intent!

I was going to keep out of this, but as I got a "mention"



Originally Posted by PeteF
My point is nothing about thread wires, it is about people blindly buying high priced brand names and assuming that they are always going to be better than a no-brand. Even worse, assuming that something from the US is necessarily good, something from China is crap. Well I'm here to tell you I've bought some truly abysmal products that proudly displayed "Made in USA" I can tell you! In case you think I'm being anti-American, please feel free to substitute "Made in Australia" as that is just as relevant.


Are you Tiffie posting on a different account? Are you going to start adding unrelated Wikipedia links? :)
The irony is you're accusing McGyver of being an American bigot, when he is, in fact, Canadian. :rolleyes:

If you're happy with the stuff you've bought from China, that's great. But some of us would prefer to buy German, English, American, Swiss, Japanese, or even Australian tools, because they're almost always vastly better quality.

I thought I'd "chip in".

This is turning into another "pile on" where a lot see the "big guys" and the "Senior" and "1,000's of posts" members "getting into it (Peter)" and as no one other than Peter is "kicking back" it seems that some think that they too can "pile on" and "get in for their licks and kicks" with little chance of "getting hurt" and to "mirror" and "keep on-side" with those "big guys" and scoring some (more??) "brownie points" (Its called "brown-nosing" here in OZ).

Peter.

You are doing OK, keep your cool and your feet on the ground and sticking to the subject.

You are quite within your rights to ask ask a question, make any remark, and expect a civil and direct question to a civil and direct question.

The short answer of course is in Machinery's Handbook and similar references. I will address that later.

Here are my "Chinese" "3-wires", bought in/from the USA and very accurate:
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/3-wire2.jpg

Here are the tables that many are referring to that relate to this set of wires:
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/3-wire3.jpg

First of all, you are NOT limited or restricted to those wires - its just that the table is made to suit those wires.

"W" - the wire diameter is a variable and can be any diameter that touches both 30 degrees off-set sides/flanks of the thread - but the nearer the pitch diameter "E" the better.

The equations allow for any size wires.

All wires in a set of three should be very accurate - say +/- 0.0001" or better - between highest and lowest - but for shop work +/- 0.0005" would be OK.

Any precision wire - say "drill rod" or "O1" (USA) or "silver steel (OZ, NZ and UK) will suffice.

The tables above advise that there are limits (ie highest and lowest) between which the Pitch Diameter should be - and it refers to "Tables" and "Machinery's Handbook". Those limits are surprisingly wide. There is MUCH more than just "accurate wires" and a "micrometer" to consider.

I strongly advise the commentariat to have a really good read of Machinery's Handbook and understand it and use it as a base reference - and a "touch-stone" - before saying too much about "what is" when is it may not be so at all. See MHB 27 pages 1894 - 1911.

In theory the common general equation used is only correct when the thread "V" has zero helix angle - ie it is a groove and not screw thread, but the accuracy is generally OK provided the helix angle does not exceed 5 degrees.

There is second more accurate equation that addresses all helix angles - but it is not in common use.

Next, the "3-wires" method relies on the 60 degree (UNC/UNF/ISO etc) or 55 degree (BSW/BSF etc.) thread angle being absolutely accurate and symmetrical about an axis normal to the pitch cylinder axis as well as of very good finish and with very straight sides. It takes no account of thread major or minor diameters nor of any flats or radii at the crest or root of threads. If there are any of these errors the thread will or may be unsatisfactory even if the "measurement over the wires" is satisfactory.

The equation is very easy to use and is at or only slightly above "Shop Maths 101". Any High School or College student at say year 8 (most) would have no problem inserting the values required into the equation/s and extracting the correct value/s from it/them.

Further, if the wires are tapered - say 0.001" (or more) over the 3" length of the wire and the taper was reasonably constant, I could pick a point on the taper, mark it, measure it, and use it at that measured point and I would get the same answer as if the wire was truly and accurately parallel and the same diameter from end to end.

Actually only one wire is required although the equation has to be solved for three wires.

I could use the shank of a new drill bit and get a very good result.

Provided that I solve for the measurements over the wires (3 or 1) at the upper and lower limits of the thread pitch diameter - that will give me the limits of the measurement over the wire/s that I need to stay within the requirements of the external screw thread for the particular thread size and class.

garagemark
07-09-2010, 08:13 AM
Tiffie, very good information about a subject I know very little about. Thank you.

For (some of) the rest of you..... This place is beginning to look like a troll training center for the rest of the Internet. It is not manditory to get into a contest about all subjects here. Simple disagreements are fine, and even a bit of Chi vs. (insert your preference) can be constructive, but the personal attacks and name calling are just useless. Are y'all not gettin any? If yer backed up, a good woman (or whatever your preference) might settle some of you down a little bit.;)

I think Nick got a VERY nice score. Being a tool junkie myself, I would have snapped them up in a flash. I would have probably never used them since I do not make shuttle parts, but I would still have had a tool set that I could never afford in real life (this is about a very expensive item, not a Chicom set). And my daughter would have had yet one more unkown item for the auction upon my demise (that's the true goal- to drive her insane while she's liquidating my shop).:D

Cheers
Mark

MuellerNick
07-09-2010, 08:15 AM
That table seems to be quite off!
The optimum wire diameter is calculated by:

diam = P / (2 * cos(alpha/2))

With 0.5 mm pitch (metric; 60), the wire should be 0.288 mm. The standard (DIN 2269) says, that the thread should be checked close to the pitch diameter (I think you call it that way). Your table says 0.4572 mm (whatever that nonsense is to 0.1m accurate)


Nick

J Tiers
07-09-2010, 08:22 AM
A few random points.....


1) ANY reasonably accurate set of thread wires (with a good tenths mic) is going to be at least an order of magnitude more accurate than the common home shop technique of "ah'm dun whin th nut fit's 'er"........

2) The chinese own equipment that will make plenty accurate thread wires..... the only question, which applies to any "precision" tool, is "did they do it right on THIS one?".

That question/issue has been a problem on many things from china, but that isn't proof of badness in any particular case....... even the chinese might randomly make some very accurate wires.


3) "Play the man" has an alternate meaning, which amounts to "man up and take it"......

MuellerNick
07-09-2010, 08:41 AM
2) The chinese own equipment that will make plenty accurate thread wires..... the only question, which applies to any "precision" tool, is "did they do it right on THIS one?".


This is an endless discussion. Just some random points:
* I do have a Chinese lathe, it is crap
* I have seen and scraped in other Chinese lathes/mills to know what I'm talking about.
* I had one inside micrometer, that cost me more time and money by the wrong pitch (4m / mm IIRC) than a decent one would have cost me. I finally "fixed" it with a sledge hammer.
* Currently I got a cross slide (Chinese, you guessed right) to scrape in. It is so much off that you won't believe it (I'll post a video).
* Bought a Chinese clone of the Lamello (woodworking for dovels), the time wasted trying to fix it and the crap it produced ...
* Had a 90 toolmakers angle that fell apart after 1 year. It was super-glued.

I'm fed up with their crap. They can sell it to the bargain-hunters so they later can wine about losing jobs. I think it's more clever to support local (or at least western + Japan) economy.


Nick

Glenn Wegman
07-09-2010, 09:02 AM
That table seems to be quite off

That is due to the fact that the wires in Tiffies post are Imperial sized wires that have the numbers "adjusted" to measure Metric pitches. (Here we go again Pete:) )

That is another difference between "real" thread wires such as Van Keuren, Deltronic, etc., and the inexpensive sets such as PeeDee. The "real" sets use the "best" wire size (calculated to contacted the flanks at the pitch diameter) and there is a set of wires for each particular thread pitch, as well as a set for Imperial, a set for metric, a set for 55 flanks, etc., whereas the cheaper sets use less wire sizes and calculate the measurement over wires according to the "closest" wire size in the set.

Another difference, leading to the difference in cost, is that "real" wires are lapped to, at least five decimal places in accuracy and the three wires are exactly matched in size. (Imperial decimal places that is)

Keep in mind that wires are used by gauge makers to make go-no go gauges that need to be quite accurate, but that kind of accuracy does not necessarlly apply to home use.

Nice wires Nick!

PeteF
07-09-2010, 09:03 AM
Tiffie, thanks for taking the trouble; on all counts.

Personally I view a piece of Chinese equipment as a kit. The big issue with a lot of Asian made gear isn't the facilities, as a lot of people think, it's the quality control. So it can be a complete lucky dip as to what you're getting; it MAY be quite good quality, but it MAY not be either. I view it as a bunch of parts and if it happens to work straight "out of the box" that's a bonus.

I think what some may overlook however is that the Chinese goods allow access to products that may not otherwise be affordable. A really good example of this for us in Australia are surface plates, good used name brand surface plates simply do not come up in Australia, end of story. The only option is to buy new. I'm sorry but I don't have $1500+ to import a Starrett surface plate, it's either Chinese or it's nothing. So I have a Chinese plate, it has a map, but do I trust it? In all honesty no. It's probably ok, and the map looks legit. But I'd certainly feel more comfortable if I could check it. See QC above. BUT I have a plate, and it sure is better than trying to spot off a concrete floor!

Pete

Edit: Glenn, nooooooo!!! Don't mention the "M" word :)

lazlo
07-09-2010, 09:05 AM
Even worse, assuming that something from the US is necessarily good, something from China is crap. Well I'm here to tell you I've bought some truly abysmal products that proudly displayed "Made in USA" I can tell you!


The irony is you're accusing McGyver of being an American bigot, when he is, in fact, Canadian.

What??? You're joking right? How in the hell have I accused him of being an American bigot?

The way I read that statement (which is quoted ad nauseum by Tiffie) is:

"You're an American blindly buying Made in USA tools and criticizing Chinese tools when Americans make truly abysmal products too."

The reality is, Nick, and McGyver, and myself, and many others here buy quality tools, regardless of country of origin. So turning it into an Anti-American rant when the OP is German, and the guy you're attacking is Canadian, makes no sense at all.

Nick got a great deal on a set of precision thread wires. Like I said before, if your Chinese thread wires are good enough for you, then great -- but don't crap on Nick's post because you think they're too accurate for him :(

lazlo
07-09-2010, 09:16 AM
The chinese own equipment that will make plenty accurate thread wires..... the only question, which applies to any "precision" tool, is "did they do it right on THIS one?".

For $6, I'd be willing to be the Chinese thread wires are piano wire. There's no way they're selling 48 precision ground wires for $6, and hell -- that's the price Arc Euro is selling them, at a profit, which means the Chinese probably sold them to Arc Euro for $2 plus shipping.

PeteF
07-09-2010, 09:20 AM
The way I read that statement (which is quoted ad nauseum by Tiffie) is:

"You're an American blindly buying Made in USA tools and criticizing Chinese tools when Americans make truly abysmal products too."

The reality is, Nick, and McGyver, and myself, and many others here buy quality tools, regardless of country of origin. So turning it into an Anti-American rant when the OP is German, and the guy you're attacking is Canadian, makes no sense at all.

Nick got a great deal on a set of precision thread wires. Like I said before, if your Chinese thread wires are good enough for you, then great -- but don't crap on Nick's post because you think they're too accurate for him :(

An anti-American rant now hey? Holy cow mate :rolleyes: Look I really hate to disappoint you, but I'm not "attacking" anyone. It's clear you're trolling for an argument and while I'm all for a discussion, even a heated discussion is fine, but otherwise you may be better off in the "I hate the world BB" because I have no interest in going any further with your troll. You're quoting things that I have never said, never meant, and if you read them that way, I see that as your problem and I'm sure as heck not going to make it mine.

Mcgyver
07-09-2010, 09:20 AM
For $6, I'd be willing to be the Chinese thread wires are piano wire.

drops from the spring plant :)

vpt
07-09-2010, 09:25 AM
"ah'm dun whin th nut fit's 'er"........




Thats what I do.

lazlo
07-09-2010, 09:28 AM
It's clear you're trolling for an argument

You're quoting things that I have never said...

You didn't say this?


Even worse, assuming that something from the US is necessarily good, something from China is crap. Well I'm here to tell you I've bought some truly abysmal products that proudly displayed "Made in USA" I can tell you!


you may be better off in the "I hate the world BB"

LOL! You're the one that's thread crapping! Personally, I think Nick got a great deal!

PeteF
07-09-2010, 09:33 AM
Read the post. Again. Slowly this time. Notice the word "some"?

Yes I also think Nick got a great deal, which is why I said so. Numerous times in fact.

oldtiffie
07-09-2010, 09:36 AM
Originally Posted by lazlo
The way I read that statement (which is quoted ad nauseum by Tiffie) is:

"You're an American blindly buying Made in USA tools and criticizing Chinese tools when Americans make truly abysmal products too."
The reality is, Nick, and McGyver, and myself, and many others here buy quality tools, regardless of country of origin. So turning it into an Anti-American rant when the OP is German, and the guy you're attacking is Canadian, makes no sense at all.

Nick got a great deal on a set of precision thread wires. Like I said before, if your Chinese thread wires are good enough for you, then great -- but don't crap on Nick's post because you think they're too accurate for him


An anti-American rant now hey? Holy cow mate :rolleyes: Look I really hate to disappoint you, but I'm not "attacking" anyone. It's clear you're trolling for an argument and while I'm all for a discussion, even a heated discussion is fine, but otherwise you may be better off in the "I hate the world BB" because I have no interest in going any further with your troll. You're quoting things that I have never said, never meant, and if you read them that way, I see that as your problem and I'm sure as heck not going to make it mine.

Lazlo.

Just when and where did I make that statement that you quoted:


The way I read that statement (which is quoted ad nauseum by Tiffie) is:

"You're an American blindly buying Made in USA tools and criticizing Chinese tools when Americans make truly abysmal products too."
You are being devious and disingenuous again. I've pulled you up about that sort of thing on several occasions.

If you had said that I inferred or seemed to infer, then that may or may not be a fair interpretation or inference that you drew.

But if you must or feel compelled to quote me - do it precisely and accurately - with source/s - or not at all.

If I have not made it clear to you as to what I think, then all you need is a direct question to which I will give (you) a direct reply.

Carld
07-09-2010, 09:48 AM
Hmmm, having just read the entire 9 pages of posts I think Nick got a nice deal on his thread wires. The holders seem to be a good idea to me. The size and tolerance of the wires are important and it's easy to determine the diameter of wire needed and then measure the ones you have to see if they are within tolerance.

There is one thing that only a few have pointed out and it has been passed over several times. Have you ever looked at a cut thread under a microscope? The surface looks terrible and like the metal has been ripped out. The wires are round and the contact area of the wire on the thread V is small and varies from pass to pass of the cutter. That puts errors of measurement in the process so even the most accurate wires may render an error in the PD reading.

For the outcome to be as accurate as some are expressing you would have to have a ground thread because the surface finish of the V has to be smooth to get an accurate and repeatable reading.

The fact is as long as the wires are straight and within tolerance it doesn't matter who made them. It is up to the user to measure his wires or just blindly use them. I use a small SS wire brush to clean the threads before measuring but the surface is still irregular and the wires only read one spot. I have a set of triangles that I often use because they read over the entire surface of the V.

What I am saying is no matter how good your wires or set of triangles are the surface finish of the thread will determine how accurate the PD reading will be. So, discussing the quality of the wires is not as important as discussing the quality of the thread V surface.

Mcgyver
07-09-2010, 09:55 AM
It's quite interesting how defensive people get when somebody dares to question purchasing behaviour, as if it were a personal affront to their own egos. It probably says more about their personality than any slander I'd hope to come up with, even if that WAS my intent!

that's precisely the type of remark i see frequently from you that i think is guaranteed to piss people off. You claim its not your intent - if that's true maybe explaining why will help.

You loosely define a subset - "defensive people get when some dares questions..." Its clear in this thread myself, Nick, Robert maybe others would make the subset - anyone who's debated purchase criteria with you. But you don't say who its addressed to specifically, you leave it a slightly veiled insult. You use the word defensive which is judgemental and mildly insulting; if someone explains their reasoning, is that defensive? maybe, but its a judgement on your part and characterizing it as defensive is mildly insulting - who wants to be considered defensive rather than open minded?

Then you go on to state how this behaviour is driven by ego - any thinking man knows being driven by ego is a sign of poor character. Another insult. Then you cap it off by declaring their own behaviour reveals their character flaws far more effectively than you ever could. Wow.

Its insidious tossing the insult out like this, not addressed to anyone in particular..... but you don't need a graduate degree to figure out who you're thinking of. Like that scene in a movie where someone in a bar's insulting someone but not looking directly at them or using their name - what reaction does that usually produce and what happens next?

i don't mind being called out when deserving and i certainly don't claim to always be onside, so blast away man to man but these innuendos come across as far more offensive than a direct statement and imo don't serve you well

lazlo
07-09-2010, 09:58 AM
The fact is as long as the wires are straight and within tolerance it doesn't matter who made them. It is up to the user to measure his wires or just blindly use them.

That's the issue in a nutshell. How straight/round and on-size do you think the Chinese thread wires are for $6?

oldtiffie
07-09-2010, 10:22 AM
Originally Posted by Carld
The fact is as long as the wires are straight and within tolerance it doesn't matter who made them. It is up to the user to measure his wires or just blindly use them.

That's the issue in a nutshell. How straight/round and on-size do you think the Chinese thread wires are for $6?

Carl,

you are dead right - check them.

Lazlo.

Mine are not more than 0.0001" ( a "tenth") between highest and lowest in each size. I didn't bother to check them any closer as there was no need to.

The tolerances on most threads are that wide that for most shop-made threads I could use fencing wire.

