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lane
03-08-2008, 11:19 PM
But I got to know. Why do people want to put DRO `s on a lathe . If you are turning shafts with lot of steps yes it may be handy . But a dial indicator will work just fine are per haps a trav a dial. As far as setting the depth of cut the dial on the machine is close enough for 99% of what you do even on a old wore out screw you are only moving in a small amount at a time and should be measuring with micrometers to check. If you need a precise measurement on the cross feed a dial indicator will also work .
So why go to the extra expense on a lathe Besides most of the ones i have seen mounted on lathes the cables get pulled out of the reader heads by the stringy chips .

BobWarfield
03-08-2008, 11:34 PM
Awe come on Lane, I thought you were a nice guy. Did you really set out to call everyone that has a DRO on a lathe stupid and pick a fight with them?

Must be some better use for your time and theirs.

Don't worry, be happy!

BW

darryl
03-08-2008, 11:36 PM
I can see myself finding one useful on the long axis- that's about it. A carriage stop is usually what my need is, though. Sometimes I need to turn a certain length down from a faced end- there a dro would be handy since you can zero, then read the carriage travel directly. But if I had that much of a need for it, I'd already have it in use. And I don't.

Charlie Rose
03-08-2008, 11:50 PM
Had them on the 10EE's at work and were very handy, once you try it you'll not want to go back.
I put a Travadial on my lathe at home and am happy with it but the readout is better, no counting turns for moves over 6" with the readout.

lane
03-08-2008, 11:51 PM
Sorry Bob I was not calling people stupid. I thought it my be a stupid question . But I do not get the reason be hind it .

Ries
03-08-2008, 11:58 PM
All depends on the work you are doing.
If you are making one, very precise, small thing, then its not really as useful as when you are cranking out 50 or 100 parts with relatively loose tolerances, but with steps or multiple grooves or lands.

I could sure see how I would use one a LOT on my lathe- I do a lot of ornamental turning, where as long as its within .010 it would be fine, often on pieces as long as 36", things like table legs- and I spend a lot of time laying them out before they go in the lathe. A DRO would speed stuff like that up quite a bit- but, unfortunately, my lathe is an 18x60- and even if I go with a smaller set of encoders, its still a big, and expensive setup for a DRO- mostly I see sale prices in the $1500 range.
I suppose I dont need 60", most of my work is within 36" of the chuck, and I dont need 18" either, but for a 2 axis DRO, they are still pretty pricy for a big lathe.

radish1us
03-09-2008, 12:16 AM
Lane, the easiest thing for you to do is go find a lathe that has DRO fitted, use it for an hour, then see what you think of them.
Until YOU have tried out a DRO, don't make rash statements about something you DO NOT KNOW NOTHING ABOUT.

regards radish

PS, use 'em at work and they got to be the best thing since canned 'piss, by the way, they are good for 0.01mm if you really need it.

Fasttrack
03-09-2008, 12:18 AM
One of the lathes at school "inherited" a DRO that was damaged. Only the Z axis works. (Well its the longitudinal axis anyhow)

That is dang handy when you don't have a micrometer dial on the longitudinal feed. As others have said, if you have to put say 50 1/8" wide, 1/8" deep grooves along the length of a piece, the DRO makes it pretty quick work. Not sure its neccessarily worth the money, but if you can come up with a cheap used DRO ... then its well worth it! :)

Ken_Shea
03-09-2008, 12:20 AM
I'm am with you Lane, and glad you asked this stupid ? :D

I just love that kind of thing and have tried to talk myself into getting a DRO many times, it always ends up the same, why ?

Ries seems to have the answer, it all depends, for what I seem to do lathe wise it would seem to be just a neat waste of money.

On my manual mill it is invaluable, one would think it would be on a lathe as well, yet I still catch myself scratching my head wondering why.

lugnut
03-09-2008, 12:20 AM
I’m not sure I really need one, but thought it would be nice to have just to back up what I thought I was doing???? :)
mel

Optics Curmudgeon
03-09-2008, 12:26 AM
Sure are handy for some things. I worked at a place in New Jersey that made hydraulic bolt tensioners years ago (they're still there, making do without me since '74), and a DRO sure would have been handy for those internal relief jobs. As it was I made do with a rigged up indicator. Nothing to shake a stick at, especially on the longitudinal axis.

Joe

matador
03-09-2008, 12:41 AM
I think i can live without a dro on my lathe,but I really would like the full setup on my mill-drill,as it would speed up a number of tedious operations .I already have a caliper mounted on the Z axis,and I wouldn't be without it now.

JRouche
03-09-2008, 12:42 AM
Speed.... touch off, zero out and its all just a matter of reading the read-out from there. No diff than having one on the mill.

Sure, the dials on some lathes are pretty darn accurate. My 10EE for example. I felt kinda stupid replacing the super accurate dials (not replacing per say, I didnt remove them LOL) for a digital Newall but once you use it, its hard to even want to look at the dials.. I dont have to count revs either when threading.. JRouche

Ken_Shea
03-09-2008, 12:58 AM
JR,
Speed, I can see that on some procedures, not all but some. On a mill the cutter is usually much larger than one on a lathe so one can crank pretty darn fast and visually see when you are on and then a quick glance to the dial for the preset zero.

Do you catch yourself chasing that .000x x digit?

I take it you feel that they are a definite benefit and worth the cost then ?

Ken

tyrone shewlaces
03-09-2008, 01:03 AM
What I like about them is using offsets. Most of my lathe tools stay mounted in their own holders except for maybe a couple. With offsets you just touch the tools off once (or no more than CNC machines anyways) and enter the appropriate number when you switch holders and BAM! you already know where you are. Enter a work offset for the end of the part you're working on and it shifts Z for all your tools. No touching-off necessary. That alone saves a bunch of time.

I wish I had one at home :(

p.s. Not all DROs have offset capability, but I'm guessing most of the newer ones do. GREAT time & effort saver I think.

