PDA

View Full Version : Take up knitting or use a gas axe ?



John Stevenson
01-31-2008, 07:31 PM
Spotted this tonight on a so called maching forum.


Dials are of somewhat limited use for accurate work ... they're designed for lopping off .250", but do poorly when you want to take of .0250". I've run older machines where the engraving was invisible, and newer lathes that were pristine ... it really doesn't much matter.

What a hoot.................

.

sconisbee
01-31-2008, 07:35 PM
lol! so according to them before the days of DRO's and the like nobody could take off .0250"?:rolleyes: they need a bump on the noggin to knock some sense into them!

Bguns
01-31-2008, 07:37 PM
What happens when his precious DRO gets knocked out by a power surge???

I am sure most of us split that shabby .001 graduation on the dial into smaller bits once in a while, and do a decent job of it.....

And of course the old set the compound over trick, would confuse him even more.... An average lathe can be set to get millionths of an inch of feed.. GASP :) All with a simple Dial.....




and some math.....

wierdscience
01-31-2008, 07:41 PM
.025"? Must be kidding right? Screw the dials,I can hit that by eye.

John Stevenson
01-31-2008, 07:42 PM
Well in all fairness it was on a welding and fabricating forum with a sub forum for machining and knuckle dragging :D

.

sconisbee
01-31-2008, 07:45 PM
lmao! ahhh well nuff said, isnt welding the art where plus or minus 10mm is precise?.....wait no that was just my old boss, never mind!.:D

sconisbee
01-31-2008, 07:53 PM
What happens when his precious DRO gets knocked out by a power surge???


Now that got me thinking, i have to use the dials on my mill a whole lot while i find somewhere warm to put the DRO readout till it warms up enough to work. its wierd, its all jumpy and skitterish untill its warmed up (and i mean its entirety and not just letting the display warm up) its an ancient but still quite accurate newall, works fine just mildly irritating on cold mornings:rolleyes:

I'm rather fond of the dials myself tho if im not in a hurry that is

mochinist
01-31-2008, 08:06 PM
lmao thats great



My teacher wouldnt let me use the dro for the first few months, only dials and mag bases with indicators:) and of course scribed lines

macona
01-31-2008, 08:07 PM
The electrolytic caps in it are shot. Replace them and bet it will work normal. Electrolytic caps have a pretty short life.

sconisbee
01-31-2008, 08:09 PM
The electrolytic caps in it are shot. Replace them and bet it will work normal. Electrolytic caps have a pretty short life.

ahhhhhhhhh damn i never would have thought of that! thankyou!, i got a ton of spare caps here so i might do that this weekend. nice thing about this DRO is 2 screws and the axis boards just slide out nice and easy. all the electronics are modular.

tony ennis
01-31-2008, 08:40 PM
And of course the old set the compound over trick, would confuse him even more.... An average lathe can be set to get millionths of an inch of feed.. GASP All with a simple Dial.....

Ok, I'm a newb. Spill the beans!

jkilroy
01-31-2008, 08:57 PM
Shoot, I don't even start looking at the dials till I'm better than .025, at least on OD.

SGW
01-31-2008, 09:16 PM
Millionths may be a bit optimistic, as at that level temperature differences tend to overwhelm the measurement unless you're really careful, but ten-thousandths isn't a big deal. Set the compound to (about) 6 degrees from being parallel to the lathe spindle axis. SIN(6) is (about) .1, so for every thou you feed using the dial of the compound, you'll feed in about 0.0001".

You can work out the exact numbers, but that's the general idea.

torker
01-31-2008, 11:02 PM
lmao! ahhh well nuff said, isnt welding the art where plus or minus 10mm is precise?.....wait no that was just my old boss, never mind!.:D
That is incorrect!
The proper saying is...
(with a mig machine) "Close fit hell! As long as the two pieces of steel are in the same room, we can join them together" :D

Timewarp
01-31-2008, 11:36 PM
Torker, If you can walk across it, we can weld across it!

J Tiers
02-01-2008, 12:06 AM
Not sure the post is TOTALLY off........ I've seen machines where the dial, if cranked in 0.040, actually decreased diameter only about 0.075, not the expected 0.080.

I kinda liked that in a way, it was built in insurance against over-cutting. At least until you got well onto the good part of the screw, then it was nearly right on, and you'd be undersize if you cranked on a little "windage".

And, perhaps they typo'd and really meant millimeters. 0.25 MM is a respectable 0.010 or so, and 0.025mm is getting reasonably precise. (Ok, I don't believe it either, I was trying to be nice).

Ian B
02-01-2008, 02:22 AM
One thing on dials caught me out recently. My Myford ML10 has the cross slide dial calibrated in thous. Wind on a cut of 10 thou, the cross slide moves 10 thou(ish), the work reduces in diameter by 20 thou. No problem - I was used to this.