If I were working to "guage" tolerances that is quite another matter as I'd be grinding the threads - not turning them, and as I'd be working within microns (ie micrometers = um = multiples 40 millionths of an inch).

If I were turning them with a lathe tool I certainly would not be using anything but fine ground HSS. There would not be too many here that could get the required angular accuracy or alignment anyway - so its all moot in most cases.

But as we are not working to "guage" tolerances, but the normal Classes A and B it really doesn't matter at all.

If I have tolerances and limits to use - I use them.

Richard Wilson
07-09-2010, 10:29 AM
Wow! Although I do know what these wires are for, I'm glad I don't own any and am unlikely to ever need them. Seems to avoid a whole pile of angst. I'll just stick with being rough, ignorant and happy.

Richard

pcarpenter
07-09-2010, 10:43 AM
Boy...this one sure did go on for a bit last night.

I wanted to address a couple of things that Mcgyver brought up. I do get that because you are measuring thread depth via angular distance, the need for greater precision in the wires is there. Also, as pointed out, the tolerances in most threaded fits far exceed any error introduced even by a a few tenths variation in thread wire thickness.

Far more important however was the fact that way early on, somoene mentioned that they had measured their Chinese thread wires and they were consistent within a tenth. Fair sample....one set? Probably not, but the point was still made that it matters not where they are made, only that they are precise enough for the job. Many folks seemed to be arguing that they were not (precise enough) based on country of origin, rather than actual measurements....in spite of the fact that someone had already introduced some real empirical data that said otherwise. This *is* whipping a dead horse to (try to) justify one's purchasing habits.

Me-- I have some really nice tools from famous makers...and some that are not and still do the job just fine. I don't even hesitate to make fun of the junk when it's really junk....but it's never safe to assume that all (fill in country of origin) made products fit that description. In my case it's an issue of practicality: Money spent on brand name thread wires that will not do the job any better than an import set is money I don't have to spend on something more critical.

I also understand that some HSM's need to work to high levels of precision on occasion. My question still stands. I mentioned that since many external threads (the things you measure with thread wires) are to be fitted to an existing internal thread, how does the average home shop guy make use of thread wires to get that job done? The answers I got were "make some plug gauges". Does anyone see the circular nature of that answer? If you could make the gauge to fit, then just cut the external thread to fit in the first place. It's still trial and error...and that potentially puts you well beyond the limits of measuring with cheap thread wires.

Edit-- adding to what Carl wrote above: I mentioned before that I had burrs far greater than a tenth that really mess with the levels of precision that some seemed to be talking about. Carl mentioned a wire brush and I agree. I have fairly limited thread cutting experience compared to many here, but another item that comes in really handy are the "thread restore" files. They are probably crudely made and are really designed around fixing a boogered up bolt, but I use them to quickly chase the threading pass I just made before trial fitting the mating female part. For those who don't know what I am talking about, they look like these: http://www.use-enco.com/CGI/INSRIT?PARTPG=INLMKD&PMPXNO=3011338&PMAKA=990-3074

Paul

oldtiffie
07-09-2010, 10:43 AM
That table seems to be quite off!
The optimum wire diameter is calculated by:

diam = P / (2 * cos(alpha/2))

With 0.5 mm pitch (metric; 60), the wire should be 0.288 mm. The standard (DIN 2269) says, that the thread should be checked close to the pitch diameter (I think you call it that way). Your table says 0.4572 mm (whatever that nonsense is to 0.1m accurate)


Nick

Nick.

I agree with what you say but the operative word is "should" (implies "option/ally") as opposed to "shall" (which is mandatory).

If the thread flank angle was perfect and if it were perfectly flat on the flanks, and if it was perfectly symmetrical about an axis normal to the thread pitch cylinder axis it would not matter where the "wires" contacted the flanks.

I suspect that when I "read between the lines" the Standard is "hedging its bets" and minimising as many errors as possible.

Tolerances and resulting limits are there to be used.

External thread classes of fit (ie 1A, 2A and 3A) and internal thread classes of fit (1B, 2B and 3B) are there to be used in what ever combination suits the job or application.

The tolerances and limits apply to the thread pitch diameter/s.

The classes of fit can be mixed as required.

Here are the specs and limits for a 1/2"-13-UNC thread:

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book_Fasten_P72-73_1.jpg

If we use the general shop case of Class 2A-2B fit with a basic pitch diameter of 0.4500" we find that the limits for the "nut" are 0.4565"/0.4500" which are 0.0065" apart (my "working allowance") and the limits of the "bolt" are 0.4485"/0.4435" which are 0.005" apart (my "working allowance").

Given that the "tightest" 2A-2B fit is between the smallest "nut" (0.4500") and the largest "bolt" (0.4485") the clearance is 0.4500 - 0.4485 = 0.0015".

Given that the "loosest" 2A-2B fit is between the largest "nut" (0.4565") and the smallest "bolt" (0.4435") the clearance is 0.4565 - 0.4435 = 0.013"

So the clearance range limits are 0.013" apart.

From that, I can't see that I should worry too much about a "thou" (0.001") here or there as regards either wire sizes or pitch cylinder diameter.

The rest is all in Machinery's Handbook.

Mcgyver
07-09-2010, 10:45 AM
Mine are not more than 0.0001" ( a "tenth") between highest and lowest in each size. I didn't bother to check them any closer as there was no need to.

The tolerances on most threads are that wide that for most shop-made threads I could use fencing wire.

If I were working to "guage" tolerances that is quite another matter as I'd be grinding the threads - not turning them, and as I'd be working within microns (ie micrometers = um = multiples 40 millionths of an inch).


the point is valid, that sans thread grinding, one can't take advantage of the limits of accuracy to which standards call for them to be made. It's unlikely I'd be doing something that would need better than a tenth (for those tuning in, a tenth on thread wire can be close to half a thou on the thread measurement).

and yes you can use any straight, round bit of metal....( drill rod might not be round)....but the point of a nice set of all the sizes that are straight, round, accurate and in a package is convenience. Before getting some I did use drill bits or music wire or whatever else i could find rummaging around the shop....how much fun is that? Convenience man! I also refuse to make my own surface plates.

John Stevenson
07-09-2010, 10:49 AM
Wow! Although I do know what these wires are for, I'm glad I don't own any and am unlikely to ever need them. Seems to avoid a whole pile of angst. I'll just stick with being rough, ignorant and happy.

Richard

Don't blame you Richard,
I have two sets, never use them but probably thread more parts that any ten people on this forum.
Just come in for a breather and cuppa doing some long M16 turn buckles with left hand and right hand threads on them.

Throw in the state of the thread finish and the fact that probably only two people can understand how to use them and read the chart they are one of these 'must have' tools that never gets used, a bit like a chocolate fireguard.
:D

oldtiffie
07-09-2010, 11:03 AM
Originally Posted by oldtiffie
Mine are not more than 0.0001" ( a "tenth") between highest and lowest in each size. I didn't bother to check them any closer as there was no need to.

The tolerances on most threads are that wide that for most shop-made threads I could use fencing wire.

If I were working to "guage" tolerances that is quite another matter as I'd be grinding the threads - not turning them, and as I'd be working within microns (ie micrometers = um = multiples 40 millionths of an inch).


the point is valid, that sans thread grinding, one can't take advantage of the limits of accuracy to which standards call for them to be made. It's unlikely I'd be doing something that would need better than a tenth (for those tuning in, a tenth on thread wire can be close to half a thou on the thread measurement).

and yes you can use any straight, round bit of metal....( drill rod might not be round)....but the point of a nice set of all the sizes that are straight, round, accurate and in a package is convenience. Before getting some I did use drill bits or music wire or whatever else i could find rummaging around the shop....how much fun is that? Convenience man! I also refuse to make my own surface plates.

Thanks Mac.

As we have got back to practicalities instead of theorising to "tenths" and "better"?? I will "get around" the need for "3-wires" in the average shop altogether. All that is needed is a single bit of drill rod (silver steel here in OZ, NZ and the UK) or a new drill shank - and we are away. All that is required is an outside diameter with a reasonable finish that is concentric with the screw (read: head-stock).

Its not new at all as I saw and was taught it and first used it to good effect 55 years ago.

What IS needed is an accurately ground and aligned screwing tool.

What it does do is eliminate that total PITA of trying to hold 3 wires in place accurately and then use a micrometer to measure accurately as only one accurately measured "wire" is required.

THAT is my aim and agenda!!!

I will cover it shortly - next day or so.

lazlo
07-09-2010, 11:18 AM
Mine are not more than 0.0001" ( a "tenth") between highest and lowest in each size. I didn't bother to check them any closer as there was no need to.

Amazing -- they don't look like they've ever been taken out of their pouch.

MuellerNick
07-09-2010, 11:23 AM
The answers I got were "make some plug gauges". Does anyone see the circular nature of that answer?

Do you ever read what others post or are you only repeating what is right from your personal limited perspective?
How can I make a threaded backplate that needs a tight fit? The lathe is 300 km from here.
How do I make an lens adaptor when the client simply doesn't want to send me his Linhof, Arri or Haselblad camera?

To oldtiffie:
No, not an 2A-2B fit, that's not what is wanted. Maybe you read the description, then think again.

There is also a very simple reason why it has to be measured at the pitch diameter. It reduces errors through an wrong angle. DIN/ISO exactly states the pitch diameter. Your standards may have a different degree of sophistication.
Maybe your first table is from some Chinese chopsticks, then it would explain everything. If it is from the Machinery's Handbook, I don't know what they smoke to get the idea to redefine DIN/ISO by their way.


Nick

Carld
07-09-2010, 11:25 AM
I guess you can throw me in the boat with John S, because I seldom use the thread wires or triangles. I have a collection of test nuts I use that I ran a tap through to be sure they are tight and close to a standard tap fit. If the nut is not tight on the tap and pull some metal I find another that will and add that to my collection. What I now regret is leaving my collection at work when I retired and had to start over.

Many times I have to turn the thread to fit a female part I have in hand. It really becomes a problem when I can't have the female thread to cut to but that is not a tale to tell here.

I use thread wires or triangles when I have to cut a thread to a specific PD and at that point I try to get as clean a surface finish as I can on the thread.

I agree with Nick that knowing how to make a thread to an internal thread you don't have in hand can be done but you have to trust the tolerance of the maker of the internal thread.

oldtiffie
07-09-2010, 11:27 AM
Originally Posted by Tiffie
Mine are not more than 0.0001" ( a "tenth") between highest and lowest in each size. I didn't bother to check them any closer as there was no need to.
Amazing -- they don't look like they've ever been taken out of their pouch.

Lazlo.

You are sounding like John Stevenson's echo (shadow??).

I can accept it from John as and when he said it, to which I replied that it was photoed as and when I got them, and he seemed to accept it - sort of.

If you want to be trite and snapping at my heels etc. then be my guest and go for it.

I've got better things to do than waste my time at "Play School" - I left it quite a while ago.

lazlo
07-09-2010, 11:45 AM
It's funny how these tool threads all evolve into the same pissing contest: one camp will jump into the discussion and insist that if you bought a non-Chinese tool you wasted your money, and the other camp insists that Chinese tools are junk. Inevitably someone from the first camp insists that they've measured their tool and it's "Spot on" or "within a tenth."

We've had that exact same pissing contest with coaxial indicators, Kurt vises, edge finders, Aloris toolposts, collets, 3D Tasters, spindle bearings ... Hell, I remember when Bob Warfield was criticized for posting a tool gloat about a gage block set, because it was claimed that a home machinist couldn't possibly have a need for that level of precision :rolleyes:

Live and let live.

oldtiffie
07-09-2010, 11:52 AM
.................................................. .......................

To oldtiffie:
No, not an 2A-2B fit, that's not what is wanted. Maybe you read the description, then think again.

There is also a very simple reason why it has to be measured at the pitch diameter. It reduces errors through an wrong angle. DIN/ISO exactly states the pitch diameter. Your standards may have a different degree of sophistication.
Maybe your first table is from some Chinese chopsticks, then it would explain everything. If it is from the Machinery's Handbook, I don't know what they smoke to get the idea to redefine DIN/ISO by their way.


Nick

Nick.

You sure don't need my approval to work as and as precisely as you wish.

I addressed the issues of "wrong angles" on several occasions. If they are there you will get a "correct" measurement over the wires but if any of those "wrong angles" are present then that "correct" reading at the supposed pitch cylinder may NOT be correct.

I would hope that with the degrees of accuracy you seem to be espousing that those "wrong angles" would have been eliminated for practical purposes during the pre-machining set-up and preparation phases.

"2A-2B" fit is a good fit for most work.

I am not aware that Machinery's Handbook sought to or actually did "redefine ASO/DIN".

That you don't like (or "approve"??) of USA and "non-ISO/DIN" standards does not make them wrong.

Just get used to it and/or learn to live with it.

pcarpenter
07-09-2010, 12:09 PM
Do you ever read what others post or are you only repeating what is right from your personal limited perspective?
How can I make a threaded backplate that needs a tight fit? The lathe is 300 km from here.
How do I make an lens adaptor when the client simply doesn't want to send me his Linhof, Arri or Haselblad camera?



Nick-- I got the point a long time ago....I would dare say that Haselblad camera's use a thread of fixed dimension and are accurately made to a published spec, with a published tolerance that lets you fit to that standard without a mating part. There thread wires come in pretty handy.
However, for the kinds of things that many of us do most often, we don't have the ability to rely on that sort of consistency. In the ideal world, we would measure the female part, and then use thread wires to measure the mating male part we are making until we have a fit of the proper type. My only point was that measuring those internal (female) threads is something that most of us home-shop types are *not* tooled up to do so we use the cut-and-try method.....which renders thread wires less useful....and extraordinary levels of precision in those thread measuring wires even less so.
Paul

dp
07-09-2010, 12:09 PM
The wire diameter optimalness comes down to a few simple needs. The wire must rest on the flanks of the thread, and the diameter of the wire must cause the circumference of the wire to project beyond the major diameter of the thread. That's all. There is no driving requirement the wires land on the PD of the thread.

The need for simplicity suggests that for a given measurement the three wires used should be the same dimension, +-0.0 - regardless of the diameter. This can be measured in the home shop to 0.0001 resulting in an adequate set of matched wires.

The formula for calculating the linear dimension across the three wires on a thread of known pitch is well known. This is why the optimalness of the wire diameter is unnecessary. The simple fact is the optimalness only allows us to use tables someone else has calculated and which are widely distributed. We can calculate our own tables and it is a trivial exercise.

Accepting the above as fact, and it is undeniable, an HSM bloke can assemble sufficiently matched wires to form wire sets, and to create tables from those wires to direct him to their use for thread pitches that interest him. This is not, by any means, rocket science.

http://www.euramet.org/fileadmin/docs/Publications/calguides/EURAMET-cg-10-01_Determination_of_Pitch_Diameter.pdf

It is also not outside the skill set of the typical HSM to fabricate for convenience 1 and 2 wire holders to make the use of the wires more convenient.

This same HSM will very quickly discover by measuring his threads at several points along the run that the precision is more immediately affected by quality of the thread flank finish and trueness of his tailstock than his wires. At this point he will likely say "wull, it fits'r, so it's dun".

oldtiffie
07-09-2010, 12:40 PM
Nick-- I got the point a long time ago....I would dare say that Haselblad camera's use a thread of fixed dimension and are accurately made to a published spec, with a published tolerance that lets you fit to that standard without a mating part. There thread wires come in pretty handy.
However, for the kinds of things that many of us do most often, we don't have the ability to rely on that sort of consistency. In the ideal world, we would measure the female part, and then use thread wires to measure the mating male part we are making until we have a fit of the proper type. My only point was that measuring those internal (female) threads is something that most of us home-shop types are *not* tooled up to do so we use the cut-and-try method.....which renders thread wires less useful....and extraordinary levels of precision in those thread measuring wires even less so.
Paul

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book_Fasten_P72-73_1.jpg

Paul.

That conundrum is of measuring the "nut"/"female" quite accurately is not so hard to solve at all.

It is remarkably simple. I will post the explanation with a sketch in the next several days.

I'd be inclined to use good quality "rolled" thread on a "bolt" of the same nominal diameter, thread-form and pitch as the intended "nut".

Once the "bolt" is measured - with 3 or 1 wire/s - it will determine where the pitch diameter is.

I will cover it with a sketch in the next several days.

If the bolt and nut were to be say a 2A-2B fit on a 1/2"-13-UNC thread (see the pic above) and if the pitch diameter of the "bolt" was say 0.4460" it would be in the 2B range.

The limits for the 2A nut would be highest of 0.4565 - 0.4460 = 0.0105" above the measured bolt pitch diameter and the lowest would be 0.4500 - 0.4460 = 0.0040" above the 0.4460" bolt pitch diameter.

The rest is fairly simple and will need the sketch.

This is the "other half" of the "3-wires using 1 wire" method that i learned a long time ago as mentioned previously.

This is just a variation of the common "shaft and hole" "limits and fit" and "tolerance" scenario.

Later.

lazlo
07-09-2010, 12:41 PM
The need for simplicity suggests that for a given measurement the three wires used should be the same dimension, +-0.0 - regardless of the diameter. This can be measured in the home shop to 0.0001 resulting in an adequate set of matched wires.

First, we assume a spherical chicken.

That's the problem -- any piece of wire is going to be +/- several thou on size and roundness. That's why thread wires need to be lapped in sets.

All this arguing to justify crapping on Nick's tool gloat... :(

oldtiffie
07-09-2010, 12:48 PM
The wire diameter optimalness comes down to a few simple needs. The wire must rest on the flanks of the thread, and the diameter of the wire must cause the circumference of the wire to project beyond the major diameter of the thread. That's all. There is no driving requirement the wires land on the PD of the thread.