Forrest Addy
03-09-2008, 01:08 AM
DEATH to DRO denyers and curmudgeons!!!

Actually DRO's are quite handy. You ehave to spend a little time using them to see just how they take the guesswork out metal removal on any machine even a chop saw. You don't have to figure for backlash for one thing and you always know the tool position from a reference for another. They are not a cure for a worn out machine but on a machine tool in usable condition the amortization for a DRO is 3 months to a year.

Ken_Shea
03-09-2008, 01:11 AM
DEATH to DRO denyers and curmudgeons!!!

Someone please call 911 :D

What the hell is a curmudgeons ? ?

Ken_Shea
03-09-2008, 01:20 AM
curmudgeons

An ill-tempered (and frequently old) person full of stubborn ideas or opinions.

I resemble that remark :D

Mark Hockett
03-09-2008, 01:20 AM
I have one lathe with DRO and one without, I prefer the lathe with. I set the tool to the spindle center line, which takes about the same amount of time as zeroing the dial, and make my cuts. My lathe and DRO are accurate enough where I can inspect the first part and if it's cutting on diameter it will be good for many parts.

My lathe was purchased new in 1996 with the DRO installed and has never had the cables ripped out. I think if the DRO is installed properly there is little chance of that happening.

Most newer DRO's allow for many tool off sets, so each tool can be set to the spindle center line and then called up when needed, with the micrometer dials you reset for each tool which wastes time and allows more room for error. Magnetic dial indicators can get disturbed or bumped or even knocked off the lathe.

I also believe a lathe with a DRO can be more accurate when splitting .001". Most micrometer dials read in thousandths and most DRO's read 4 decimal places and the DRO reads directly from the carriage or cross slide movement not through a screw like the micrometer dials do.

I'm sure most of the people here who are questioning putting a DRO on a lathe have never used a lathe with one. Instead of cut and measure you can measure while you cut. When my DRO is set, whatever diameter it says on the display thats what my micrometer will measure the part at when its done, no more guessing, trying to split the dial or remember if I set the dial to the tool I am using.

I'm not saying I can't make accurate parts without a DRO, it's just much less tedious with the DRO.

Ken_Shea
03-09-2008, 01:29 AM
Well written Mark !

Mark Hockett
03-09-2008, 01:34 AM
Thanks Ken, I have a very hard time trying to put my thoughts into written words, which is probably why I don't post more often.

toastydeath
03-09-2008, 01:54 AM
Good points, Ken.

I like the tool offset feature and Z length adjustment. Like CNC, it serves a pretty good purpose. But like so many things, I don't think a person should learn to use a lathe with a DRO on it. If I had a shop, I'd sure have at least one lathe (either my best lathe or workhorse lathe, or both) with a DRO on it, but certainly not all. Just because sometimes, you want to put grooves in something every .125" for an 20" length, and damn if a dial indicator isn't a pain in the ass for things like that.

Although I kind of sympathize with Lane. I've noticed a trend amongst CNC machinists that if it doesn't have buttons and constant surface speed, they don't want to touch it even though it's a perfectly good machine. Heaven forbid you actually have to turn a handle or attach a dial indicator to something. Shut up and make the part already, geez.

Ken_Shea
03-09-2008, 03:10 AM
toastydeath,
It kinda touches home on what you say about this, at least seemingly, aversion machinist have to anything that doesn't have buttons and whatever. The truth is I always feel more like a machinist (In fact I do not consider my self one) while using my manual lathe, setting and cranking those wheels, ataching dial indicators , stops and so forth. I really enjoy my manual lathe, but am thinking, a DRO may be a nice addition.

Ken

BadDog
03-09-2008, 03:39 AM
Just convenience I would think. No worry about worn screw. Far fewer measurements since the DRO will get you much closer than a worn screw, assuming the same minimal secondary measurement effort on each. Travadial seems to cost more than most inexpensive DRO. Other features like arbitrary zero and switching from direct to actual on demand. Easier for "old eyes". Less mental math too.

All that said, I do just fine on my moderately worn manual lathe with no DRO. I would like one, but don't see the $500 as a good investment based on my needs and use. I also often do not use it on the mill even though it came with one, and the mill is a MUCH more useful place for one, particularly a worn mill...

DickDastardly40
03-09-2008, 04:53 AM
Never used one on a lathe, but skimming over the above there is a facility I've not seen anyone else mention: the easy conversion from imperial to metric if you don't have combinaton dials.

Al

oldtiffie
03-09-2008, 07:14 AM
Never used one on a lathe, but skimming over the above there is a facility I've not seen anyone else mention: the easy conversion from imperial to metric if you don't have combinaton dials.

Al

Thanks Al.

I've been waiting to see when someone would mention some of the benefits of DRO other than zeroing, indexing, and direct measurement.

The main benefit to me - if and when I get off my freckle and put my DRO's on - is that I don't have to optically divide graduations on a hand-wheel. ie if the graduations are in say 0.004", I don't (sorry, won't) have to halve it for 2 thou, quarter it for 1 thou or worse guess between 1/4 (1 thou) and 1/2 (2 thou) for 3/8 ( 1 1/2 thou) etc. It will also eliminate the need to remember that not all lead-screws on a machine are the same - my main lead-screw is 3mm and my cross and top slides are 2mm but one is graduated for 0.02mm (0.0008") and the other for 0.04mm (0.0016").

It's also odd that those who go the "whole hog" (all or nothing) never mention having a DRO on the top/compound slide but put DRO's on the carriage/bed and the carriage/cross-slide.



............................ there is a facility I've not seen anyone else mention: the easy conversion from imperial to metric if you don't have combinaton dials.

Al

As you say, it effectively converts the lathe/mill from inch to metric and vice versa - as required - all conversions done automatically.

As most of my stuff is metric I just do the conversions to metric - roughly at first (1" = 25mm then 1 thou (0.001") = 0.04mm). I then convert exactly to finish off.