The need for simplicity suggests that for a given measurement the three wires used should be the same dimension, +-0.0 - regardless of the diameter. This can be measured in the home shop to 0.0001 resulting in an adequate set of matched wires.

The formula for calculating the linear dimension across the three wires on a thread of known pitch is well known. This is why the optimalness of the wire diameter is unnecessary. The simple fact is the optimalness only allows us to use tables someone else has calculated and which are widely distributed. We can calculate our own tables and it is a trivial exercise.

Accepting the above as fact, and it is undeniable, an HSM bloke can assemble sufficiently matched wires to form wire sets, and to create tables from those wires to direct him to their use for thread pitches that interest him. This is not, by any means, rocket science.

http://www.euramet.org/fileadmin/docs/Publications/calguides/EURAMET-cg-10-01_Determination_of_Pitch_Diameter.pdf

It is also not outside the skill set of the typical HSM to fabricate for convenience 1 and 2 wire holders to make the use of the wires more convenient.

This same HSM will very quickly discover by measuring his threads at several points along the run that the precision is more immediately affected by quality of the thread flank finish and trueness of his tailstock than his wires. At this point he will likely say "wull, it fits'r, so it's dun".

Good post Dennis.

I agree with you as regards the theory, but I am not sure that a lot have the maths skills to transpose the formula as required.

It is just a bit - not much - above "Shop Maths 101".

I'd transpose it to solve for the perfect wire (diameter) then get the nearest available wire/s that would project above the "bolt" outside diameter", then use that value and insert it into the formula to solve for the distance over the wires for that wire diameter and that pitch diameter. I would then solve for my limits for the particular "Class of Fit".

Its just made for and is much easier in CAD.

Mcgyver
07-09-2010, 01:21 PM
The answers I got were "make some plug gauges". Does anyone see the circular nature of that answer? If you could make the gauge to fit, then just cut the external thread to fit in the first place. It's still trial and error...and that potentially puts you well beyond the limits of measuring with cheap thread wires.


Paul, I'm missed something if the approach seemed circular....many times its challenging because of size, location etc or not wanting to disturb the parts in the lathe to use trial and error to fit the male thread to an existing female...plus some instances of trial and error end in error....depending on the complexity of the piece, that could be painful! Trial and error doesn't tell you how much more to take off even when the parts can be brought together for a trial.

The other thing is, for me anyway, any discussion of thread wires prejudices things to highest class of work....in other words like you i do trial and error all the time; the thread wires come out when it really matters....so talking about using thread wires is talking of very small percentage of what i do, lest anyone think i approach making a say a machinist clamp as if it was a hasselblad. Things become a bit hypothetical and not representative of day to day tasks

The scenario I was thinking of was you have an existing female thread requiring some very high class small tolerance fit. Lets say the bit has been done on the T&CG or better surface grinder with some super accurate fixture so angle isn't a source of error. Not knowing the internal thread's class size or tolerance the approach i tried to suggest was using gauges to figure out exactly what the internal thread was. One could turn gauges in say brass so there wouldn't be galling that would just go with the slightest bit of force - might take a few attempts or maybe even something with steps to it. By gauge i was thinking something that exactly mated with the subject so it could be used to measure the subject, not the typical go/no go which is great for inspection but as Nick pointed out doesn't measure.

Measure the gauge with thread wires and you've measured the female thread. For whatever ever class you're doing you can then use the wires to turn its mate in go without any finger crossing or need to dismount the work or bring the mate to the lathe (which might not be possible)

As I say not your every day occurrence, I just wanted to show how thread wires could be used to measure the internal thread to get desired fit

leesr
07-09-2010, 01:22 PM
at the end of the day all that matters is do we have the the right tools to do
the right job.

Pissing in the wind doesn't help.
be constructive in these discussions.

pass on your experience and be done with it.

you can lead a horse to water but yo can not make the horse drink it.
every one has his or her experience, bottom line what gets the job done.

there's more than one way to skin a cat? yes.
Take care All
Leesr:eek:

Mcgyver
07-09-2010, 01:22 PM
duplicate






.

dp
07-09-2010, 01:39 PM
First, we assume a spherical chicken.

That's the problem -- any piece of wire is going to be +/- several thou on size and roundness. That's why thread wires need to be lapped in sets.

All this arguing to justify crapping on Nick's tool gloat... :(

I'm not arguing. Explaining a principle is not arguing. Wire roundness can be tested. If the wire is a sewing needle then the roundness will be the least of your worries. It will be masked by thread flank finish and affects of errors in tool shape, height, and alignment. An HSM can do very well with home-made wires and if he creates his own tables he can use a single three-wire set for a wide range of threads and with good accuracy.

I've no reason to crap on Nick's tool gloat and have congratulated his good luck. Sometimes your theatrics are a bit over the top.

Mcgyver
07-09-2010, 01:39 PM
Amazing -- they don't look like they've ever been taken out of their pouch.

ah ha, an important element of the truth table is revealled!

They've never failed me, they're all i need, I've never noticed a difference between them and the Starrets, they're more that accurate enough for anything i've ever used them for etc become absolute positions of fact :D



j/j OT, couldn't resist

lazlo
07-09-2010, 02:42 PM
I'm not arguing.

I wasn't referring to you Dennis -- just that someone posts a great deal and it creates a 12 page storm because people think Nick paid too much or doesn't need the accuracy.
Pretty sad.

BTW, I don't think an HSM'r is going to find any source of wire around the shop consistent enough to make his own set of thread wires. That's why thread wires are lapped in sets.

pcarpenter
07-09-2010, 03:09 PM
I wasn't referring to you Dennis -- just that someone posts a great deal and it creates a 12 page storm because people think Nick paid too much or doesn't need the accuracy.
Pretty sad.


I think there are really two different conversations going on here: One about necessary precision in thread wires and the second about Nick's tool gloat....with the second having fallen into the cracks about 50 posts ago. Actually, what started the storm was the allegation that thread measuring wires made in China were *inherently* less accurate without...no...actually in spite of...some anecdotal indications from owners of same that they were in diameter within a .0001". This seems to imply that the higher-priced brand name wires offered even more precision and that that precision was useful and that's where the storm takes off....

Me....I am an engineer....I love precision, and I love really well made tools, but there's precision that's applicable and that which transcends (most but not all) real-world use. These are pieces of wire so spend as much of your tooling budget on them as you want. Certainly $26 US is not ridiculous and I like the wire holder! Maybe I should have said that first thing off the bat:rolleyes: .

Paul

clutch
07-09-2010, 03:52 PM
Nick,

I'm having troubles visualizing how that holder works. The pictures on the website are too small.

I've never truly mastered the art of hanging on to thread wires and measuring the wires over threads. I get it done, the threads fit but it is awkward.

Some of your detractors are seeming to say, that any wires will do for the work they do. I'm not saying skills they have, just the work they do. I sure don't want to insult anyone here with far more skill than I have.

If it was a gloat for you that is all that matters.

Clutch

BobWarfield
07-09-2010, 04:11 PM
Nick's love of these Teutonic tools maybe just turned the gloat into a sneer at all things Chinese, LOL.

I had a chance at a related gloat. I got a very large box of pro quality go-no go gages off eBay one time. I bid $1 on a lark and got them for $39. It had to cost more to ship as I could hardly lift the box.

It's not gloatable though because while the gages are fine (perfect, in fact), I never have used them. Sometimes I look at them and think they're of more value for the fine steel they're made of!

Cheers,

Bob warfield

tdmidget
07-09-2010, 04:16 PM
Just to clear up something thats been repeated here. Thread wires are not "lapped".
They are centerless ground.

MuellerNick
07-09-2010, 04:18 PM
I'm having troubles visualizing how that holder works. The pictures on the website are too small.

There is a metal plate with a hole that is a tad bigger than the micrometer's diameter. Behind that plate is a plastic piece. It first holds the wires in place allowing them to shift a bit sideways to align to the thread. Furthermore, the plastic part holds a spring (I guess it is almost round, but pressed to be a bit square, maybe looks a bit like a C-clip). This spring slips over the micrometer and prevents the complete contraption to fall off.


I think it is best if I return the set to the seller telling him that he asked much too little and excuse myself being so unpolite not to tell him. With that money I'll buy the superb Chinese set and a piece of clay as punishment.
Next step will be selling the Haas lathe, the MAHO mill, the Deckel mill, the Myford cylindrical grinder, the Walter T&C grinder, the EWM TIG, the Rehm MIG/MAG, all the Fein handtools, the Mitutoyo and Mahr metrology stuff, the Planolith surface plate, the BIAX ... and then place an order at Horror Fright.


Nick

Mcgyver
07-09-2010, 04:35 PM
how much you asking for the Biax?

MuellerNick
07-09-2010, 04:41 PM
how much you asking for the Biax?

A genuine Chinese wire set (western clones and sets with calibration data not allowed) would be a fair price.

Nick

lazlo
07-09-2010, 04:50 PM
Just to clear up something thats been repeated here. Thread wires are not "lapped".
They are centerless ground.

The cheap ones are. I have a set of Van Keuren thread wires, and they're lapped:

* Calibrated within .000005 of the calibrated size on the label
* Thread measuring wires are within .000020" of best wire diameter for specified tpi (threads per inch)
* Roundness within .00010
* Taper does not exceed .00010"
* Standard 2" lengths
* Packaged 3 wires in a screw top vial
* Minimum hardness of RC 62.5
* Surface finished lapped, 1 MU AA
* Exceeds Federal specifications ASME/ANSI B1.2 and B1.6M
* Free NIST certificate of accuracy

clutch
07-09-2010, 04:51 PM
comment deleted

Clutch

John Stevenson
07-09-2010, 05:40 PM
The cheap ones are. I have a set of Van Keuren thread wires, and they're lapped:

* Calibrated within .000005 of the calibrated size on the label
* Thread measuring wires are within .000020" of best wire diameter for specified tpi (threads per inch)
* Roundness within .00010
* Taper does not exceed .00010"
* Standard 2" lengths
* Packaged 3 wires in a screw top vial
* Minimum hardness of RC 62.5
* Surface finished lapped, 1 MU AA
* Exceeds Federal specifications ASME/ANSI B1.2 and B1.6M
* Free NIST certificate of accuracy

And used to check the thread fresh off a lathe that has no NIST accuracy on it's leadscrew when it was new.

Now it's umpteen years old and thrown out by industry as being bolloxed it's open house.

.

John Stevenson
07-09-2010, 06:00 PM
I'm fed up with their crap. They can sell it to the bargain-hunters so they later can wine about losing jobs. I think it's more clever to support local (or at least western + Japan) economy.


Nick

~???????????

Ok so you live in Germany, does supporting Swiss, Austrian, British and Japanese jobs help the German economy.

What's the difference between Japanese and Chinese ? it's still an outside market force that jobs are going to.

Did you read that before you posted it ?

.

PeteF
07-09-2010, 07:26 PM
i don't mind being called out when deserving and i certainly don't claim to always be onside, so blast away man to man but these innuendos come across as far more offensive than a direct statement and imo don't serve you well

You've got some nerve buddy! Who do you think you are? Who are you to TELL me how I should write? I don't even know you. Are you of a similar habit that you wander up to strangers in the street and tell them how they should dress as you find their dress sense offensive? Not having used them, I asked a series of questions about why thread wires need to be that accurate, and carried on with a clearly controversial theme of questioning why some people will jump to conclusions about product quality based on brand and/or country of origin without any other evidence to support that conclusion. They were asked in a controversial manner, as will typically be done when playing the "devil's advocate", and I clearly stated that at least twice. If you don't like the questions or you don't like the way I ask them then don't read my posts. Simple. Most BBs have an ignore function, I presume this one shares that feature, why don't you use it and place my name in there instead of your continued self-serving arrogant swipes at me?

Edit: On further thought, this is what "devil's advocate" means "a person who expresses a contentious opinion in order to provoke debate or test the strength of the opposing arguments" or alternatively try http://en.wikipedia.org/wiki/Devil's_advocate if you still don't understand!

PeteF
07-09-2010, 07:40 PM
What's the difference between Japanese and Chinese ?

That's possibly an ironic question there John. I remember as a kid the very same reaction to Japanese goods as we currently experience with Chinese goods; cheap Japanese junk. Made in Japan = crap. It's funny how the wheel turns ;)

oldbikerdude37
07-09-2010, 07:47 PM
That's possibly an ironic question there John. I remember as a kid the very same reaction to Japanese goods as we currently experience with Chinese goods; cheap Japanese junk. Made in Japan = crap. It's funny how the wheel turns ;)

I said the same stuff about Japan years ago but changed my mind after 20 years, they make great stuff. Now china is pumping out all kinds of goods but I hold firm they make the best plastic laundry basket I have ever seen.:p

Mcgyver
07-09-2010, 08:13 PM
deleted...no point in continuing this

oldtiffie
07-09-2010, 08:18 PM
Originally Posted by lazlo
The cheap ones are. I have a set of Van Keuren thread wires, and they're lapped:

* Calibrated within .000005 of the calibrated size on the label
* Thread measuring wires are within .000020" of best wire diameter for specified tpi (threads per inch)
* Roundness within .00010
* Taper does not exceed .00010"
* Standard 2" lengths
* Packaged 3 wires in a screw top vial
* Minimum hardness of RC 62.5
* Surface finished lapped, 1 MU AA
* Exceeds Federal specifications ASME/ANSI B1.2 and B1.6M
* Free NIST certificate of accuracy


And used to check the thread fresh off a lathe that has no NIST accuracy on it's leadscrew when it was new.

Now it's umpteen years old and thrown out by industry as being bolloxed it's open house.

.

Dead right John.

It is probably the most important factor of all. I'd like to know how the average HSM-er would or could check that accuracy of the lead-screw to the levels of accuracy that are inferred in some of the comments here.

So let's take a look at it all.

Here is the tables for the nominal pitch cylinder diameter:
http://i200.photobucket.com/albums/aa294/oldtiffie/Screw_threads/3-wire3.jpg

First of all, here are the common thread forms. I will stay with the common 60 degree threads - ISO/DIN and Unified/UNC/UNF as they are substantially the same:

http://i200.photobucket.com/albums/aa294/oldtiffie/Screw_threads/Screw_threads2.jpg

Note the outside diameter is less than the nominal diameter of the screw/bolt and also the position and size/diameter of the pitch cylinder diameter.

Here is the data for the 1/2"-13-UNC thread as posted previously:

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book_Fasten_P72-73_1.jpg

Everybody seems to be using the "3-wire" tables to get the nominal pitch diameter to the n^th degree of accuracy - and it isn't even needed or used in most cases as it is just on the lower size limit for the nut/hole and the upper limit for the A3 bolt.

The nominal pitch diameter is outside the limits for class B1 and B2 bolts and so despite all the worry and super accuracy it is all wrong.

The measurement over the wires has to be adjusted to suit the limits of the particular bolt.

Note, as I said earlier, that the limits of the Class 2A bolt are from 0.4485" to 0.4435" below/under the nominal 0.4500" pitch diameter. Note too that there is 0.005" "play" between those limits so super accuracy is not needed at all. If I were to aim for the mid-point of the tolerance zone my limits would be 0.4460 +/- 0.0025" which is heaps to "play" with.

Too many here get too "wound-up" and "anal" about so-called "super accuracy" with 3-wires etc.when they are quite wrong but not only that the classes of fit are pretty "slack" really and are like a dick in a shirt-sleeve.

I strongly advise and suggest that many here need to and should read, digest and understand the real difficulties of using the 3-wire method as well as the accuracies needed for "die" and "guage" work as at
Machinery's Handbook 27:
- page 1897: "Measuring Wire Accuracy";
- page 1897: "Measuring or Contact Pressure";
- page 1922: "Measurement of Thread Ring Guages";
- page 1917: "Standards for ANS for GO, HI, LO Thread Guages";
- page 1787: "Limits and Fits";
- page 1793: "Limits of Sizes"

etc.

Note too how very similar it all is to the standard "Basic Hole" tables of "Limits and Fits" (which all too many ignore or disregard or just don't (or can't?) use.

http://i200.photobucket.com/albums/aa294/oldtiffie/Limits_and%20_Fits/Limits_and_Fits2.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Limits_and%20_Fits/Limits_and_Fits1.jpg

I will discuss ditching the 3-wires for a single wire as well as not having to use wires at all.

Later.

PeteF
07-09-2010, 08:47 PM
was only trying to help, i took you as sincere that you weren't trying to offend, if you don't want to offend but do, well isn't help a good thing?

i see progress is being made though; now your confronting man to man rather than hiding behind ambiguous insults

lighten up, take a chill pill

:)

Ok, well here's MY observation for you then, no veils here my friend. You are coming across as an egotistical, arrogant twat. Thanks for your "help", how good of you, but there's basically not been one post you've directed to me that hasn't smacked of arrogance. Even when it appeared you were holding out an olive branch, the insincerity was confirmed when you just couldn't help yourself but take a parting shot as you left with a smart-arse (and incorrect as it happened) comment about my knowledge of the wire measuring system.

If you choose to see yourself in the position of my generalisations well that's your business. But, once again, I'm not here to respond to pointless trolls. I have zero interest in going "man to man" as you seem so enthused about. Even though at the moment I have nothing better to do with my time, I'm sure I can think of something better than responding to your continued attempts to stroke your own ego by bringing others down. If you want to talk, heaven forbid, about machining on a machining BB (who would have thought hey), then do so. Because I'm quite sure I'm not the only one who has no interest in reading this sort of crap, and I have no intention of inflicting it on the rest of the people here by responding to continued pointless trolls. Over to you so you can get the last word and can scuttle off, chuffed with yourself that you "won" the argument.


i see progress is being made :rolleyes: holy cow mate, what an ego!

oldtiffie
07-09-2010, 08:57 PM
For PeterF.

Peter,

are you any better informed about "3-wires measuring" and its applications and limits?

If I've missed any pertinent points or need to elaborate or clarify any issues, please let me know - here.

I am really interested in your opinion as you are relatively new to the "3-wires" bit, and have an open and inquiring analytical mind(-set) where-as some others cannot or will not shift or be shifted from a fixed position or outlook on it.

PeteF
07-09-2010, 09:15 PM
Yes thanks Tiff, you've gone to quite a lot of trouble, particularly with the photos and scans. You obviously know I like pictures :D I think there's others here who have also gained a lot from it too, and helping others with their machining endeavours is what this type of forum should be all about.

Pete

Edit: Incidentally Tiffie I noticed one of your scans was from the Little Black Book. I would have to seriously say, barely a day goes by when I don't look up something in that book, it's an absolute gem. I must admit I've never been a big fan of the Machinery's Handbook when it comes to threads. Maybe it's just the older issue I have, but I find it doesn't cover metric threads very well at all. Just my 2 cents on that though

aboard_epsilon
07-09-2010, 09:33 PM
Well my experience of thread cutting is very limited ..but I've done a bit.

Get the tool perfect .....cut the thread ....you are sure it's perfect ...but the thread... it ain't ..the nut wont fit...cause no matter how hard you try to get a perfect tool ..and use a good lube....and run up and down in the same place many times with no cut on it.......youre left with tiny burrs on the job......you file the tops of the threads ...and wire brush the threads.and the nut then fits great.

So how the hell do the thread wires come in ...and at what stage ...when you go through that above ..im sure they will work great with brass ..i seem to be able to thread brass without any bother ..and no filing or wire brushing.

My solution ...is to cut 9/10ths of the thread then run a split die up and down it ...then you have something as accurate as the die...and as tight a thread or loose as your choosing.

or use a proper insert tool with the proper thread form.

if you use the right tool .....then where do the wires come in ...your tools perfect ...and should cut a perfect thread then....so what else can you do replace your perfect threading tool ..so it conforms with the wires...i think not .

Another thing ......with these wires, when in use...i bet you're bouncing a couple of hundred watts of light on the job ...and using a magnifying set up ..squinting to see what your doing ..time consuming ...the novelty of them would not take long to wear off with me ...and they would be consigned to the cupboard ..or sold on ebay to at a vastly inflated price to some other sad chap ...who also probably owns several unused pantograph engravers and a useless die filing machine :D

all the best.markj

J Tiers
07-09-2010, 10:51 PM
More random points........

1)
Thread wires, in my case yes, chinese P-D wires, now supplemented by a set of actual Pee-Dee brand ones (estate sale special)........... Well they seem to allow me to make threads that are closer fitting and have a lot less shake than the method of "get a nut from the bin".

I have made special-purpose micrometers (which I won't claim great accuracy in the microns for, but which performed their function accurately enough), and other items which "needed" close fit threads, and I have made stuff where I WANTED close fit threads, and when I knew the female thread size, and used wires in measuring, the threads fit the way I wanted them to.

So I reckon they are useful..... If I ever make some highly accurate 2 or 3 tpi threads, the Deltronic pins I have may be handy, otherwise most are too big for thread measuring, they are better as size standards.

2)
due to the angles involved, accurate wires, past the mere 'tenth" level, are good, since the inaccuracy of the wires gives something like 3 x the error in pitch diameter, PER WIRE.

So, assuming my rough geometrical approximation is correct, and the wires are all 3 undersized by a tenth, the total error in pitch diameter will be around 0.6 thou.

3)
For Pete, and others who don't like to see "blanket" dumping on chinese goods....................

In many cases, the idea that chinese is equal to lower quality comes from experience. The error is generalizing it to ALL production, but NOT in assuming that chinese goods may have serious flaws.

I have had the delicious experience of checking over chinese samples of products that were made here, and moved to china.

The range of flaws in a product when full prints, bills of exact materials, test procedures , etc were supplied, was astounding. For instance parts substitutions, where in one case 50 volt capacitors were substituted for 200V types, proving by their immediate failure that the sample units were almost certainly never tested, despite the test sheet.

In other cases, production units had a different circuit board layout, with a change made which actually caused a short directly across the output when a certain jack was used.... NOT present on the US version, NO explanation why the change was made with no approval.

And, of course, fine workmanship like this screw from an X-Y table....... the rough part at the left is the bearing.....

http://img.photobucket.com/albums/0803/jstanley/chinlead.jpg

Add in poisonous medicines, poison toothpaste, adulterants routinely put in animal feed to fake out the tests, plus other lovely items, and there is AMPLE reason to be suspicious and cautious with "generic chinese goods".

There isn't a reason to dump on a particular item, unless you know it fits the mold of the above....... made quick and cheap to be sold at a low price.

Even low price does not guarantee badness..... There is such a thing as a "loss leader", and it costs very little to make things in china still. I saw a figure that it costs about 42 CENTS US to print and put together a hard-back book... one that you will buy for $20 or even more at the book store.

There is a decent chance that good money could be made selling that book for $5, but then it would be "cheap chinese books".........................;) :rolleyes: :D

tdmidget
07-09-2010, 11:55 PM
The cheap ones are. I have a set of Van Keuren thread wires, and they're lapped:

* Calibrated within .000005 of the calibrated size on the label
* Thread measuring wires are within .000020" of best wire diameter for specified tpi (threads per inch)
* Roundness within .00010
* Taper does not exceed .00010"
* Standard 2" lengths
* Packaged 3 wires in a screw top vial
* Minimum hardness of RC 62.5
* Surface finished lapped, 1 MU AA
* Exceeds Federal specifications ASME/ANSI B1.2 and B1.6M
* Free NIST certificate of accuracy

Maybe you could explain to us how one would lap a wire under .020 in size and have any degree of roundness. I don't think you even know what lapping is. There is NO machining process that produces better circularity and less taper than centerless grinding.
If you had a wire that was Rc62.5 it would shatter when dropped or likely handled in the smaller sizes.
Nowhere on their web site does Van Keuren make the claims for lapping or hardness.
Their callouts for taper, finish and circularity are easily met by centerless grinding. They don't even call out for size beyond nominal, furnishing a calibration instead. Their web site calls for a finish of 2 Mu even on their grand master sets.

http://www.kennametal.com/images/pdf/products_services/metalworking/VanKeuren_AD06-30_catalog.pdf;jsessionid=RFRVYKDKYULGZLAUCYOSFEVM CQFB0IV0


Yeah a centerless can do it:
http://www.royalmaster.com/HiAccuracy.html

Now assuming you have all this accuracy in wires, when you put them on the part and measure, how much accuracy do you have? They are no better than the mike you measure with.

lazlo
07-10-2010, 12:01 AM
Maybe you could explain to us how one would lap a wire under .020 in size and have any degree of roundness. I don't think you even know what lapping is.

You're probably right -- Van Keuren must be lying :rolleyes:


There is NO machining process that produces better circularity and less taper than centerless grinding.

Uh, no. Centerless grinding always leaves a 3 lobed cylinder, which is why plug and go/no-go gauges are always lapped after centerless grinding.

Mcgyver
07-10-2010, 12:12 AM
Maybe you could explain to us how one would lap a wire under .020 in size and have any degree of roundness. I don't think you even know what lapping is. There is NO machining process that produces better circularity and less taper than centerless grinding..

just a guess but maybe like they lap roller bearings.... these
guys say they lap them, are you saying they centerless grinding them to 20 um accuracy?

i thought centreless was prone to lobing, but I could be wrong, i've not limited cylindrical/centreless experience.

http://www.westportcorp.com/gages/thread_plug_gages/threadwires.htm

J Tiers
07-10-2010, 12:13 AM
Robert:

The catalog, or the one findable at PMC Lonestar, actually does not anywhere say they are lapped........

They are calibrated per set, but the wires are guaranteed within 10 millionths of the best size.

Somehow I don't think there will be any problem with the Van Keuren wires, whether they are lapped or generated some other way.

McGyver:

Westport says theirs are lapped, BUT NOT FOR SIZE, just for surface finish.

lazlo
07-10-2010, 12:17 AM
The catalog, or the one findable at PMC Lonestar, actually does not anywhere say they are lapped....

I have the paper brochure from Van Keuren, from 30 years ago. They went out of business and Kennametal bought the name, but any high-quality thread wires (or plug gauges) are lapped to remove the tri lobes. Richard Moore has a couple of pages about it in Foundations.

http://www.westportcorp.com/gages/thread_plug_gages/threadwires.htm
http://i164.photobucket.com/albums/u15/rtgeorge_album/threadwires.png

Bottom line, you're not getting straight/round thread wires for $6... The circular argument is hilarious though:


Nick gets a great deal on a set of precision thread wires
John claims he was ripped off
Several posters point out that precision thread wires are carefully produced plug gauges that are vastly better than the Chinese versions
Chinese thread wire owners claim that Nick doesn't need that much precision


:)

J Tiers
07-10-2010, 12:27 AM
it STILL says "surface finish lapped"....... which is different from lapped to correct form etc........

For $6 not round? really?

Well, the Van Keuren are not round either.....

The difference is in how "not round" the "not round" is, and what significance that has.

Someone commented that the MICROMETER is an important part of this. to which I would add the OPERATOR of said micrometer. it's a known fact that different people can get a difference of several tenths with the same mic and same piece.

now we get to talk about temperature........ or we get to mention it, and it's effects on measuring, while the "all-for-precision" HSM holds teh mic in his (literally) hot little hands while he strives to get a "perfect" reading, as teh reading keeps changing on him........

So, the "goodness" of the Van Keuren, or Westport, etc, wires is largely a guarantee that at least THEY will not be the issue..... except in certain cases of real industrial QC departments, at constant temp and good precautions used against error of all sorts. Not to mention that their mics may read to a "tenth of a tenth".

dp
07-10-2010, 12:29 AM
Bottom line, you're not getting straight/round thread wires for $6...

A person would have to actually measure the wires to prove it. Having lapped a telescope mirror to an extreme degree of accuracy, I can verify there are rather simple optical methods to demonstrate there are or are not lobes on $6.00 wires.

lazlo
07-10-2010, 12:31 AM
it STILL says "surface finish lapped"....... which is different from lapped to correct form etc........

OK, so here's Van Keuren's description of why they lapped all their cylindrical gauges (including thread wires), from an old brochure. There's a section on how odd-sized lobes make the plug gauge effectively oversized (Richard Moore's description). You decide if the "peaks and valley" are the three lobes from a cylindrical grinder:

http://www.gagesite.com/documents/Metrology%20Toolbox/Plug%20gaging%20of%20holes%20by%20the%20Go%20NoGo% 20method.pdf


Gages produced by grinding will have a surface consisting of peaks and valleys. When such gages are inserted they will be subject to rapid wear due to the ease with which the peaks are abraded.

This wear may immediately eliminate the entire tolerance of the gage and make it undersize. A very smooth surface not subject to rapid wear is obtained by lapping the gage. Lapping removes the peaks and produces a smooth wear resistant surface and a long gaging life.

As shown in Figure 1, an odd lobed gage will have a greater effective diameter than any two point measurement could indicate. There are several other methods of assessing roundness which may yield different readings under different conditions. No matter how measure, however, it is good practice to restrict out-of-roundness to a maximum of 50 per cent of the gage tolerance."


...and a random citation from the 'Web, which looks borrowed from Machinery's Handbook:

http://its.fvtc.edu/machshop2/operations/3Wiremeas.htm

"The three-wire method uses three lapped and polished wires and a micrometer to measure the pitch diameter of the thread(Figure 15-2-2). "

tdmidget
07-10-2010, 12:41 AM
QWhy are westports claims different than the manufacturer?

The reason for the angled workrest or "blade" in centerless grinding is to eliminate the 3 lobe effect, which occurs on a flat workrest.

Did you not read the Royal master website? These tolerances are easily met with centerless grinding.
Again, tell me how you "lap" an OD smaller than .020.

Lazlo have you ever run a centerless grinder? Ever seen one? Lotta talk and little knowledge.

lazlo
07-10-2010, 12:44 AM
Lazlo have you ever run a centerless grinder? Ever seen one? Lotta talk and little knowledge.

I have a punch grinder which I use a lot, so yes. But I gather you've never used a lapping machine, since you didn't know that most plug and pin gauges are lapped?

tdmidget
07-10-2010, 01:44 AM
Yep, seen and run lapping machines. But I've never seen one for other than flat surfaces or IDs. I don't know what your "OD Lap" looks like but I cannot visualize any way to actually lap an OD. Again centerless grinding will produce the roundest, straightest parts possible. No "lapping" required. Why would anyone add an unnecessary operation?
Did you not look at the Royal Master site? Did you see the tolerances held routinely?

Regarding:

http://its.fvtc.edu/machshop2/operations/3Wiremeas.htm
"The three-wire method uses three lapped and polished wires and a micrometer to measure the pitch diameter of the thread(Figure 15-2-2)."
Lapped AND polished? Seems a bit redundant. Are we talking lapping or polishing here? Again I am waiting on that OD lapping tool.

MuellerNick
07-10-2010, 01:56 AM
Ok so you live in Germany, does supporting Swiss, Austrian, British and Japanese jobs help the German economy.

Shure it does. There is fair trade between those countries. They have about the same wages. They don't steal patents or designs.

It is a give and take, not just a one way road.


Nick

dp
07-10-2010, 02:00 AM
Shure it does. There is fair trade between those countries. They have about the same wages. They don't steal patents or designs.

And you have no balance of trade disputes?

MuellerNick
07-10-2010, 02:15 AM
And you have no balance of trade disputes?

I guess yes. But it seems we don't have to discuss about people's most basic rights.


Nick

oldtiffie
07-10-2010, 04:38 AM
Nick.

I have completed the calculations for the measurements over the 3 wires for the three different Pitch Diameters - the "standard" as well as those at the high and low limits for the 2A bolt for the 1/2"- 13 - UNC thread referred to previously. I used the wires and the tables in my set of wires that I posted earlier.

I will tidy it up and post the computations and figures later.

All (the three) measurements are over the same set of three wires as I guess you'd expect.

There is - as before - 0.005" between the limits so there is plenty to "play" with.

This is for a standard 2A bolt which is an everyday item.

Of course the limits will be much closer for a HI, LO or NO GO thread guage/s - as expected.

If I were you, I certainly wouldn't get rid of that very good set of wire guages yet!!!

MuellerNick
07-10-2010, 05:25 AM
This is for a standard 2A bolt which is an everyday item.

If I would make everyday items, I still go for the it-fits--that-nut-so-it's-ok. And I won't change that procedure, just because I can measure it much finer.
I also don't mike every lousy bolt to 0.001mm just because I can.
I don't grind everything to dead on diameter and 1m cylindricity over 200 mm just because I can (and it's a pain and more luck than wishdom).

If a caliper is good enough, I use it.


Nick

JCHannum
07-10-2010, 07:54 AM
It is interesting to note that Mcgyver's Westport link offers a 24 page book on the standards for measuring thread measuring wires. I doubt the Happy Elephant Thread Wire and Fortune Cookie Company LTD has a copy handy;

http://catalog.asme.org/Codes/PrintBook/B89117_2001_Measurement.cfm

I have a 1945 Van Keuren catalog stating their thread measuring wires, and other gages are lapped. It further includes the then current Bureau of Standards specifications for measuring wires. It is quite detailed, and I will not attempt bore you with endless scans of it, but it even includes the contact pressure to be used when measuring thread wires. Threads with 60*, finer than 20 pitch 16oz, 20 pitch and coarser 2-1/2#; wires for 29* threads, 2-1/2#. They are measured over a 0.750" cylinder.

gnm109
07-10-2010, 10:26 AM
Hi!

Have to tell this:
Was at a second hand tool dealer today. Besides a bunch of this and that and 5 touching prisms (used, they need rescraping) I got a complete box of measuring wires. They are used for measuring the major diameter of threads. AKA "3 wire method".
Saw the box and asked the boss how much. "Umm, don't know. Wait ... no, price is not on the box. 20.- (about $26)". "OK, I take then". Then he asked what it is used for. :D
I really was close to pissing my pants. The set was unused. Price for a single pair is 80.- . The set is complete and has 18 pairs. Makes about 1400.-

Think I can't sleep today because of that deal.

Don't ask for the dealer, I'm in Germany and am not allowed to tell anyhow.

Nick


Whenever you get a windfall such as this, you are required to share it with us. Didn't you read the agreement when you registered? LOL

I love getting things like that. It happens now and then, especially at garage sales.

RobbieKnobbie
07-10-2010, 12:46 PM
Just a couple quick observations/questions now that this thread has reached (gulp) sixteen pages...

1. did anyone notice that in the very first post Nick said that the wires were for measuring MAJOR diameter and not PD? I think pointing that out makes my pee go at least two feet farther than anyone else here.

2. How does buying tools... ANY tools... from a second hand shop help any nation's economy? I've purchased several Starrett mics at auctions, but not one cent of my bid went to Athol, Mass.

3. I worked in a job shop for ten years while putting myself through college at night, I then got a job at a plant that made nothing but fasteners for the Aerospace/Defence/Power industries... Boeing, Airbus, Pratt, GE, Rolls and so on. All we made was nuts and bolts... some of which ran into the thousands of dollars PER BOLT. It was/is a large operation, some 1200 workers between 3 shifts. In the six years there and the ten years before that I had never ONCE used/seen used/ or even seen a set of thread wires. Sure, I used them in my apprenticeship, but as far as real-world usage, nope. Not once.