I must say that a standard 1" micrometer (0.001" and vernier 0.0001") is much easier to read than a metric micrometer (0.01mm ~ 0.0004") as you need to watch the barrel graduations VERY carefully. But I soon got used to it.

The biggest PITA with "inch" is that so much is given in fractions and has to be converted to decimal inch for most measurements. Its too easy to make a mistake.

I must think about the DRO's (note to self and admonishment - and slapped wrist).

Your Old Dog
03-09-2008, 08:29 AM
I've been trying to figure out how to put cheap caliper styled DRO on my lathe. I felt it would be handy for someone with lessor math skills such as myself. None of the ideas I've come up with look very convienant and for that reason the job still isn't done.

As for Lane's intent. I gave him the benefit of the doubt and figured he meant to say stupid question or something like that. I don't think he has a habit of being on the hunt. JMHO.

John Stevenson
03-09-2008, 08:47 AM
Sorry Bob I was not calling people stupid. I thought it my be a stupid question . But I do not get the reason be hind it .

Lane I can see your reasoning and in some respects I agree as I fitted a Shutatach to my small TOS and when I broke, because it wasn't accurate I never bothered replacing it but may do shortly.

Lathe DRO's are special compared to mill DRO's in that theyread 1/2 the value so my Shumatech which is supposed to be good to 1 thou in fact it was more like nearly 2 gave an error od 3 to 4 thou on diameter.
As most of the work on this lathe is bearing diameters it was a waste of time given the screws are still very accurate after 5 or 6 years.

Wher it di score was roughing out. The TOS has a fine pitch screw and one wind is 1mm so 2mm off diameter.
When roughing and in a rush, remember I make a living at this, going from say a 100mm bar down to 19mm I could finish up 1mm undersize by mis counting the turns with interuptions.
Yes I know I should be more carefull etc, etc, but it has happened.

That's where the DRO came into it's own, a quick visual to get close then finish off on the dials.

After recently fitted one of the new glass scale DRO's to the mill and seeing the difference between that and the old 30 year old glass scale unit is like night and day.

As I run quick change tooling and can have up to 6 tools dedicated to one job I will then be able to marker pen the offset number on the tool holder and just flick between them.

The 1/2 reading won't apply, well it will but it will be accurate enough with these new scales to be acceptable and make the job easier.

They have got to the point now, price wise, that anything else like the digital scale type are just unacceptable on price, accuracy and messing about.


.

IOWOLF
03-09-2008, 08:48 AM
Though personally I don't have any on the lathes. None are good enough.

But if you want one and have the money or reason to put one on your lathe,By all means do it and You will not be Stupid for doing it.:mad:

oldtiffie
03-09-2008, 08:51 AM
Lane is right in one regard - and a very important one at that.

With or without a DRO, I would think that you are still going to have to check with a micrometer or what-ever.

Further, no matter how much a screw/nut is worn it will still be very accurate in any one turn of the lead-screw.

In the end, it will not be the accuracy of the DRO that gets the size required accurate. It will be the accuracy at which the operator and his measuring devices can measure. This applies with or without DRO's.

John Stevenson
03-09-2008, 08:53 AM
The biggest PITA with "inch" is that so much is given in fractions and has to be converted to decimal inch for most measurements. Its too easy to make a mistake.



That is the problem with the imperial system. You have two measurements for every size.

OK 1/2" is fine, the landlubbers definition is one half of one inch, the engineers definition is 0.500"

Now take 1- 33/64" off a drawing. Where is that on your dial ?
OK some people can do this in their head, others can't and this is where errors come in, ask NASA :D

At least with metric there is only one size. there is not other way to write 8.76mm

.

ammcoman2
03-09-2008, 08:59 AM
YOD, This is how I put a caliper (Canadian Tire Special) on my lathe.
http://i56.photobucket.com/albums/g189/ammcoman2/DSC00653.jpg

I did this as I found a few "hiccups" on the leadscrew at certain crucial positions. Of course it only happens when one is trying to fit a bearing or bore for a subsequent press fit!!! It is an 11" Standard Modern so the dial had just a little bit of capacity left.

'Twerks like a charm - so, until I fit a new leadscrew, this mod helps. As each lathe is different you may have to go about the installation in a different way. I probably should have got the calipers with the the larger display - maybe when this one dies an unnatural death due to suffocating in swarf. I ground the pointy bits off first.

Geoff

JCHannum
03-09-2008, 09:03 AM
Lane poses interesting questions like this from time to time, and I can assure you he is more than passingly familiar with using lathes that are equipped with DRO's.

I don't have a DRO my lathe and don't see a great need for one. I do have a DRO on the downfeed of my mill, but that is all, and really have a hard time justifying the need for more than that. I am strictly a home shop, and cannot amortize the purchase of such tooling. It makes no difference how much time might be saved, nothing times nothing is still nothing. At that point the only advantage is convenience.

Many good points have been presented for their use, and all are valid. One bad point that hasn't occurred to me is the susceptability to damage by the occasional bird's nest.

I do have a couple of long travel dial indicators that I have aquired, two with 2" travel and one with 5" travel. They have magnetic backs, and coupled with the carriage stop, they handle any precision location needs very well.

As far as decorative turning like table legs or finials, keep an eye open for a hydraulic tracer. They frequently turn up on eBay for a fraction of the cost of a DRO, and will totally automate the turning of repeat profiles. I picked up one at an auction for $30.00 a couple of months ago and have been having a blast with it.

A slight disclaimer for the Imperial system. Most engineering dimensions these days are given as decimals these days. If a fractional dimension is used, it implies fractional tolerancing. It is a fairly easy matter to convert fractions to decimal, and most machinists can do 32's in their head, good ones can do 64's with no problem. It is simply a part of their language.