Our threads were inspected every which way to sunday, by our own inspectors, customer reps, even government inspectors on a continuous basis, five days a week.

...

My point is, and I think John was in this ballpark, is that thread wires are not the be-all end-all to thread measurement. When you get to extremely high precision thread measurement you use dedicated (and yes, calibrated) gages.

Wires ARE handy to have around if you're not in a production envirnment, and I congradulate Nick on his fantastic purchase. (I would have jumped on them as well if I'd had the chance). But this whole myopic pissing contest just seems really silly.

dp
07-10-2010, 01:24 PM
2. How does buying tools... ANY tools... from a second hand shop help any nation's economy? I've purchased several Starrett mics at auctions, but not one cent of my bid went to Athol, Mass.

Manufacturing the wires creates wealth. The second hand market redistributes that wealth. When money is exchanged, tax revenue is formed. The second hand market also creates opportunity and places quality goods into places where new goods cannot be placed because of economics. This has the potential to create greater efficiency and quality when those second hand markets are also in the manufacturing segment. That creates wealth.

Carld
07-10-2010, 01:37 PM
Robbie, all you need to measure major diameter of an external thread is an outside mic so I feel certain he meant PD, pitch diameter.

Fastners even for the Aero Space people do not have to be a class fit in most cases. I assume they were using die threading heads of some type in the screw machines making the bolts and the dies were checked and changed or adjusted as needed to keep in specs. I doubt the inspection was done with wires but I am sure they used go/no go gages for the bolts and nuts especially for the Aero Space people if required.

The common thread can be cut using a nut that is a tight fit on a tap as a go/no go gage. The only time you need the wires is for a class fit or if your making a thread for something you don't have a test thread to use.

The fact is Nick made a good find and buy and for the stuff he does I am sure he will use them more than the average machinist will. He makes high quality class fit threads and can and will use them.

I too am amazed that this has lasted 16 pages and it is a testament to biased and hard line opinions or slandering and obnoxious behavior. Be that as it may I am sure Nick is rolling his eyes in disbelief at this thread.

MuellerNick
07-10-2010, 01:44 PM
did anyone notice that in the very first post Nick said that the wires were for measuring MAJOR diameter and not PD?

That was my error. Didn't know that you call it pitch diameter. I could have written "Flankendurchmesser" but that would have confused you even more. ;)

Hah! 17 pages! WHAT A GLOAT!

I also bought 6 Flex-Hones. 1€ each. All still shrink wrapped. Is that OK? ;)


Nick

Carld
07-10-2010, 01:52 PM
:D Rolling On The Floor Laughing My Ass Off, says Carl as he chuckles and chortles at Nicks reply.

Mcgyver
07-10-2010, 02:08 PM
2. How does buying tools... ANY tools... from a second hand shop help any nation's economy? I've purchased several Starrett mics at auctions, but not one cent of my bid went to Athol, Mass.


it went in someone's pocket, presumably in your nation. If no one bought them and they ended up in a landfill that hurts the economy - waste is commited and the nations assett account is credited. you could also argue that the purchase indirectly helps Starrett - that the tools have some used value has some affect on peoples willingness to pay their price.

So feel good, you are helping the economy and Starrett

This threads gone all kinds of places other than the OP as threads do, so its not fair to call it a 16 page gloat....I'm happy for ya Nick, but you'll have to do better than thread wires for 16 pages of pure gloat :D

RobbieKnobbie
07-10-2010, 04:03 PM
it went in someone's pocket, presumably in your nation. If no one bought them and they ended up in a landfill that hurts the economy - waste is commited and the nations assett account is credited. you could also argue that the purchase indirectly helps Starrett - that the tools have some used value has some affect on peoples willingness to pay their price.



My goodness. Yes, I understand that the tiny fraction of the original price that someone pays for a second hand tool moves money, generates tax obligations and so forth, but these are in such small proportion to the original purchase that they approach insignifigance...

BUT, having gotten no fewer that TWO economics lessons in retaliation to one generalization does help explain why this thread is now 17 pages long.... and not the least bit less silly than it was six posts ago.


So feel good, you are helping the economy and Starrett


I do, actually. Why else would the old man keep smiling at me like that...

http://www.roseantiquetools.com/sitebuildercontent/sitebuilderpictures/starretthimself.jpg

It's all in good fun, folks. I wasn't pointing out the Major Diameter/Pitch Diameter snafoo in the first post to actually prove the superiority of my urine, it was a sarcastic comment on how anal we can get in some of these threads.



Fastners even for the Aero Space people do not have to be a class fit in most cases. I assume they were using die threading heads of some type in the screw machines making the bolts and the dies were checked and changed or adjusted as needed to keep in specs. I doubt the inspection was done with wires but I am sure they used go/no go gages for the bolts and nuts especially for the Aero Space people if required.


Actually we hadn't used dies or threading heads in years. The majority of the male threads we made were either rolled or turned, sometimes ground. Every threading operations required a variety of gages - occasionally snap gages for major diameter but I don't recall any go/nogo's for male threads. PD's are crucial and the actual values were often required by the customer to be sampled...every tenth or perhaps twentieth PD measurement recorded in the SPC computers, along with a host of other features.

ALL threads we made were to a class fit.

None of which was my point. I'm just saying that while Nick's new wire set is lovely - and I don't wish to detract from his gloat in any way - a set of wires is just not worth seventeen pages of criticism flying every which way. Don't you agree?

dp
07-10-2010, 04:05 PM
I also bought 6 Flex-Hones. 1 each. All still shrink wrapped. Is that OK? ;)


Don't take a picture of them until they're broke in or somebody will claim you never use them!

ulav8r
07-10-2010, 07:09 PM
Worked with 13 centerless grinders for 6 3/4 years. Tolerance on diameters was .0002 at a 1/2" diameter, max roughness of 16 micro inches Ra. Max lobing allowable was .00005 ( 1/2 of a tenth). We had a machine for measuring the lobing that rotated the shaft, probed the OD with an electronically amplified sensor, and printed out a chart that showed the diameter variations. Every shaft made had lobing, even off the brand new grinders after set up by the factory tech.

Another job was in a shop that made watch-like movements that were used in pressure gages that went down-hole in the oil industry. Many of the threads used were non-standard and required the use of thread wires to establish the correct pitch diameter of a male thread that was then used to check the female threads. I you have a call out for a .760 x 24 TPI and only make 10 or less a year, a $450-$600 set of special thread gages with a 6 week leadtime is not reasonable when the part leadtime is two weeks. That is when thread wires is indispensable.

Carld
07-10-2010, 07:10 PM
Absolutely RobbieKnobbie, absolutely.:D

No die heads? Was it on CNC or screw machines? All class fit, that's interesting.

RobbieKnobbie
07-10-2010, 07:40 PM
nope, no die heads what so ever.

Thread turning was done on CNC... lathes and grinders.

Thread rolling was done on manual machines.

I wish I had taken pictures when I was there, some of the operations were pretty specialized and very interesting, but being fresh out of college and only having worked in small machine shops I guess I figured all that stuff was commonplace in big industry!

clutch
07-10-2010, 07:45 PM
Nick,

You are catching way to much crap over this. Maybe you ought to visit us back on RCM again. Kill file the right people and mark ignore threads that will not be on topic and it isn't too bad right now.

Clutch

PeteF
07-10-2010, 08:25 PM
Hey I'm just jealous I don't go to Germany any more or I'd be badgering Nick to show me the bargain shop :p

clutch
07-10-2010, 08:39 PM
Hey I'm just jealous I don't go to Germany any more or I'd be badgering Nick to show me the bargain shop :p

Last time I as there was 1963. How they cried when JFK died, I was a bit too young to understand it all at the time. Our previous support of the Berlin airlift and JFK's play on that seemed to have tugged at their heartstrings.

I was very young then.

Clutch

PeteF
07-10-2010, 08:43 PM
Berlin is a real fun city, especially in Summer. I believe Nick is down south, better skiing down there ... and beer. Oh, and the Bavarians have a good sense of humour, it's just a shame nobody else in the country can understand what they're saying :p

oldtiffie
07-10-2010, 09:12 PM
Nick,

You are catching way to much crap over this. Maybe you ought to visit us back on RCM again. Kill file the right people and mark ignore threads that will not be on topic and it isn't too bad right now.

Clutch

You are quite right Clutch.

For those that have forgotten or chose to ignore the topic and the OP, here it is:


Hi!

Have to tell this:
Was at a second hand tool dealer today. Besides a bunch of this and that and 5 touching prisms (used, they need rescraping) I got a complete box of measuring wires. They are used for measuring the major diameter of threads. AKA "3 wire method".
Saw the box and asked the boss how much. "Umm, don't know. Wait ... no, price is not on the box. 20.- (about $26)". "OK, I take then". Then he asked what it is used for. :D
I really was close to pissing my pants. The set was unused. Price for a single pair is 80.- . The set is complete and has 18 pairs. Makes about 1400.-

Think I can't sleep today because of that deal.

Don't ask for the dealer, I'm in Germany and am not allowed to tell anyhow.

Nick

So the topic/s is/are Nick's' big "win" with his super-accurate 3-wire thread measuring set. I congratulate Nick for his win and for telling us of it.

Following on from that the inferred value of them are the questions of what they are for, how they are used and what levels of accuracy can be reasonably aimed for and achieved in an average HSM shop.

"3-wires" and "3-wire measuring" has been kicked around here on several occasions, both within and this and other threads, but other than talking in related terms, it has not really been addressed in detail for actual use of them.

That is my objective here.

Many or perhaps most assumed that the pitch diameter of the theoretical thread was the one to be measured on a practical thread.

That is not always so as I've shown previously in regard to the limits of the pitch diameters of a common 1/2" - 13 - UNC bolt (male thread) - as posted previously in this thread.

Having got those pitch diameters for that thread, the next thing that needs doing is finding the best wires from the 3-wire set for the pitch of the thread and working out the measurements over those 3 wires for the limits of the thread pitch diameter using the tables provided in/with the 3-wire set.

I have completed the calculations for that, but they need tidying-up after which I will scan and post them for all to see.

Next, I will show how I can do it just about as well (very nearly actually) by just using one wire and the outside diameter of the thread/bolt/male.

Actual measuring with three wires is about as big a PITA and exercise in frustration as there is in the shop. Measuring it may be one thing but measuring it accurately and consistently accurately may be quite another.

I can do it, but don't like it and for obvious reasons would prefer to only use a single (just one) wire instead of three.

I have deliberately NOT "rubbished" Nick or his "find".

But I hope to show that with the wide differences between limits (derived from the tolerance range) that pretty "ordinary" "wires" - or even the shank of a new drill or a bit of O1 or Silver steel or a round precision-ground HSS tool-bit will do very well.

Whether Nick's or other's very accurate 3-wire sets are any better in the HSM shop when using the wide limits on a common thread in an average HSM shop is quite problematical, debatable and possibly unknown.

Mine are item 34302 from CDCO at:
http://www.cdcotools.com

Toolguy
07-10-2010, 10:17 PM
I've done the 3 wire and the 2 triangle with mike and thread mikes, but finally I came up with an easy way to measure threads. The purists on here may have a myocardial infarction, but I will share for those who may be interested. I simply use a caliper to measure across the V of opposite threads and then make the thread I'm turning match the same measurement. On a digital caliper you can even zero the reading on the original and work down to zero on the workpiece.
This works very well because it is only a comparative measurement rather than a calculated one. Also, even though the caliper is angled 1/2 a thread pitch, it still works fine. For finer threads that the outside jaws of the regular caliper don't fit into, I ground down a cheap set on the surface grinder at the tips. For coarse threads like a lathe spindle (8 TPI) I use the wider part of the caliper jaws rather than the tip of the jaws. If you don't have a bolt the right size, measure a thread guage or a tap as the standard to go by. You can tap a hole, then make a bolt a couple thou. under the tap size for a perfect fit. For MuellerNick - Congrats on your good deals! I'm happy for you. Thanks for sharing. Best Regards.

oldtiffie
07-11-2010, 12:42 AM
I've done the 3 wire and the 2 triangle with mike and thread mikes, but finally I came up with an easy way to measure threads. The purists on here may have a myocardial infarction, but I will share for those who may be interested. I simply use a caliper to measure across the V of opposite threads and then make the thread I'm turning match the same measurement. On a digital caliper you can even zero the reading on the original and work down to zero on the workpiece.
This works very well because it is only a comparative measurement rather than a calculated one. Also, even though the caliper is angled 1/2 a thread pitch, it still works fine. For finer threads that the outside jaws of the regular caliper don't fit into, I ground down a cheap set on the surface grinder at the tips. For coarse threads like a lathe spindle (8 TPI) I use the wider part of the caliper jaws rather than the tip of the jaws. If you don't have a bolt the right size, measure a thread guage or a tap as the standard to go by. You can tap a hole, then make a bolt a couple thou. under the tap size for a perfect fit. For MuellerNick - Congrats on your good deals! I'm happy for you. Thanks for sharing. Best Regards.

Toolguy.

The basics are reasonably sound for reproduction of an existing thread.

But a suggestion if I may.

Just use a single "wire" - anything will do - a drill shank, a bit of O1/silver-steel, a bit of round HSS or a bolt shank or a bit of cold-rolled reasonably precision-made or whatever.

Put the "wire" into a thread groove and measure over the outside of the "original/reference thread/bolt/screw" diameter and the "wire". Note the measurement.

Use the same method on the part you are putting a thread on and allow "up" or "down" in size to suit your application.

That too is a "comparator" method that works really well.

It can be used on any thread form or helix angle and there is no need for "3 wires" or any calculations.

All you need is a "master" or "reference" piece.

Toolguy
07-11-2010, 09:31 AM
Thanks Oldtiffie - I like to measure in the Vs because that eliminates the variations of how sharp or flat the crest of the threads are, which can give quite different readings. On your method you are measuring over a V on one side and the crest or top on the other side. Thanks for the post though. Best Regards.

J Tiers
07-11-2010, 10:01 AM
There's more than one type of "thread micrometer".

One has a V point on one side, and a V anvil on the other. They nest at "zero", and give the approximate P.D. Actually known as a "thread micrometer".

The other is just two opposed V points..... they measure the same thing you do, but are not even approximately calibrated... they are basically comparators, and I think their proper name IS "thread comparator mic".

Carld
07-11-2010, 10:02 AM
There are a lot of ways to measure and cut a thread, some good and others not so good. If it seems to work for you do it.

oldtiffie
07-11-2010, 11:42 AM
There's more than one type of "thread micrometer".

One has a V point on one side, and a V anvil on the other. They nest at "zero", and give the approximate P.D. Actually known as a "thread micrometer".

The other is just two opposed V points..... they measure the same thing you do, but are not even approximately calibrated... they are basically comparators, and I think their proper name IS "thread comparator mic".

There are indeed JT.

They are called thread micrometers.

https://www.machineryhouse.com.au/Products?stockCode=Q137

Here is mine with my universal digital micrometer - complete with all anvils:
https://www.machineryhouse.com.au/Products?stockCode=Q129#

They measure the pitch diameter directly - insert the anvils into both the spindle and the anvil, close them together,set micrometer to zero and get measuring. Reads directly to 0.0001" directly with no "3-wires" - or calculations - required. It is the reason why I rarely use my 3-wire set.

At the moment, I only have the 0-25mm (0 - 1") micrometer, but if I buy the 25-50mm (1-2") micrometer I will need the 25mm (1") standard:

https://www.machineryhouse.com.au/Products?stockCode=Q1291

https://www.machineryhouse.com.au/Products?stockCode=Q014

Imperial/inch thread micrometers are available from:
http://www.cdcotools.com/index.php

Index/search for item # 32370 which is 0-1" - cost USD69

RobbieKnobbie
07-11-2010, 01:18 PM
Ironically, I just noticed the following in Paul Holm's article New Life for Old Collets in the December '09 HSM...

Not having a special thread micrometer, I reverted to a version of the three wire method for measuring and sizing threads (photo 3) figure 2 shows how the measurement is made, and how one could calculate the over-the-wire measurementfor a given thread and wire size. In this case, all we are interested in is a comparison of the spindle thread to that of the one being cut. The wire size needed is not a fixed size, but it must be such that it makes contact with the two flat surfaces of the thread profile, somewhere around the midpoint, with the OD of the wires sticking up over the OD of the thread. for my wires, I used three, 2 inch finish nails with the heads cut off...

So I guess you could say 'whatever works for you....'

BobWarfield
07-11-2010, 03:21 PM
There are a lot of ways to measure and cut a thread, some good and others not so good. If it seems to work for you do it.

Here is a nice collection of thread measuring methods along with their pros and cons:

http://www.f-m-s.dk/401b.pdf

Cheers,

BW

J Tiers
07-11-2010, 05:32 PM
Even the best type actual thread mic like Tiffies is only approximate...... factors other than true PD affect it (link notwithstanding), and you can't know which one did, or maybe did not. You really can't know IF any did.

They are improved by standardizing to a known thread gage close to the one to be measured, or to the actual size.

But wires they are not.

John Stevenson
07-11-2010, 05:37 PM
I used three, 2 inch finish nails with the heads cut off...

So I guess you could say 'whatever works for you....'

Lapped of course ?

.

lazlo
07-11-2010, 05:50 PM
I used three, 2 inch finish nails with the heads cut off...

So I guess you could say 'whatever works for you....'

LOL! You would be been better of just sticking it in the nut.