Malc-Y
03-09-2008, 10:19 AM
My lathe has a Mitutoyo DRO that was on it when I bought it and as the lathe micrometer dials are metric and most of my work is imperial it is an absolute necessity. There is however one small problem with it, and that is that when I was moving it into my workshop on the trailer, the readout was high enough to be struck by the door lintel and this caused the Z axis readout to cease to function. I have tried to email Mitutoyo regarding getting it fixed but so far they have ignored my emails, perhaps they don't like dealing with private individuals. I get round the problem by switching over the cables from the scales at the back of the readout. as both scales work OK. I would still like to get it working properly though, as I have had to alter the readout so that it reads the actual movement rather that half as the X axis usually does.
If any UK users of this forum know where I can get it repaired I would be most grateful!

Malc. :cool:

Frank Ford
03-09-2008, 10:35 AM
Repeatability.

That's why I like my lathe DRO.

I can trust it for length measurements, but for diameter, well, I must not be dead on center, because I have to check with micrometer often and make small adjustments.

That said, I do small batches of parts - 25-100 at a time - often enough that I really enjoy the ability to set the DRO to zero when I'm at my precise measurement. Then I can repeat operations quickly and easily.

wierdscience
03-09-2008, 10:56 AM
That is the problem with the imperial system. You have two measurements for every size.

OK 1/2" is fine, the landlubbers definition is one half of one inch, the engineers definition is 0.500"

Now take 1- 33/64" off a drawing. Where is that on your dial ?
OK some people can do this in their head, others can't and this is where errors come in, ask NASA :D

At least with metric there is only one size. there is not other way to write 8.76mm

.

John,it's called a wall chart:D


The only prints I have seen done in fractions in any rate were from 1917,everything else is done in decimal inches,only one way to do those also:D

Lane,I figure with the cost of DRO systems coming down there is no reason not to have one.
I want one on the small lathe at work which is the one I use most.Not because I can't use the dials,but because I get interrupted and asked questions 8,000 times daily which tends to derail any train of thought I had as to where I am at on a part.

J Tiers
03-09-2008, 11:49 AM
The only prints I have seen done in fractions in any rate were from 1917,everything else is done in decimal inches,only one way to do those also:D


+100

That old tired "fractional inch" argument............ If someone from the Continent said it, I could forgive them for abysmal ignorance. (At least for distance measurements. Drill sizes are different, although they shouldn't be.)

But John Stevenson said it.

Now, J S is LIVING WHERE THE &^%$#@ FRACTIONAL MEASUREMENTS CAME FROM.

The HOME of OTHER odd measurements like "hogsheads", etc. So he ought to know better.

Besides, I bet he has a 33/64 drill somewhere.

The one place where the argument is reasonable is for the fractional drill series. That is a holdover from where he lives, and isn't particularly handy.

Aside from that, the other drill sizes (number and letter) are just numbers, like "non-significant part numbers", and shouldn't bother anyone. I don't know why nobody ever made decimal drills, but they didn't. Probably because of number size screws etc.

DRO's?

Extra techie stuff, costing more than a machine, and not helping in what most of the readers of our sponsor magazines do.

I'd put one on if I could justify it, but I can't.

Then also, there are the cheap chinese ones and the real ones. The cheapo chinese ones (that's where they come from, folks) only read the dial movement, so they don't give any accuracy at all.

The whole thing is a debate probably better taken over to PM where most members are (or were) commercial machinists.

BobWarfield
03-09-2008, 12:34 PM
In the end, it will not be the accuracy of the DRO that gets the size required accurate. It will be the accuracy at which the operator and his measuring devices can measure. This applies with or without DRO's.

Just remember that the DRO itself is a precision measuring device. YMMV as Sir John's has with the Shumatech, but there are DRO's that will accurately measure how far either axis has moved to a tenth. They're measuring what really happened, while the dial measures what you wanted to have happen.

What it lacks is that it still doesn't measure the part, unless you are at rest. If you're cutting, there is some risk the part has flexed relative to what the DRO measures, so, you should still measure, but as someone said, if you know your machine, and you cut one, and it's right, you know the others will be right too with the DRO.

And now, we haven't heard Lane come back and say whether all this has moved him one way or another in his opinion of DRO's.

Cheers,

BW

mochinist
03-09-2008, 12:46 PM
I wish the dro's had a digital dial display, I have a harder time watching numbers go down sequentially than watching a dial go around.

Peter N
03-09-2008, 12:58 PM
John,it's called a wall chart:D


The only prints I have seen done in fractions in any rate were from 1917,everything else is done in decimal inches,only one way to do those also:D



I dunno - I have a CAD drawing here of a part that we tooled and moulded to fit on the Boeing 747 about 5 years back, and it has both fractions and decimal inches on it.

The part was a handle for the manual fuel dump valve in the wings, and we injection moulded it from 40% carbon fibre filled polyphthlamide to replace an aluminium CNC part.

Interesting story with this. It had an extra 3/8th hole on one flank that needed a secondary sliding core to remove it from the tool, and like everything else it was very tightly tied up with tolerances.
During a design discussion meeting to go through the tooling, I mentioned the extra coring needed for this, and that it would make the tooling a bit awkward to construct, and asked what it was for.
The reply came " It's for the fitter to stick a screwdriver in so he can get extra leverage to turn it if it's tight" :D
We made a jig and drilled the hole post-moulding, after establishing that the 0.005" tolerance wasn't really required.

Peter

John Stevenson
03-09-2008, 01:26 PM
Peter.
I had a similar job.
It was a steel plate laser cut in 3mm steel plate with a series of holes that had to be reamed to a H7 tolerance.
No problem with most as they were 14mm, 16mm and 18mm but one was 28.53mm ??

These is no 28.53 so a 1-1/8" reamer was bought and sent in for regrind to 28.53.

http://www.stevenson-engineers.co.uk/files/reamer.jpg

The first 25 were done and sent out OK.
Next batch of 25 were also OK but next batch were rejected as being too small on the 28.53 hole.