BobWarfield
07-11-2010, 06:18 PM
You would be been better of just sticking it in the nut.

Some on the thread have been trying to make that point in all sorts of ways, LOL!

Best,

BW

speedy
07-11-2010, 06:26 PM
My take on Nicks post is that he was fortunate to come upon quality kit at a good price.
Yeah, sure enough, three pieces of deformed bar, a rough file and a yard rule will do ;) .
Quality kit is what it is....and why not.

Some of you really need to find a hobby:D :D

I'm going outside to watch the frost thaw.

lane
07-11-2010, 07:21 PM
I am glad Nick got a nice set of thread wires . Yes I have a set in a little pack and a few high dollar Van Keuren sets Also 3 set of thread mikes . But most of the time cut and fit is the standard . If the shoe fits wear it.

oldbikerdude37
07-11-2010, 07:27 PM
I do think thread wires are rairly used, I bet more of them have resin from a stoners pluged weed pipe then used to measure threads.

oldtiffie
07-11-2010, 09:19 PM
Even the best type actual thread mic like Tiffies is only approximate...... factors other than true PD affect it (link notwithstanding), and you can't know which one did, or maybe did not. You really can't know IF any did.

They are improved by standardizing to a known thread gage close to the one to be measured, or to the actual size.

But wires they are not.

You are quite right JT.

I discussed "angular and other errors" on several occasions. It takes quite an effort to eliminate all of them - but it can be done. It just takes time and care - and good well set-up cutters/tools.

The "3-wire" formulae and table rely on the thread spiral approximating a groove (nil helix angle) until the helix angle gets to about 5 degrees - which covers most common threads.

Many who get the set-up right set about measuring to or for the nominal pitch diameter - which in most cases is incorrect no matter how well or accurately it is measured or achieved.

The PD's at the thread limits are the ones to aim for. If that is achieved - all other things being correct - the thread will be withing its limits - see Machinery's Handbook.

There was 0.005" between those limits on the 1/2" - 13 - UNC thread that I've used so far previously. With those sorts of limits, the cheap (but quite good) 3-wire sets from CDCO tools are more than good enough for the vast majority of jobs.

The thread micrometer is vastly more accurate and easier to use in the hands of most people, but never the less, the PD's need to be worked out for the limits to work between on that thread micrometer as well.

Your comment:

Even the best type actual thread mic like Tiffies is only approximate...... factors other than true PD affect it (link notwithstanding), and you can't know which one did, or maybe did not. You really can't know IF any did.
can be expanded to read or mean that the finished thread will "fit where it touches" its mating part/s unless all those possible errors and variables are eliminated or reduced to an acceptable minimum.

I agree with that.

J Tiers
07-11-2010, 09:36 PM
I was thinking more about faults with the thread cutting..... a burr thrown up on the major diameter, for instance, which can cause a problem with the thread mic, which rests against the whole thread form, but NOT so much with the wires, which the burr may not affect (depends how big the burr is, obviously). The wires will sit at or near the PD, and the burr may not reach above them.

I've got wires, thread mics, triangles, and so far the wires seem to give the best results, despite the hassles.

Mics are a little easier to use, but you need a bunch of them, or one expensive mic with a lot of fiddly bits.

Triangles have all the problems of mics, and are harder to hold.

I like the mics. You can always increase your fussiness to fit the job with the mics. And you don't need tables.

oldtiffie
07-11-2010, 10:15 PM
You are still very much "right on the money " JT.

So far we seem to be considering making a thread from "tables" - which in itself is quite OK.

The limit DP's can be got directly from Machinery's Handbook and used directly with a thread micrometer without any calculations at all.

But its vastly easier to make a thread very near to size if you are duplicating a thread that already exists.

For example, if I needed to make the 1/2" -13 - UNC 2A bolt referred to earlier (2A/2B combination is the usual "fit") I get a good quality rolled high strength (structural) bolt or a hex-headed socket screw as they are generally very good as regards size and profile.

I'd use a single "wire" that contacted the flat parts of thread sides/flanks so that the "wire" protruded above the bolt diameter and then measure over both the bolt and the "wire". That is the dimension I would be after when I cut the thread using that same "wire".

If I was within +/- 0.002" I'd be pretty right for most work.

The "new" OD needs to be pretty close to the "sample" thread - but any "errors" are easy to allow for.

I have in effect used the sample thread and the wire to make a new thread by "comparison" rather than by calculation or need of "3 wires" - and it works a treat!!!

I have no need to calculate "in-feed" or anything else. Just work to that size.

It works equally well whether using the "plunge right in" or the "off-set the compound/top slide by 29.5 degrees" or other methods as well.

It also works very well for acme threads when duplicating an existing thread - a cross-slide screw for example. Just find a part of the thread that is not worn, put a "wire" in the thread, put a micrometer over the "wire" and the lead-screw and you will have your dimension to work to to cut the acme thread using that same "wire".

If the new thread measurement over the wire and the thread OD is correct as compared to the sample, the new thread "compares" very well.

This is all pretty basic "Machine Shop Applied Maths 101" really.

MuellerNick
07-12-2010, 02:24 AM
You can argue ad infinitum, the fact that I got exactly this set for that price is a huge improvement for me.

Options:
a) Buy a new thread micrometer. I was in that, but it also requires buying the inserts for the different pitches. -> vacuum in the wallet
b) Use paper clips or other precision lapped wires is a handling pain. Been there, done that.
c) buy gages and never have the one needed at hand

Exactly that set I got for little money solved all my needs:
* precise
* cheap, but no crap at all.
* almost as easy to handle as a thread mike. I just have to add an offset value
* works for metric threads and 55-inch-crap
* extremely flexible, also good for poly-V belt pulleys, trapezoidal threads etc.


So you can continue to discuss how overengineered my set is, that it is too precise, that you personally never used one and thus it is crap, that the plain wires without that holder are a pain to use, that needles are as good as long as you find them in the right diameter, that you never had to make a precise thread, that you always were able to have access to the mating thread, $whatever


Nick

Black_Moons
07-12-2010, 02:36 AM
MuellerNick: Best thread wires ever.

Random story to make this post longer: I like the time I made my threads too big.
I measured the crests OD perfictly.. I measured the pitch diamiter based on an aluminum test part that fit perfictly.. I turned the steel replica of that aluminum part perfictly.. Hey.. this.. is.. a..really.. tight fit... Hmmmm

Problem? I did'nt use a toping style threading insert. My crests where square.
The aluminum test part deformed into round crests easily enough the first time it was screwed in. The steel.. Not so much. Though it did eventualy with enough torque :) Now I have a thread with 0 clearance as it was actualy rolled by the mating thread.

Your tools are only as good as the loose nut behind the wheel.

RobbieKnobbie
07-12-2010, 04:12 AM
... Now I have a thread with 0 clearance as it was actualy rolled by the mating thread.


Hey, isn't that sort of the idea behind NPTF threads? You may be on to something there... a self sealing straight thread:D

(now if only we had a way of measuring the PD...)

oldtiffie
07-12-2010, 05:18 AM
You can argue ad infinitum, the fact that I got exactly this set for that price is a huge improvement for me.

Options:
a) Buy a new thread micrometer. I was in that, but it also requires buying the inserts for the different pitches. -> vacuum in the wallet
b) Use paper clips or other precision lapped wires is a handling pain. Been there, done that.
c) buy gages and never have the one needed at hand

Exactly that set I got for little money solved all my needs:
* precise
* cheap, but no crap at all.
* almost as easy to handle as a thread mike. I just have to add an offset value
* works for metric threads and 55-inch-crap
* extremely flexible, also good for poly-V belt pulleys, trapezoidal threads etc.


So you can continue to discuss how overengineered my set is, that it is too precise, that you personally never used one and thus it is crap, that the plain wires without that holder are a pain to use, that needles are as good as long as you find them in the right diameter, that you never had to make a precise thread, that you always were able to have access to the mating thread, $whatever

Nick

Nick,

if you feel aggrieved - so be it.

I have not only not demeaned you or your 3-wire set purchase but I have gone to some pains to say just that - several times in the course of this thread.

To that end I do not owe you an apology.

If for what-ever reason you have mis-interpreted what I've said, that's your problem and not mine, in which case I not only don't owe you an apology, but I won't be giving you one either.

It is your absolute right to buy what ever tools etc. that you choose to and to use them as you wish.

That said, others have the same rights as you do and are to be respected whether they agree with how you see or do things or not.

Everybody and everybody here can work to what ever standards he wishes - its his choice.

One of the big problems with any set of 3-wires - yours and my Chinese ones included - is that there is a lot of maths that are easy to get wrong, even by those who have the required maths ability, and well beyond many of a lesser ability with maths.

I will go through the maths shortly - using the "3-wires" and then just one wire.

Thread micrometers and the "one wire comparative" method discussed recently have already been explained - as they should have been - to facilitate and provide all or most options for measuring external "V" screw threads within the needs and ability of each reader and for them to choose for themselves.

To that end I am not going to either restrict the discussion to just the "3-wires" method on the one hand nor am I going to have - or be a party to having - it rammed down the throats of others as the "one and only true way" to the exclusion of any or all other practical means and methods.

oldtiffie
07-12-2010, 06:24 AM
Here are the maths for using a micrometer to measure over 3 precision wires to measure the diameter of the pitch cylinder - aka pitch diameter aka PD - of the 1/2" - 13 - UNC 2A external thread as discussed and posted previously.

Just to re-cap:

The thread is the standard 60* UNC/ISO/DIN is the standard UNC thread form the details of which are at:
http://i200.photobucket.com/albums/aa294/oldtiffie/Screw_threads/Screw_threads2.jpg

Here is the 1/2"- 13 - UNC - 2A external thread (bolt/screw) under discussion and for which the various (3) measurements on the micrometer are required for the (3) PD's will be worked out:
http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book_Fasten_P72-73_1.jpg

Here are the values and formulae to be used and the tables for the 55* (BSW) and 60* (UNC/ISO/DIN) screw thread pitches.
http://i200.photobucket.com/albums/aa294/oldtiffie/Screw_threads/3-wire3.jpg

The thread is 13 tpi so I have used the 0.0450" diameter wires (3) the "constant" for which is 0.6838.

Here are the maths in which I have solved for:

- the measurements over the wires for:
A. ----- the standard/nominal PD (0.4500");
B. ----- the upper limit PD (0.4485");
C. ----- the lower limit PD (0.4435); and
D. ----- the difference between B and C (aka the "working range" on the lathe).

http://i200.photobucket.com/albums/aa294/oldtiffie/Sketches/3-wirecomps1.jpg

Next, I will do the measurement over one wire using the figures above as its much easier using one wire than it is using three wires and with care will be just about as accurate and certainly within the 0.005" "working range" for this particular 1/2" - 13 - UNC - 2A external thread.

MuellerNick
07-12-2010, 06:34 AM
One of the big problems with any set of 3-wires - yours and my Chinese ones included - is that there is a lot of maths that are easy to get wrong, even by those who have the required maths ability, and well beyond many of a lesser ability with maths.


Oh yea! VERRRRY complicated, indeed.
Maybe so complicated because you announced the formula over 3 days or so.

But then, you already posted a table for the offsets (within limited helix angels).

The formulae are here: http://www.emte.ch/S-Produkte%2005.asp
And if you are mathematically challenged, just type in the numbers into the boxes of that and press the magic <enter>key.
And when I'm in the mood (or mode :D ), I'll program an app for my iPad, so I have it right where I work.

You seem to chew things until boredom quite frequently.


Nick

oldtiffie
07-12-2010, 06:41 AM
Nick.

I am sure you don't need me to approve your indulging yourself as you choose.

But for what its worth - please continue.

Its nice to see a man happy in his work.

John Stevenson
07-12-2010, 07:38 AM
Oh yea! VERRRRY complicated, indeed.
Maybe so complicated because you announced the formula over 3 days or so.



You seem to chew things until boredom quite frequently.


Nick

Perhaps it's because he can't find a Tiffiepedia link ? :confused:

Or, saints preserve us, he's never used the set he has. ? :confused:

.

J Tiers
07-12-2010, 08:34 AM
Dunno, Tiffie.... the one wire method may not be worth the candle.

I know that one wire, with perfect threads, will "work"........

But as I think you may have mentioned, you are still "at the mercy of" the thread major diameter...... And THAT may be in error.....

The PD can be perfect, and there may be an over-sized flat at the major diameter. or a full-V thread, or a burr, etc. Then you will measure the thread as wrong, when it is perfect in pitch diameter (the other errors notwithstanding).

This is much like measuring the diameter of a cylinder, with the 'turning fuzz" still on it. You measure it as large, and you "fix" that, only to find out that now it is really UNDER-sized.

I will "give you" the methods of "try the nut", "dial the depth of thread", "single wire method", "measure OD and hope", etc. But they are all depending on factors other than the actual pitch diameter.

All very useful when precision is un-necessary, or you simply have no other option available, of course.

But if you need any accuracy, and are going to go to the trouble to calculate the readings for one wire, you might as well cut that wire in 3 pieces and measure the regular way!

oldtiffie
07-12-2010, 10:43 PM
Dunno, Tiffie.... the one wire method may not be worth the candle.

I know that one wire, with perfect threads, will "work"........

But as I think you may have mentioned, you are still "at the mercy of" the thread major diameter...... And THAT may be in error.....

The PD can be perfect, and there may be an over-sized flat at the major diameter. or a full-V thread, or a burr, etc. Then you will measure the thread as wrong, when it is perfect in pitch diameter (the other errors notwithstanding).

This is much like measuring the diameter of a cylinder, with the 'turning fuzz" still on it. You measure it as large, and you "fix" that, only to find out that now it is really UNDER-sized.

I will "give you" the methods of "try the nut", "dial the depth of thread", "single wire method", "measure OD and hope", etc. But they are all depending on factors other than the actual pitch diameter.

All very useful when precision is un-necessary, or you simply have no other option available, of course.

But if you need any accuracy, and are going to go to the trouble to calculate the readings for one wire, you might as well cut that wire in 3 pieces and measure the regular way!

Just about everything in the shop relies on the competence and intelligence of the machinist/operator. Without that, all else is at best questionable and likely to be somewhere between a less than satisfactory job - or a failure.

I have addressed the requirements and issues as regards machine and tool use and set-up on several previous posts here.


But as I think you may have mentioned, you are still "at the mercy of" the thread major diameter...... And THAT may be in error.....

I will deal with that issue in detail, in a future post here. It should sort that out.

You may be quite surprised at how accurate the "one wire" method can be - but it requires the calculation of the "3 wires" for the limits of the pitch diameters as in a previous post here.

I will sort that issue out as well.

What is at issue here is that there is a lot more latitude allowed than many realise when making standard threads, but people seem to want or see or need to work in "tenths" when working in "thous" may be quite adequate.

All of the required information as regards limits etc. is in Machinery's Handbook but people seem use the common drilling and tapping tables instead.

The tables with all "3-wire" sets, no matter which manufacturer or what-ever the country of origin, will all use the same equations/formulae and include a note to the effect to use Machinery's Handbook or similar. Its mentioned twice in this pic (even if the spelling is poor):
http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/3-wire3.jpg

dp
07-12-2010, 11:55 PM
Single wire method:

* Measure the wire
* Measure the thread, no wire
* Measure the thread with one wire
* Add twice the difference between no wire and one wire to the no wire value
* Do the math or look up in a table for you wire size and pitch

oldtiffie
07-12-2010, 11:59 PM
Close Dennis - very close.

There are actually two "one wire" solutions.

Later/soon.

oldtiffie
07-14-2010, 07:28 AM
I said previously that I'd get back to show that measuring with 1 wire can be just about as accurate as measuring with 3 wires.

Please review this sheet to bring yourself up to date:

http://i200.photobucket.com/albums/aa294/oldtiffie/Sketches/3-wirecomps1.jpg

OK - now into it with this sheet:

http://i200.photobucket.com/albums/aa294/oldtiffie/Sketches/3-wirecomps2.jpg

The 3-wire standard measurement is on the left. The micrometer measurement consists of the bolt diameter plus two gaps between the micrometer and the bolt outside diameter.

The 1-wire measurement is on the left.The micrometer measurement consists of the bolt diameter plus only one of the two gaps in the 3-wire method and only requires 1 wire instead of 3.

In both cases, the 3-wire measurement needs to be calculated - as previously.

With the 1 wire method the outside diameter of the bolt needs to be measured accurately and for a 1/2" - 13 - UNC - 2A bolt is required to be between the limits of 0.4985" and 0.4876" (a difference of 0.0124" - your "working limits" for turning the bolt) - as per Machinery's Handbook 27 page 1900.

I have arbitrarily chosen a bolt diameter of 0.4900" as an example only.

This pretty well finishes the "3-wire" discussion per se but I will continue with further discussion on other methods and sources.

Using a single wire is vastly easier than using three wires and because of that is arguably at least as accurate.

I will take any queries or suggestions if they are required.

Later.

JCHannum
07-14-2010, 08:35 AM
Using a single wire is vastly easier than using three wires and because of that is arguably at least as accurate.

Then since using no wires is even easier, is it also arguably at least as accurate?

J Tiers
07-14-2010, 08:45 AM
If I understand your argument, it is that because of the "limits", you can get within those limits either way, and errors from burrs may not be important.

Possibly so.

if you measure your OD first, you can maybe tell if you are in a position to measure PD your way. If the OD is within limits.

It's a worthwhile thing to know how to do. It probably does not have the accuracy to be "worth the candle" unless you are forced by circumstances to use it.

My argument is simple......

You are measuring PD. OD is a separate issue, or should be, coming under the heading of "thread form".