So another new reamer was bought and sent in for regrind. Instead of making a go- no go gauge I called into the customers and asked for whatever fitted this hole.

Puzzled look and the manager disapeared into the drawing office.
came back later and asked "Do you know what this does ?"
"No idea" I replied.

"Well its the backplate for a switch box, the 14mm holes carry a 12mm bolt, the 16mm holes carry a 14mm bolt and the 18mm holes carry a 16mm bolt "

"So what does the 28.53 hole to H7 tolerance carry ? "

"A fücking rubber grommet............................"

Needless to say i didn't get any more of these.

.

wierdscience
03-09-2008, 01:27 PM
I dunno - I have a CAD drawing here of a part that we tooled and moulded to fit on the Boeing 747 about 5 years back, and it has both fractions and decimal inches on it.

The part was a handle for the manual fuel dump valve in the wings, and we injection moulded it from 40% carbon fibre filled polyphthlamide to replace an aluminium CNC part.

Interesting story with this. It had an extra 3/8th hole on one flank that needed a secondary sliding core to remove it from the tool, and like everything else it was very tightly tied up with tolerances.
During a design discussion meeting to go through the tooling, I mentioned the extra coring needed for this, and that it would make the tooling a bit awkward to construct, and asked what it was for.
The reply came " It's for the fitter to stick a screwdriver in so he can get extra leverage to turn it if it's tight" :D
We made a jig and drilled the hole post-moulding, after establishing that the 0.005" tolerance wasn't really required.

Peter

No system of measurement can overcome the engineer's need to be silly.

Once had a print of some pins to be made with an OD tolerance listed as +/-.00005",nice,but I knew they were track pins for an excavator;)

Last example of this was a drawing that included both inch and metric demensions(not dual read,just mixed between views).I joked with my helper that I converted the inches to mm and the mm to inches as not to cause confusion:D

Fractions and decimal inches I regularly see on a print,just never fractions by themselves unless it's a woodworking job.Fractional only prints went out with piston steam engines.

Most times you will see fractions along side decimal inches to prevent mis-reads since the decimals repeat. .0625" and .625" can be confused readily if someone is in a hurry.Then metric dimensions can also be a problem,I once worked with a Polish machinist that confused 12mm with 12cm,12.00 and 12.00 look a lot alike afterall:D

tattoomike68
03-09-2008, 02:07 PM
I would think a dro on a lathe would be a luxury item. I want one.

hell, some old lathes did not even have graduated dials, a dro would be great on those.

Peter N
03-09-2008, 02:10 PM
My new (old) lathe has dual metric and imperial dials.
Handy.

Peter

wierdscience
03-09-2008, 02:59 PM
My new (old) lathe has dual metric and imperial dials.
Handy.

Peter

Which scale goes full way around to zero,inch or metric?Reason I ask is depending on leadscrew one would be accurate over the full range of the screw while the other only for one revolution.

Ian B
03-09-2008, 03:16 PM
Wierd,

I also have a lathe with dual imperial / metric dials. They're both accurate, however many times you turn the handle. Mine's an imperial machine, ie. the feed screws are 10tpi on the cross slide, 4tpi leadscrew.

The way they do it is by gearing the dials together, and they turn at a fractionally different speed. In the case of the cross slide, the imperial dial (which is keyed to the feed screw) has an internal gear with 127 teeth. The metric ring has 125 internal teeth. There's a 20 tooth pinion joining them (the difference in pitch diameters between the 125 & 127 is negligible).

Mine had stripped one of the gearwheels, so I made a new gear ring:
http://smg.photobucket.com/albums/1003/IanBartlett/?action=view&current=Finishedring.jpg

Ian

Mark Hockett
03-09-2008, 04:25 PM
Then also, there are the cheap Chinese ones and the real ones. The cheapo chinese ones (that's where they come from, folks) only read the dial movement, so they don't give any accuracy at all.




J Tiers,
There are actually some very nice DRO's coming out of China. My friend just installed one on his lathe and it is much nicer than the USA made one I have on my lathe. Time will tell how long it holds up but it is a glass scale DRO with .0002" resolution and looks like its decent quality. I look at some of the other electronic items coming out of China, like most of the computer stuff we use, and have more faith in that stuff than their mechanical stuff. Here is the one he has,
http://cgi.ebay.com/0-0002-2-AXIS-DRO-LATHE-PACKAGE-GLASS-SCALE-ISO9001_W0QQitemZ330199712374QQihZ014QQcategoryZ97 230QQrdZ1QQssPageNameZWD1VQQ_trksidZp1638.m118.l12 47QQcmdZViewItem


My hope is the competition from the Chinese DRO's will cause the other manufacturer's to find ways to lower their prices to compete and I can get a Newell or something comparable for a reasonable price. As I do make my living with my lathe the DRO pays for itself pretty quick with quicker part turn around times and less scrap.

Smokedaddy
03-09-2008, 04:41 PM
Why do people want to put DRO `s on a lathe.


Lane,

How about a picture of your setup for us novices then that want a DRO and don't want to be stupid? <smile>

-SD:

lane
03-09-2008, 06:38 PM
[QUOTE=radish1us]Lane, the easiest thing for you to do is go find a lathe that has DRO fitted, use it for an hour, then see what you think of them.
Until YOU have tried out a DRO, don't make rash statements about something you DO NOT KNOW NOTHING ABOUT.

regards radish

PS, use 'em at work and they got to be the best thing since canned 'piss, by the way, they are good for 0.01mm if you really need it.[/QUOTE

Well I have used them at work . Had them on all the lathes at a few shops I worked in . But pre fer a trav a dial over the DRO. besides most of the time they get broke . The big harry chips get caught around the cables and pull the wires out of the reader heads . They were always replacing them. I DO know about them just cant under stand the reason on lathes . Mill`s would not run one with out it.

lane
03-09-2008, 06:43 PM
curmudgeons

An ill-tempered (and frequently old) person full of stubborn ideas or opinions.