Wires measure this "directly", they contact the PD (ideally) or come very close, and the constant is just that. an adder due to the form of the contact device.

measuring with ANY method which depends on the actual OD also depends on:

a) The OD being concentric with the PD

b) The OD being actually the OD of a correct thread form.


With the typical cut thread, neither one is certain.

Burrs may be uneven and cause the measured OD to be non-concentric.

Burrs may cause the OD differ from the true.

Burrs are quite likely from the thread-making process. (Cutting makes much larger burrs than grinding).

And, burrs may cause the operator tpo continue until the thread is already undersize, due to errors in measuring the true OD resulting from them.

So the one-wire method may , and probably will, have an error of unknown amount vs true pitch diameter, due to not directly depending on PD.

The error of wires may be known, by measuring the wires, and by knowing the form of the cutter. Burrs occur, but are outside the measuring area.


Burrs can drastically affect the measurment with the one-wire method.

Of course tehy also can drastically affect the measurement with thread mics.

Burrs, unless catastrophic, will not affect wires (plural) or triangles. And such "catastrophic" burrs would also affect the one wire method at least as much.

If you are going to go to the trouble, 70% of it, you may as well go all teh way and use 3 wires.

Or bag it and get a set of triangles, or use thread mics

MuellerNick
07-14-2010, 09:39 AM
a) The OD being concentric with the PD

That's where the 1-wire method fails completely.


Nick

dp
07-14-2010, 10:47 AM
That's where the 1-wire method fails completely.


Nick

It can be easily tested with a one, two, or three wire method, so unless the person testing the thread is a smoldering idiot unlikely turn a proper thread let alone one to bother measuring threads at all, this concentricity issue is only a possibility, not a certainty.

MuellerNick
07-14-2010, 12:43 PM
this concentricity issue is only a possibility, not a certainty.

It simply depends on how the thread was made.
But then, you can use that method to check concentricity.


Nick

strokersix
07-14-2010, 12:57 PM
Yes but: Error caused by wires of questionable accuracy ought to be less if there is only one wire involved instead of three!

:)

MuellerNick
07-14-2010, 01:09 PM
But you introduce a new error source: Measuring the OD.


Nick

strokersix
07-14-2010, 01:10 PM
I know that. I was just bringing the argument back around where it started.

oldtiffie
07-14-2010, 10:08 PM
I sense a fair bit of "sour grapes" here as a few machining urban myths are exposed and blown out of the water.

There is rarely any need for super accuracy in every-day screw-threads and threading. There is a lot of lee-way and tolerance allowed with very ample space between machining limits in most cases of metric (ISO/DIN) and imperial/inch (UNC/UNF SAE etc) at most stages and still be within the standard limits and tolerances for "class of fit" at the end of what is a pretty simple process.

If some see a need to use super-accurate 3-wire sets and/or work to microns or millionths of and inch - so be it - so long as they are within the standard tolerance and limit zones. But for the general case it is neither needed nor required and is a waste of time and effort.

But for 99% of most shop work, Machinery's Hand-book, a reasonable 3-wire set (the Chinese sets are more than adequate) and a common desk-top ("school") calculator and you have all that you need.

In the vast majority of cases, older American and later Chinese machines, tools and "3-wire" sets are quite adequate.

I will cover the relevant sections of Machinery's Handbook later. But suffice to say that if standard "3-wire" sets are used for standard threads, the "over the wires" measurements for the limits of each pitch diameter will be right there - ready to use - no calculations required - just take it off the tables.

I see that some of the usual suspects, "knockers" and "nay-sayers" are at it again and while they espouse the need for "microns" etc. they seem to have considerable concerns regarding getting a decent finish on the outside diameter and/or being able to measure it accurately enough and having it accurately concentric enough with the lathe head-stock spindle etc.

I suspect that some may be concerned or resent some of the "secrets" of 3-wire measurement and screw-cutting being exposed for the relatively simple matter that it really is.

Just for the record - again - there is an awful lot of bull-$hit about the need for "microns" and "millionths of an inch". It is near enough to say that:

- 1 micron ~ 40 millionths of an inch.

- 0.01mm = 10 microns ~ 0.0004" (4 "tenths").

- 0.001" ~ 0.025mm ~ 25 microns

So let's not get too carried away with the quite unjustified "need" for and the associated "WOW factor" and "bragging rights" of quoting those all too often unjustified small amounts that are represented by too many insignificant figures to the right of a decimal point.

All of the newer machinists here may rest assured that they can make a very good and accurate thread with the minimum of fuss and tools in the minimum of time.

Those with a reasonable - say High School - level of maths and logic will find a lot of the mystery swept way - as it should be.

I will address the relevant sections of MHB later.

I will discuss the various methods that I have covered thus far as well.

If I have time, I will discuss a quite accurate way of measuring internal threads and if necessary making your own quite accurate external "thread guage" that will all be quite accurate enough for most work in the HSM shop.

Later.

J Tiers
07-14-2010, 10:26 PM
Bu**er t' microns......

You can be off by several thou due to concentricity errors and burrs.....

To repeat.......

1) there is no need for ANY wires for most work, let alone a one-wire method. Sufficient accuracy can be had with the mating nut, or whatever.

2) If you really NEED accuracy, why bother with an "iffy" and doubtful one-wire method?

You have to go to the tables for the 3 wire correction anyway, and then do a bit of math.

And after you have done all that to avoid holding 2 more wires, you don't know the PD anyway....... you have a "pretty good guess" at it, the goodness of which is determined by "unrelated" parts of the threaded part.... thread crests, burrs, concentricity, etc)

Triangles, or a set of 'chinese chopsticks" will get enough accuracy to do most anyone's work that can be done on the average 40 to 70 year old Atlas or other "cheaply made to a price, but kinda OK" lathe. That goes for the "chinese winches" also.

The basic accuracy and repeatability of your measurement techniques, instruments, and temperature control is going to come into question for any better work requiring the super-good wires. (but if you can get them for a song, there is nothing WRONG with them, of course)

If you Gotta have the microns, you know it already, and have probably solved your problem without our input.

S_J_H
07-14-2010, 11:18 PM
1) there is no need for ANY wires for most work, let alone a one-wire method. Sufficient accuracy can be had with the mating nut, or whatever.


Agreed.

As a HSM machinist when I first began to use a lathe and mill I would take forever to make anything. I would measure, remeasure and get all hung up on everything being dead nuts.
It did help to teach me proper methods and learn to make precise fitting parts.
I now do not waste my time being super anal on parts that do not need that kind of attention to detail and now I get a hell of a lot more done in the same amount of time.

I have never had any trouble thread cutting. IMHO it's a easy and simple machining op.
I do think it's cool the OP got a nice set of super accurate wires, as having more tools is always a good thing.:D
Steve

RobbieKnobbie
07-14-2010, 11:41 PM
... it is neither needed nor required and is a waste of time and effort...

Wow, Tiffie, you about summed it up in one line there.

oldtiffie
07-15-2010, 02:24 AM
Originally Posted by oldtiffie
... it is neither needed nor required and is a waste of time and effort...


Wow, Tiffie, you about summed it up in one line there.


Thanks RK.

I said what I meant and meant what I said - still do.

Lets go back to our friend the 1/2" - 13 - UNC - 2A bolt.

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book_Fasten_P72-73_1.jpg

If the "nut" pitch diameter was say about mid tolerance at say 0.4530" and you made the bolt "pretty neat" at say a "thou" (0.0010") "under" at say 0.4520" you would not only be way out of the bolt tolerance zone (0.4485"/0.4435") but you would not even be out of the "nut" zone (0.4565/0.4500").

In any case, it seems that the "nut" was never checked for size or limits either.

There is a whole litany of "sins" here by a lot who seem to profess to "always doing it right" and "rubbishing" those of us in the "make 'er fit Brigade" etc.

So much for "working to standards".

speedy
07-15-2010, 02:44 AM
I will never interchange UNC with BSW again....or maybe I will.

oldtiffie
07-15-2010, 03:31 AM
I will never interchange UNC with BSW again....or maybe I will.

Nah.



....UNC......vs.....BSW

1/4" - 20 vs 1/4" - 20

5/16" - 18 vs 5/16" - 18

3/8" - 16 vs 3/8" - 16

7/16" - 14 vs 7/16" - 14

1/2" - 13 vs 1/2" - 12

9/16" - 12 vs 9/16" - 12

5/8" - 11 vs 5/8" - 11

3/4" - 10 vs 3/4" - 10

7/8" - 9 vs 7/8" - 9

1" - 8 vs 1" - 8

You know as well as I do Ken that will never change as its far too handy - other than the Yanks 1/2" - 13 - UNC and the 1/2" - 12 BSW.

They will go together pretty well most times and need a bit a "nudge" or "help" along the way in others.

We have plentiful supplies of the comon non- HT as well as structural grades in both UNC and BSW here.

It works - sort of - mostly.

It must be different down here south of the Equator.

I sure am glad about that!!

speedy
07-15-2010, 05:52 AM
Yep, 1/2" is the one to avoid but at a pinch and if you only require a few threads it will do...just to the point of stripping:D

oldtiffie
07-15-2010, 06:42 AM
............................

lazlo
07-15-2010, 12:11 PM
(the Chinese sets are more than adequate

How do you know? Break open your CDCO package, and measure the wires for roundness, straightness and size, and the delta between each 3-wire set and let us know.

According to Machinery's Handbook:


"A set of three measuring wires should have the same diameter within 0.0002 inch.

To measure the pitch diameter of a screw-thread gage to an accuracy of 0.0001 inch by means of wires, it it necessary to know the wire diameters to 0.00002 inch." [That's not a typo -- the thread wires must be on-size to 2 hundred-thousandths of an inch to measure a tenth in Pitch Diameter].

"If the diameter of the wires are only known to an accuracy of 0.0001 inch, an accuracy better than 0.0003 inch in the measurement of the pitch diameter cannot be expected."

Darn, that leaves out the finishing nails :rolleyes:

Harbor Freight sells those $6 thread wire kits -- surely the same stuff that CDCO, Shars, and Arc-Euro are selling. I'll pick up a set with my 20% coupon :p and see how they measure.

lazlo
07-15-2010, 12:18 PM
1) there is no need for ANY wires for most work, let alone a one-wire method. Sufficient accuracy can be had with the mating nut, or whatever.

2) If you really NEED accuracy, why bother with an "iffy" and doubtful one-wire method?

Exactly. As has been said several times in the thread, thread wires are meant for measuring gauges. If you're just cutting a single nut/screw pair, just thread the damn nut on.

Like Bob W. and his AA-class plug gauges, I bought an immaculate set of Van Keuren thread wires from one of the regulars on PracticalMachinist for $30. I've used them once or twice in the last three years, but for 99% of my work I use a nice, old Mitutotyo thread mike.

All this angst to convince Nick that he doesn't need thread wires, and that Chinese thread wires are just as good... :rolleyes:

dp
07-15-2010, 12:32 PM
How do you know? Break open your CDCO package, and measure the wires for roundness, straightness and size, and the delta between each 3-wire set and let us know.

Any wire will work. Any two wires will work. Any three wires will also work. All that is needed is to know the diameter, and that the diameter is practical for the purpose. It is convenient if they are all the same size but it won't be a show stopper if they are not. It is convenient if they are the sizes used from already tabled data, but it won't be a show stopper if they are not. It is convenient if they can be used interchangeably by all employees but if you are the only one using them, it is not a show stopper that you must create your own tables.

This silly and simple process has become way over blown.

dp
07-15-2010, 12:33 PM
All this angst to convince Nick that he doesn't need thread wires, and that Chinese thread wires are just as good... :rolleyes:

I haven't seen much angst regarding Nick's need for precision thread wires but I have seen a lot of justification why others do not.

lazlo
07-15-2010, 12:44 PM
Any wire will work.

No, it won't. As has been said a dozen times, the wire must be round, straight, and of a known size. A finishing nail, a piece of music wire, or a CDCO thread wire, is going to be none of the above.

More importantly, there's an optimal size for the thread wire too - you need to pick the thread wire that contact the thread at the pitch line (mid-slope) of the thread so it's least affected by errors in the thread angle.


This silly and simple process has become way over blown.

The only people crapping on Nick's thread are the one's who bought Chinese thread wires :)

lazlo
07-15-2010, 12:49 PM
I haven't seen much angst regarding Nick's need for precision thread wires

I've got Tiff on ignore, so I only see the posts that other's have quoted, but there are many quotes like this in this thread:


... it is neither needed nor required and is a waste of time and effort...

The same characters that were attacking the usefulness of Co-axial Indicators, 3D-Tasters, real Kurt Vises, ...

John Stevenson
07-15-2010, 02:01 PM
The only people crapping on Nick's thread are the one's who bought Chinese thread wires :)

Hey I didn't buy them, I was given them. :D

I bought the Starrett ones although I must admit other then one try just see see how they worked I have never used them in anger.

My Chinese ones look like Tiffies - unused.:rolleyes:

dp
07-15-2010, 03:15 PM
I've got Tiff on ignore, so I only see the posts that other's have quoted, but there are many quotes like this in this thread:


Originally Posted by oldtiffie
... it is neither needed nor required and is a waste of time and effort...


The same characters that were attacking the usefulness of Co-axial Indicators, 3D-Tasters, real Kurt Vises, ...

But what he said is true in the full context. And I don't see that it was aimed at Nick as you suggested.

dp
07-15-2010, 03:22 PM
No, it won't. As has been said a dozen times, the wire must be round, straight, and of a known size. A finishing nail, a piece of music wire, or a CDCO thread wire, is going to be none of the above.

You left out the complete quote which I'll repeat here.

Any wire will work. Any two wires will work. Any three wires will also work. All that is needed is to know the diameter, and that the diameter is practical for the purpose.



More importantly, there's an optimal size for the thread wire too - you need to pick the thread wire that contact the thread at the pitch line (mid-slope) of the thread so it's least affected by errors in the thread angle.

This matters only if you wish/need to use existing tables. If you create your own tables the wire diameter need only ensure the wire contacts the thread faces, and that the wire diameter ensures the wire protrudes beyond the major diameter so the micrometer can contact it.

The wire quality (roundness, straightness) minimizes the error range of the repeated measurements. Do you know what the range of error might be if a wire is off by +- 0.00001"

John Stevenson
07-15-2010, 04:00 PM
Do you know what the range of error might be if a wire is off by +- 0.00001"


[1] More to the point can you even measure it to ANY degree of accuracy.

[2] does it actually matter given you are threading on some clapped out, year dot, ex industrial machine that was made on machinery not even capable of half a thou anyway.

[3] Don't forget the curvature of the earth.

.

lazlo
07-15-2010, 05:10 PM
The wire quality (roundness, straightness) minimizes the error range of the repeated measurements. Do you know what the range of error might be if a wire is off by +- 0.00001"

I think you meant a tenth, not a hundred-thousanth, but yes, actually I do know the error range, because I posted it in the post you're replying to ;)


"If the diameter of the wires are only known to an accuracy of 0.0001 inch, an accuracy better than 0.0003 inch in the measurement of the pitch diameter cannot be expected."

So there's ~ 3x error magnification between variation in the wire diameter and the measured thread error. Add taper and out of round to that, and you see pretty quickly why thread wires are ground, lapped and polished.

To put it in perspective, here's the tolerance for piano wire (very likely what the Chinese Thread Wires are):


"Piano Wire(Steel);Size:1.6mm diameter; Tolerance:+/-1.015mm"

So that's an allowable diameter variation of 40 thou for a nominal wire size of 0.0623" - a 50% error margin :cool:
I picked 1.6mm because .0625" is the optimal thread wire size for 16 TPI.

Using Machinery's Handbook's guidance that the measured thread error is 3x the diameter variation, you get a measurement error of 3 x .040 = 0.12" Nice!



there's an optimal size for the thread wire too - you need to pick the thread wire that contact the thread at the pitch line (mid-slope) of the thread so it's least affected by errors in the thread angle.

This matters only if you wish/need to use existing tables. If you create your own tables the wire diameter need only ensure the wire contacts the thread faces, and that the wire diameter ensures the wire protrudes beyond the major diameter so the micrometer can contact it.

You're missing the point Dennis. The optimal measuring point is halfway down the thread flank. You want a wire that contacts at the thread's pitchline because that's where the measurement is least affected by errors in the helical angle.

So Machinery's Handbook has a formula to calculate the optimal thread wire diameter for a given thread:


"The following formula for determining the 'best-size' wire: the diameter for pitch-line contact, A = one-half the included angle of thread in the axial plane.


Best-size Wire = 0.5 pitch
Cos A


So I agree, thread wires are for counting angels, but don't kid yourself that $6 thread wires are anywhere close to what Nick scored, anymore than a Chinese gage block is anywhere close to a Mitutoyo, or Starrett gauge block. Yes, they're both rectangle and shiny, but...

dp
07-15-2010, 09:09 PM
I

"Piano Wire(Steel);Size:1.6mm diameter; Tolerance:+/-1.015mm"

So that's an allowable diameter variation of 40 thou for a nominal wire size of 0.0623" - a 50% error margin :cool:
I picked 1.6mm because .0625" is the optimal thread wire size for 16 TPI.

No where has it been suggested to not know the diameter of your wires. It doesn't matter what the tolerance is if you know that dimension. I stated that but you're not getting it. I also stated the diameter has to be appropriate for your thread. It can't be too big, can't be too small. But it also doesn't have to be just right unless you intend to use tables published for wires of a specific diameter.

If you know the diameter of your wire, the pitch of your thread, and the PD of your screw you can calculate the error of your screw based on the wire-wire dimension. If it is something you will do a lot with that set of wires, it would be a good idea to table the data so you can be more efficient.

lazlo
07-15-2010, 09:15 PM
If you know the diameter of your wire,

You know the diameter at which point? Piano wire, or any drawn wire for that matter (or a nail :rolleyes: ) isn't straight or round either.

That's why thread wires have NIST standards for roundness and taper, as well as nominal size. Those standards from Van Keuren that I posted earlier weren't abitrary -- it's the straightness/roundness/diameter spec to meet the NIST standards.

So picture this scenario: you have three finishing nails that vary in diameter by 50 thou (and that's being very kind). They're mishapen from the drawing and heading operation, and they're not remotely straight. You lay these three nails in your thread grooves, and use a *cough* micrometer to measure the distance between the top two nails, and the bottom nail. That tells you basically, nothing.

You might as well just stick the thread in the nut.

oldtiffie
07-15-2010, 10:19 PM
Originally Posted by dp
Do you know what the range of error might be if a wire is off by +- 0.00001"

[1] More to the point can you even measure it to ANY degree of accuracy.

[2] does it actually matter given you are threading on some clapped out, year dot, ex industrial machine that was made on machinery not even capable of half a thou anyway.

[3] Don't forget the curvature of the earth.

.
John's post is dead right - this time as well as previously. But some seem to have ignored it - which they should not.

Using 3-wires is at best difficult to do and even more difficult to do accurately and repeatedly so "tenths" at most becomes irrelevant in that regard at least. Even the lead of new lead-screws are not all that accurate really - "tool room" and even some of the better ground ball-screws included - so they would need to be very accurately "error-mapped" and compensated for to even think about being certain of getting the thread pitch/lead consistency that is inferred in having to use 3-wires to a "tenth" or so.

This post by Lazlo is pretty well correct theoretically but is way off the mark as regards working for the normal 1A, 2A, 3A external threads where the range of limits for the pitch diameter is so wide (in excess of 0.005"):


I think you meant a tenth, not a hundred-thousanth, but yes, actually I do know the error range, because I posted it in the post you're replying to


"If the diameter of the wires are only known to an accuracy of 0.0001 inch, an accuracy better than 0.0003 inch in the measurement of the pitch diameter cannot be expected."
So there's ~ 3x error magnification between variation in the wire diameter and the measured thread error. Add taper and out of round to that, and you see pretty quickly why thread wires are ground, lapped and polished.


This one is wrong as well:
You're missing the point Dennis. The optimal measuring point is halfway down the thread flank. You want a wire that contacts at the thread's pitchline because that's where the measurement is least affected by errors in the helical angle.

So Machinery's Handbook has a formula to calculate the optimal thread wire diameter for a given thread:


"The following formula for determining the 'best-size' wire: the diameter for pitch-line contact, A = one-half the included angle of thread in the axial plane.

Code:
Best-size Wire = 0.5 pitch/Cos A

All thread measuring processes: 3-wire, 1-wire, thread micrometers etc. - all presume and assume that the the thread angle (60* or 55* mostly) are precisely on size, their sides/flanks straight and their axis of symmetry at 90* to the thread/head-stock axis.

It does not matter if the wire/s do not contact the thread flanks/sides at the nominal or any other pitch diameter as by using the "best wire" for the required thread tpi or lead as well as the "constant" (from the 3-wire table) any deviation from the pitch diameter is compensated for.

http://i200.photobucket.com/albums/aa294/oldtiffie/measuring/3-wire3.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Black_book/Black_book_Fasten_P72-73_1.jpg

I think that Lazlo is referring to measuring the nominal pitch diameter - which is a big mistake.

Have a(nother?) look at the thread classifications, intended usage and limits for each of the Classes 1A, 2A and 3A external threads.

With the single exception of the rarely used or needed Class 3A external thread the nominal pitch diameter is outside the tolerance range and even for the Class 3A the limits are:
- upper limit = 0.4500" (right on the nominal PD)
- lower limit = 0.4463" (0.0037" under the nominal 0.4500" PD)
- a difference and "operating range for the lathe user" of 0.0037"

So the limit range is 0.0037" (ie 3.7 "thou") even for the "tightest" of class of thread (3A) - so why not use it. Aim for a PD say 0.4480" and your tolerance zone is 0.4480" +0.0020"/- 0.0.0017"

All of a sudden all the "requirements" for "low tenths" accuracy both in the diameters of the wires and the measured PD's goes right out of the window - poof!!!!

So, if Lazlo were right on the nominal PD (0.4500") he would be right on the upper limit, if he were 0.0002" over he would be outside the limit range and it he were 0.0002" under the nominal PD he would only just be within the upper limit. I have been generous in the +/- 0.0002" bit - which has a limit range of 0.0004" - well outside the inferred "tenth"

If some chose to use higher precision that's quite OK -as it should be - but make sure that you don't settle on the nominal PD as your "accuracy" may well come up from behind and bite you right on the ar$e - hard!!

But to say that others should or must follow and do it is at best some-where between a "big ask" and "dead wrong".

doctor demo
07-15-2010, 10:27 PM
Twohundredthirtyseven posts on thread measuring wires and I still don't know how to use them to measure the threads in a nut.

Steve:D

J Tiers
07-15-2010, 10:36 PM
All thread measuring processes: 3-wire, 1-wire, thread micrometers etc. - all presume and assume that the the thread angle (60* or 55* mostly) are precisely on size, their sides/flanks straight and their axis of symmetry at 90* to the thread/head-stock axis.



Not necessarily...... but substantially...

The problem is what ELSE they may presume....... Things which throw off the measurement by large amounts. Burrs, concentricity, etc.

It may or may not be a big deal in the final number, but it is good to KNOW what other factors are involved, as many of your own posts, Tiffie, have pointed out.

Only the wires largely ignore burrs etc. Mics ride on them, and the one-wire method does also. Thread triangles MAY avoid the burrs.

However, there isn't a lot of point fussing, just because in general you don't need the accuracy.

When you do, the "chinese chopsticks" will work nearly as well as any other...... Particularly if you are cutting the thread on an ancient worn-out machine, or one of those "chinese winches".....


Twohundredthirtyseven posts on thread measuring wires and I still don't know how to use them to measure the threads in a nut.

Actually, I think that was brought up before....... you use them to QC the thread on a gage you make and use to check the nut.

In fact, that is ONE place where it is VERY IMPORTANT to have accurate wires...... Some of the same folks (Tiffie, for example) have made an issue out of having the measuring means accurate to 10X the measurement you are making..... So wires with small errors (well under a tenth) are important for gage-making, since then the only remaining error is in the mic, which typically reads to 0.0001 only.

That suggests just barely being able to reliably QC your gages to 0.001", based on the rule of 10X accuracy.

And, based on teh same rule, the result is, according to Tiffie et al, just barely good enough to check a thread to the 0.005" he has repeatedly mentioned...... 10X more accurate, you know...... and we are stretching the point to use a gage only 5x more accurate.

So, we reach Tiffies 0.005" accuracy result based on wires that are much better than 0.0001" accurate...... Using Tiffie's OWN published and insisted-upon reasoning. :D

oldtiffie
07-15-2010, 10:40 PM
Originally Posted by dp
If you know the diameter of your wire,

You know the diameter at which point? Piano wire, or any drawn wire for that matter (or a nail :rolleyes: ) isn't straight or round either.

That's why thread wires have NIST standards for roundness and taper, as well as nominal size. Those standards from Van Keuren that I posted earlier weren't abitrary -- it's the straightness/roundness/diameter spec to meet the NIST standards.

So picture this scenario: you have three finishing nails that vary in diameter by 50 thou (and that's being very kind). They're mishapen from the drawing and heading operation, and they're not remotely straight. You lay these three nails in your thread grooves, and use a *cough* micrometer to measure the distance between the top two nails, and the bottom nail. That tells you basically, nothing.

You might as well just stick the thread in the nut.

dp (Dennis) is quite correct and lazlo has achieved the difficult feat of having his head in the sand and pi$$ing into the wind and perhaps not even wetting his feet - or is Lazlo female?



So picture this scenario: you have three finishing nails that vary in diameter by 50 thou (and that's being very kind). They're mishapen from the drawing and heading operation, and they're not remotely straight. You lay these three nails in your thread grooves, and use a *cough* micrometer to measure the distance between the top two nails, and the bottom nail.

I don't know that the finishing nails (or framing nails either) were THAT far off in the US - 50 "thou"!!! - if so its a good case for buying "Chinese". I can assure you that in my 90mm>19mm framing and fixing nails for my framing and fixing guns are very consistent as regards size etc. Same for the "hand-driven" nails.

If the difference between the highest and lowest diameters of the 3 wires is not more than 0.0005" (most) the error will be insignificant if you are working in the mid range of the limits for the PD. I expect that the shanks of three new drill from the same pack or batch or even three bits from the same bit of O1/"Silver steel" would all be within 0.0001"/0.0002" so its pretty safe.

My "3-wire" set bought from CDCO tools in the USA are all within 0.0001". I could not see the need for checking any closer - so they are quite adequate - and cheap!!

lazlo
07-15-2010, 10:46 PM
Twohundredthirtyseven posts on thread measuring wires and I still don't know how to use them to measure the threads in a nut.

You don't need them. Just buy finishing nails -- they're much cheaper :D

J Tiers
07-15-2010, 10:49 PM
Any wire will work. Any two wires will work. Any three wires will also work. All that is needed is to know the diameter, and that the diameter is practical for the purpose. It is convenient if they are all the same size but it won't be a show stopper if they are not.

That last bit seems to be odd to me....... I think it IS something of a show-stopper if they are not the same size, as then you are effectively using only two wires, with attendant problems being sure you are measuring on a true diameter, and not angle-wise.

oldtiffie
07-15-2010, 10:51 PM
Twohundredthirtyseven posts on thread measuring wires and I still don't know how to use them to measure the threads in a nut.

Steve:D

Steve.

You will never know how to use 3-wires to measure the thread in a nut directly (they are for external threads only - obviously) - but they CAN be used indirectly for measuring internal threads pretty accurately.

I hope to get to and address that topic in the not too distant future.

Be patient - but don't hold your breath waiting!!!

lazlo
07-15-2010, 10:53 PM
TI think it IS something of a show-stopper if they are not the same size, as then you are effectively using only two wires, with attendant problems being sure you are measuring on a true diameter, and not angle-wise.

It's actually worse than using two thread wires -- if the three wires aren't the same size (let alone, round and straight), then the micrometer isn't even sitting straight relative to the axis of the screw.

dp
07-15-2010, 10:54 PM
That last bit seems to be odd to me....... I think it IS something of a show-stopper if they are not the same size, as then you are effectively using only two wires, with attendant problems being sure you are measuring on a true diameter, and not angle-wise.

If you understand the maths it is all a matter of knocking out an Excel macro. But - I have several spools of wire. I'd bet my next paycheck I could build a go-nogo gage, cut 60' of any spool into 3" sections, get a goodly number of wire sets, certainly within the resolution of my 1" x 0.001 micrometer, and arrive at a bolt that will fit a nut. And I assure you that at no time will those wires leave the bag they are stored in! :)

oldtiffie
07-15-2010, 10:56 PM
Originally Posted by dp
Any wire will work. Any two wires will work. Any three wires will also work. All that is needed is to know the diameter, and that the diameter is practical for the purpose. It is convenient if they are all the same size but it won't be a show stopper if they are not.


That last bit seems to be odd to me....... I think it IS something of a show-stopper if they are not the same size, as then you are effectively using only two wires, with attendant problems being sure you are measuring on a true diameter, and not angle-wise.

Good comment JT.

It is theoretically - and practically - possible to use the 2 wires of the same size and measure over them. The axis of the micrometer will be "off square" by the helix angle of the thread.

You can reduce it back to "square" by multiplying the measured value x Cos helix angle.

dp
07-15-2010, 10:59 PM
It's actually worse than using two thread wires -- if the three wires aren't the same size (let alone, round and straight), then the micrometer isn't even sitting straight relative to the axis of the screw.

Did you know you can relocate any wire to any position and arrive at a useful parameter set? Do you also know that you can even do this with a dowel of known diameter and develop your tables? No need to guess at anything. It's a first principle - somebody had to make those first discoveries, and having done so they left the solution behind. Your math instructors should have done the rest to prepare you to work it out. I'll even bet they did.

oldtiffie
07-15-2010, 11:26 PM
Originally Posted by J Tiers
TI think it IS something of a show-stopper if they are not the same size, as then you are effectively using only two wires, with attendant problems being sure you are measuring on a true diameter, and not angle-wise.


It's actually worse than using two thread wires -- if the three wires aren't the same size (let alone, round and straight), then the micrometer isn't even sitting straight relative to the axis of the screw.

Lazlo.

While that may be theoretical correct the figures to practical purposes are insignificant.

If you were measuring the 0.4500" PD of the 1/2" 13 - UNC bolts (all of them- 1A, 2A and 3A) a "tilt" of 5 degrees would be 0.450 x 1/cos 5* = 0.450 x 1.0038 = 0.4517" - a difference of 0.0017" and if you used the limit tables provided you would still be with limits if you aimed for the mid-point.

It gets a lot less as the "tilt" gets toward zero.

It would require a difference of about 0.007" between adjacent wires at a pitch of 1/13" to get a "tilt" of 5*

So, my guess is that for practical purposes it would not matter if wire error range as regards size was 0.001" and the "out of round" not more than 0.0005". All of my CDCO "Chinese" "3-wires" are well within those zones.

Further, not withstanding some of the "error points" alluded to by JT, it is hard enough to measure over three wires at the best of times, but the other "wild-card" is the ability of the lathe to screw-cut a PD to "tenths" (0.0001") consistently - say just taking off 0.0002" let alone 0.0001" when using a screwing tool.

That's fairly hypothetical as it just is not required if the standard (see Machinery's Handbook) thread PD tolerances and limits are used.

oldtiffie
07-15-2010, 11:40 PM
Originally Posted by lazlo
It's actually worse than using two thread wires -- if the three wires aren't the same size (let alone, round and straight), then the micrometer isn't even sitting straight relative to the axis of the screw.

Did you know you can relocate any wire to any position and arrive at a useful parameter set? Do you also know that you can even do this with a dowel of known diameter and develop your tables? No need to guess at anything. It's a first principle - somebody had to make those first discoveries, and having done so they left the solution behind. Your math instructors should have done the rest to prepare you to work it out. I'll even bet they did.

Quite right Dennis.

You can "reverse engineer" the equations by transposing values if you select any unknown and input all other values.

For example, if I had the measurement over the wires I could chase backwards to see if the thread angle was 55* or 60* etc. But its a pointless exercises in that case as the answer is in MHB - it uses two different sized wires - each of which contacts the thread flanks and project above the bolt major/outside diameter an by measuring over them (one at a time) the "vee" can be solved by geometry using their respective diameters and the distance between their centres.

But the basis of your hypothesis/assertion/point is quire correct.

lazlo
07-15-2010, 11:45 PM
I could build a go-nogo gage, cut 60' of any spool into 3" sections, get a goodly number of wire sets, certainly within the resolution of my 1" x 0.001 micrometer, and arrive at a bolt that will fit a nut.

If you're using a micrometer with a 1 thou resolution, then you have bigger problems. ;)

So on your spool of wire, with a local variance of +/- 40 thou at any inch, and the wire is not even close to round, how will you calculate the diameter?

Will you measure the diameter across the two widest sections of the wire? Or will you spin the wire around in the micrometer until you find a low spot, mark that low spot, and then search your pile of wires for two other sections with matching low spots?

You keep avoiding roundness and straightness, and keep talking about "dowels", but as any machinist knows, very few things in life are round and straight.

oldtiffie
07-15-2010, 11:51 PM
Originally Posted by oldtiffie
...................................

All thread measuring processes: 3-wire, 1-wire, thread micrometers etc. - all presume and assume that the the thread angle (60* or 55* mostly) are precisely on size, their sides/flanks straight and their axis of symmetry at 90* to the thread/head-stock axis.


Not necessarily...... but substantially...

The problem is what ELSE they may presume....... Things which throw off the measurement by large amounts. Burrs, concentricity, etc.

It may or may not be a big deal in the final number, but it is good to KNOW what other factors are involved, as many of your own posts, Tiffie, have pointed out.

Only the wires largely ignore burrs etc. Mics ride on them, and the one-wire method does also. Thread triangles MAY avoid the burrs.

However, there isn't a lot of point fussing, just because in general you don't need the accuracy.

When you do, the "chinese chopsticks" will work nearly as well as any other...... Particularly if you are cutting the thread on an ancient worn-out machine, or one of those "chinese winches".....



Actually, I think that was brought up before....... you use them to QC the thread on a gage you make and use to check the nut.

In fact, that is ONE place where it is VERY IMPORTANT to have accurate wires...... Some of the same folks (Tiffie, for example) have made an issue out of having the measuring means accurate to 10X the measurement you are making..... So wires with small errors (well under a tenth) are important for gage-making, since then the only remaining error is in the mic, which typically reads to 0.0001 only.

That suggests just barely being able to reliably QC your gages to 0.001", based on the rule of 10X accuracy.

And, based on teh same rule, the result is, according to Tiffie et al, just barely good enough to check a thread to the 0.005" he has repeatedly mentioned...... 10X more accurate, you know...... and we are stretching the point to use a gage only 5x more accurate.

So, we reach Tiffies 0.005" accuracy result based on wires that are much better than 0.0001" accurate...... Using Tiffie's OWN published and insisted-upon reasoning. :D

Thanks heaps JT.

There are quite a few very important points that you make when considered individually and collectively.

I will address them and your post later in the day.