I resemble that remark :D
ME i guess.

Fasttrack
03-09-2008, 06:45 PM
Thats interesting - i've never used a DRO on a mill and so have gotten accustomed to reading dials. The only reason i like a DRO on a lathe is just for that dern longitudinal axis since many lathes don't have a dial on it. I guess a trav-a-dial would work just as well as a DRO and probably more accurate. Dial-indicators are a pain-in-the-a** compared to the DRO (or trav-a-dial) since you have to use gauge blocks for long distances and make sure you don't accidently bump the mag base or etc. I always worry using one for some reason.

I agree with you though - seems like its not really neccessary. Cool if you have lots of money to spare, but i think most home-shop guys could find many other tools they would rather have! (I know i could, anyway) :)

lane
03-09-2008, 06:51 PM
I've been trying to figure out how to put cheap caliper styled DRO on my lathe. I felt it would be handy for someone with lessor math skills such as myself. None of the ideas I've come up with look very convienant and for that reason the job still isn't done.

As for Lane's intent. I gave him the benefit of the doubt and figured he meant to say stupid question or something like that. I don't think he has a habit of being on the hunt. JMHO.


Correct . I meant Stupid Question Or this could be a stupid question . Or I need and answer.

HSS
03-09-2008, 07:00 PM
First improvement to my machine was DRO. I love the thing for bolt circles, but I still back it up with a mic.

lane
03-09-2008, 07:26 PM
Lane poses interesting questions like this from time to time, and I can assure you he is more than passingly familiar with using lathes that are equipped with DRO's.

I don't have a DRO my lathe and don't see a great need for one. I do have a DRO on the downfeed of my mill, but that is all, and really have a hard time justifying the need for more than that. I am strictly a home shop, and cannot amortize the purchase of such tooling. It makes no difference how much time might be saved, nothing times nothing is still nothing. At that point the only advantage is convenience.

Many good points have been presented for their use, and all are valid. One bad point that hasn't occurred to me is the susceptability to damage by the occasional bird's nest.

I do have a couple of long travel dial indicators that I have aquired, two with 2" travel and one with 5" travel. They have magnetic backs, and coupled with the carriage stop, they handle any precision location needs very well.

As far as decorative turning like table legs or finials, keep an eye open for a hydraulic tracer. They frequently turn up on eBay for a fraction of the cost of a DRO, and will totally automate the turning of repeat profiles. I picked up one at an auction for $30.00 a couple of months ago and have been having a blast with it.

A slight disclaimer for the Imperial system. Most engineering dimensions these days are given as decimals these days. If a fractional dimension is used, it implies fractional tolerancing. It is a fairly easy matter to convert fractions to decimal, and most machinists can do 32's in their head, good ones can do 64's with no problem. It is simply a part of their language.


Very well said JC. We think along the same lines.

wierdscience
03-09-2008, 07:34 PM
Wierd,

I also have a lathe with dual imperial / metric dials. They're both accurate, however many times you turn the handle. Mine's an imperial machine, ie. the feed screws are 10tpi on the cross slide, 4tpi leadscrew.

The way they do it is by gearing the dials together, and they turn at a fractionally different speed. In the case of the cross slide, the imperial dial (which is keyed to the feed screw) has an internal gear with 127 teeth. The metric ring has 125 internal teeth. There's a 20 tooth pinion joining them (the difference in pitch diameters between the 125 & 127 is negligible).

Mine had stripped one of the gearwheels, so I made a new gear ring:
http://smg.photobucket.com/albums/1003/IanBartlett/?action=view&current=Finishedring.jpg

Ian

Ahhh...geared dialsthat's a different animal than the usual dual scale models.

Nice job on the RG btw!

J Tiers
03-09-2008, 07:41 PM
J Tiers,
There are actually some very nice DRO's coming out of China. My friend just installed one on his lathe and it is much nicer than the USA made one I have on my lathe. Time will tell how long it holds up but it is a glass scale DRO with .0002" resolution and looks like its decent quality.

Well, you missed the "CHEAPO" part...... CHEAP chinese stuff varies from bad to totally unsuitable.

GOOD chinese stuff is good, but costs much closer to any other price.

lane
03-09-2008, 07:49 PM
Well I guess it boils down to what ever Makes you happy. Looks like a stand off. If you got one you love it . If you don`t you just don`t know any better. I will just keep my Trav A Dial `s.
I only plan to build one are two parts the same any way.( I DON`T DO NO Production.) My motto is I will build any thing once nothing twice. Its Hell to be Arrogant
But i needed to know what your thoughts were on the subject. I read about every one lots of newbies wanting DRO on their lathes .Just trying to find out if this old fool was missing something , don`t think so .

oldtiffie
03-09-2008, 08:00 PM
+100
.....................................
...................................

DRO's?

Extra techie stuff, costing more than a machine, and not helping in what most of the readers of our sponsor magazines do.

I'd put one on if I could justify it, but I can't.

Then also, there are the cheap chinese ones and the real ones. The cheapo chinese ones (that's where they come from, folks) only read the dial movement, so they don't give any accuracy at all.

The whole thing is a debate probably better taken over to PM where most members are (or were) commercial machinists.

Hi Jerry.

I thought I'd bring you up to date with at least some of the DRO's coming from China.

I am not slamming anything not from China nor am I promoting anything from China. I am just advising of what is available that I have been interested in that is available in OZ.

As said in other threads, I have a full 3-axis set of "Easson" DRO's for my HF-45 vertical column mill. They have been sitting in a box on a shelf in my shop for at least 6 and probably 12 months. I am still thinking about putting them on as I get by pretty well without them so far, but I can see the advantages of them.

The Easson web site and DRO details are at:
http://www.easson-co.com/product.asp?skin=1&lan=zh-en&id=7

It's worthwhile having a look at their other products - on the menu on the left.

Costs here are at:
http://www.machineryhouse.com.au/sample_2/Catalogues/Metalworking/44.html

I also have the linear (digital caliper type) DRO's for my HF-45 and the remote 1 and 2 line repeater readouts as well as per the bottom line of the following link:
http://www.machineryhouse.com.au/sample_2/Catalogues/Metalworking/43.html

I bought them first - about 2 years ago but never used them. I may use them on my lathe - when-ever.

The remote counters are great as the DRO placement is not dependent upon nor hindered by any requirement to be able to see the DRO. It is an excellent alternative set-up to an item as expensive as the Easson sets.

The AU$ is about US$0.93 at present so parity is near enough for this discussion.

You will have gathered that we are in the same camp as regards the urgency to fit DRO's.

I am not so sure that this thread or discussion should be sent to PM as from what I gather from advice here is that anything "China" is a "no-no".

I am very satisfied with the discussion here, irrespective of whether members are or have been "Professional Machinists" or not.

Most here, so far as I am aware are not in business. Many are retired, few can "write off" the cost or amortize it against a paying job or a business or get a tax-break, and many buy their stuff from wages/salary and/or the family/domestic budget.

On that basis, I consider that this forum is ideal for this discussion by and for machinists at all levels of skills and resources.

oldtiffie
03-09-2008, 08:19 PM
Peter.

..................................................
.................................................. .

Puzzled look and the manager disapeared into the drawing office.
came back later and asked "Do you know what this does ?"
"No idea" I replied.

"Well its the backplate for a switch box, the 14mm holes carry a 12mm bolt, the 16mm holes carry a 14mm bolt and the 18mm holes carry a 16mm bolt "

"So what does the 28.53 hole to H7 tolerance carry ? "

"A fücking rubber grommet............................"

Needless to say i didn't get any more of these.

.

Hi John.


"So what does the 28.53 hole to H7 tolerance carry ? "

"A fücking rubber grommet............................"

Luvved it!!

A H7 tolerance on a hole for a condom no less!!

What size and what tolerance was on the "Shaft" component may I venture to ask?

The "Hole" tolerance is irrelevant as if it is the "hole" I think it refers to, I have good advice that it will stretch a yard (914.4mm) before it will tear an inch (25.4mm)!!

You will appreciate that the metric measurements are "hard" and not "soft" conversions but with adequate but rigid rounding.

PS. In the event of any tearing DO NOT use "Durex" from OZ as it is a brand of adhesive tape here!!! We therefore buy "Durex" by the roll here and not by "each" or packet as in the UK.

(For non-UK or non-OZ readers, "Durex" is/was(?) a condom in UK and you will appreciate why "condominiums" as in the US are not abbreviated to "condoms" here).

J Tiers
03-09-2008, 08:25 PM
Weeellllll, some of the cheapo non-direct-reading "DROs" are pretty nasty, as mentioned .. but it isn't a china knock, see above for disclaimer...... just a "CHEAP" chinese stuff knock.

ADDED NOTE: There are a number of "DRO" systems which do NOT read movement, but ONLY read dial turns, assuming that the screw is good, has no backlash, etc. Naturally, they are WORTH NO MORE THAN READABLE DIALS.

GOOD chinese stuff (not made primarily for price) is fine, with maybe SOME issues. DROs with scales that read independently should be fine.

China stuff is FINE at PM..... Just not the aggressively beginner home-shop stuff such as "minilathes" and "9 x 20" , "3 in 1" etc.

Lots of the folks over there use AT WORK 16 x ?? machines from Jet, Birmingham, or others which are surely china made, but of a totally different sort from the "9 x 20" stuff.

HSS
03-09-2008, 08:42 PM
My chinese dro works ok, but the manual written in chinglish is a POS. Very hard to understand. It's mostly trial and error. That's why I still go to the mic's on close work tolerances.

oldtiffie
03-09-2008, 09:07 PM
I've seen a lot of discussion on this forum regarding axial measurement - ie non "diameter" stuff, I mean measuring "distance" if you like.

This is the traditional role of the ubiquitous "Engineer's Rule/r" that was or in either in everybody's over-alls/cover-alls breast or side pocket.

It is almost invariably steel and calibrated in 1/32" and 1/64". The scales at best are hard to read when in new condition even in good lighting.

I've chucked mine as I prefer to use a white plastic folding Carpenter's metric rule calibrated to 10, 5 and 1mm.

Despite what some may say, the calibrations are remarkably accurate and being black on a white back-ground are the ultimate/optimum contrast. They work very well in any light. I have about 3 in very good condition and several that I have broken. The "short end" 250mm is ideal on the mill or lathe when accuracy to say 0.5mm (0.020") or even 0.25mm (0.010") is required.

The 1 metre long metric rules are calibrated in "inch" on the reverse side so "conversions" are instant and easy.

1mm at 0.03937" is near enough to 0.040" so I can "split" that 40 into 20, 10 or 5 easily - others need a bit of care and concentration. And it sure beats the hell out of a steel rule and its 1/32" and 1/64" calibrations. I used to have a depth guage the rule on which was calibrated to 1/100" on one side and mm on the other - 50 years ago, but it "got the flick" too as it was almost impossible to read accurately and repeatedly.

I can and do use my threading dial to indicate travel along my lathe bed at times as it does a fair job at surprisingly accurate work. Just put a mark on the bed, move the carriage, check with a rule and then use the threading dial.

Sure, its not the optimum way to go, but it has worked often enough when needed.

But back to the DRO discussion:
- don't I like DRO's or am I against them? No - not at all.
- have I got any DRO's? Yes - see previous posts.
- why haven't I fitted them? Lots of reasons - laziness included I suppose.
- am I going to fit the DRO's - see previous answer.
- when am I going to fit them? When it suits or is needed and "in the fullness of time".

Rich Carlstedt
03-09-2008, 10:43 PM
I Can't believe... Post number 63 and no one has mentioned it..
"And the number one reason for having DRO's on a Lathe ??"

Why "backlash" of course.tells you where you are !

and If they come out with a 10 inch long dial indicator, that doesn't get in the way, is easy to mount, will not attract ferrious chips, and is readable by someone who has not had 20-20 vision in 30 years, and does not "accidently " move on you, it might,..... just might...... be better, but I doubt it.
Dial indicators are fragile, are prone to stick at times, and you still have to count the revs"

" And the number two reason for a DRO on a lathe ???? "

Error rate is substatially reduced !.
At work, we recorded iimproved production by 30 percent on Lathes equiped with DRO's AND THEN
......we noticed a reduction in Quality problems..
enough said.
Rich

hands down...its like asking if you should get a radio in your next car ??? ..
"You don't need it to drive "....
yes, true, , but it's nice to enjoy the ride !

Carld
03-09-2008, 10:54 PM
I have been avoiding this thread like the plague but here goes.

If you have ever done a shaft that requires step shoulder/diameters and snap ring grooves you would love the hell out of a DRO on the carriage travel. You don't really need one on the crossfeed or compound. I have always used a dial indicator on the crossfeed and compound if needed but I can see where some would like to have a readout on all three.

I have an old DRO on my mill that only the long travel works. I have threatened several time to put it on my lathe and when I buy a new DRO for the mill I'll probably put it on the lathe.

It sure would be nice to "0" off the end of a shaft and start machining all the steps, grooves, etc. toward the chuck.

I can see a very important use for a DRO on the carriage travel for me.

As far as the crossfeed and compound on my lathe what you dial in is what you get.

oldtiffie
03-09-2008, 11:23 PM
I Can't believe... Post number 63 and no one has mentioned it..
"And the number one reason for having DRO's on a Lathe ??"

Why "backlash" of course.tells you where you are !

and If they come out with a 10 inch long dial indicator, that doesn't get in the way, is easy to mount, will not attract ferrous chips, and is readable by someone who has not had 20-20 vision in 30 years, and does not "accidently " move on you, it might,..... just might...... be better, but I doubt it.
Dial indicators are fragile, are prone to stick at times, and you still have to count the revs"

" And the number two reason for a DRO on a lathe ???? "

Error rate is substatially reduced !.
At work, we recorded iimproved production by 30 percent on Lathes equiped with DRO's AND THEN
......we noticed a reduction in Quality problems..
enough said.
Rich

hands down...its like asking if you should get a radio in your next car ??? ..
"You don't need it to drive "....
yes, true, , but it's nice to enjoy the ride !

Thanks Rich - good post.

You raise a very important point re. "backlash" but it may be the cause of quite some "angst".

The - say - cross-slide DRO will certainly tell you how much relative movement there is between the cross-slide and the saddle/carriage - to a very high order of accuracy - no question.

It will NOT counter or cancel out back-lash.

Unless you have a very accurate and very well installed ball-screw there WILL be back-lash.

The only way to counter back-lash is in the traditional and time-honored way.

That is to withdraw the tool past the back-lash - if required - and then feed in toward the job - and then the machined result will match the accuracy of the DRO.

To do otherwise will result in a theoretical error of twice the back-lash.

Some may see the DRO as the panacea for all the ills of the world in machining. It is that panacea for many, even most things - but not all.

These same people may be lulled into a false sense of security if they think and rely on positioning the cross-slide from either direction - and ignoring back-lash - is OK "because my DRO says so".

J Tiers
03-09-2008, 11:38 PM
These same people may be lulled into a false sense of security if they think and rely on positioning the cross-slide from either direction - and ignoring back-lash - is OK "because my DRO says so".

But, aside from the cheapo "dial type DROs" I mentioned above. EVERY OTHER DRO will promptly TELL YOU that your crosslide has moved.

So NO "false sense of security is involved.

I myself have NO INTENTION of installing ANY DRO. This is not from a thought that they are useless, etc. FAR FROM IT.

But I don't want to install one on a machine that does not (yet, at least) justify it by its actual worth and quality. It is only a 10" Logan, nice enough, and capable of fine work, but worth less than the DRO. Nor does my use and need justify it.

oldtiffie
03-10-2008, 12:04 AM
These same people may be lulled into a false sense of security if they think and rely on positioning the cross-slide from either direction - and ignoring back-lash - is OK "because my DRO says so".


But, aside from the cheapo "dial type DROs" I mentioned above. EVERY OTHER DRO will promptly TELL YOU that your crosslide has moved.

So NO "false sense of security is involved.

I myself have NO INTENTION of installing ANY DRO. This is not from a thought that they are useless, etc. FAR FROM IT.

But I don't want to install one on a machine that does not (yet, at least) justify it by its actual worth and quality. It is only a 10" Logan, nice enough, and capable of fine work, but worth less than the DRO. Nor does my use and need justify it.

Thanks Jerry.

I agree with you entirely if, and only if, the operator keeps checking the DRO for "shift".

I suspect that a lot will/may just set the cross-slide for/with the DRO and just concentrate on the cutting etc. and find out the effects of neglecting back-lash the 'hard way".

Same applies to "dial" work if back-lash is not allowed for.

JRouche
03-10-2008, 12:22 AM
But, aside from the cheapo "dial type DROs" I mentioned above. EVERY OTHER DRO will promptly TELL YOU that your crosslide has moved.


Exactly!!! They are not gonna compensate for a loose machine but it will tell you where you are at, everytime..

Same with CNC machines. They dont make a machine more accurate, they just monitor where the tool or cutter is at a certain point. And the ball screws are there to help with backlash but you still need the encoder to give the computer (in the case of DROs, the computer is the operator) a definitive point where the cutter is at..

Im all for bringing in precision electronics into the work place.. Just makes sense.. JRouche