Now, my new lathe, a Harrison M400 has been 'idiot proofed' - wind on a 10 thou cut, diameter of the work reduces by 10 thou. The dial indicates twice the cross slide movement.

Fine when you know, good to bear in mind if you have to move to a new lathe.

Ian

Bguns
02-01-2008, 06:22 AM
I said Millionths and meant, (of course in a perfect world of 68 degrees) Still air, vibration isolated room, insulated compound crank handle, Cool LED light from 2 meters away, etc :)

Let the guy with a standard ol DRO measure it :)

tony ennis
02-01-2008, 09:01 AM
Set the compound to (about) 6 degrees from being parallel...

zomg! My brain just got bigger!

Timleech
02-01-2008, 09:12 AM
One thing on dials caught me out recently. My Myford ML10 has the cross slide dial calibrated in thous. Wind on a cut of 10 thou, the cross slide moves 10 thou(ish), the work reduces in diameter by 20 thou. No problem - I was used to this.

Now, my new lathe, a Harrison M400 has been 'idiot proofed' - wind on a 10 thou cut, diameter of the work reduces by 10 thou. The dial indicates twice the cross slide movement.

Fine when you know, good to bear in mind if you have to move to a new lathe.

Ian

My DSG has radius readings, the CVA next to it diameter readings. I'm used to it now, but it'll be better when I've got DROs fitted to both.

Ian, in answer to your earlier question, the DSG is fine for what I need. It's well-used, nowhere near its first flush of youth, but I knew that before buying it. I still need to tweak the levelling a bit. It's the right size for what I need, has Taper turning (which I need) and it's nice to use. If I need to do more accurate work, it's usually within the capacity of the CVA. I sometimes rough stuff out with the DSG, which can do some serious metal removal, before finishing it on the CVA.

Tim

Evan
02-01-2008, 09:30 AM
Electrolytic caps have a pretty short life.
Especially those made between the fall of 1999 and the end of 2003. During that time about 2/3rds of world production which came from about six main manufacturers in Taiwan were made with a faulty electrolyte formula. This was a case of either industrial sabotage or espionage, nobody will ever know for sure. A lab assistant stole the formula from a company in Japan who are the arch rivals of the Taiwanese in capacitor production. The formula was sold to the major manufacturers in Taiwan. It had passed all tests (but one) and seem to be a significant improvement for the production of low ESR capacitors, the type used in filtering power supplies and bypass capacitors on electronics.

The one test that it hadn't passed was life testing and the electrolyte fails within three to five years at most. The failed units are easy to diagnose. The ones that have definitely failed have slightly bulging tops due to excess pressure from overheated electrolyte. They may even leak or explode in some cases but the slightest amount of bulging in the scored top is an indication of failure.

http://vts.bc.ca/pics3/capsbad.jpg

SGW
02-01-2008, 09:42 AM
Actually, now that you mention it, I think Moore Special Tool Co. did indeed build machines with dial graduations to millionths.

A.K. Boomer
02-01-2008, 09:44 AM
Not sure the post is TOTALLY off........ I've seen machines where the dial, if cranked in 0.040, actually decreased diameter only about 0.075, not the expected 0.080.

I kinda liked that in a way, it was built in insurance against over-cutting. At least until you got well onto the good part of the screw, then it was nearly right on, and you'd be undersize if you cranked on a little "windage".

And, perhaps they typo'd and really meant millimeters. 0.25 MM is a respectable 0.010 or so, and 0.025mm is getting reasonably precise. (Ok, I don't believe it either, I was trying to be nice).


Agree'd JT, It depends what your using it for, On an old mill I wouldnt trust the dials for anything but "short work", they are almost always "progressive" ------ Lazy in the middle and progressive at the ends, If your dealing with a little 2" piece none of this matters much, If your starting off where the leads are worn the most ( Usually in the middle) and then moving to one end of the table to make the other cut or hole the cut will almost always be overshot --- even if the machine has been used by a very experienced machinist that has made an attempt to distribute the wear on the leads evenly over its lifetime by using the ends of the table frequently the middle still ends up doing double time, lead nuts are not the only thing that wears, lead screws also give up their material over time, the nuts are adjustable --- the leads succumb to getting progressive,

If you have an older machine you can determine just how bad your lead screws are progressive, take a series of measurements of dial free play from middle of machine to the ends of table travel, if you have progressive leads you will see a DECREASE in dial free play towards the ends of the table -- take the variance between the largest and smallest and divide by two, Now at least you have a crap shoot figure that you can utilize for long work, and even a crap shoot figure for the medium stuff --- So glad I got a DRO so I dont have to go through that crap... personally --- I have better things to do ---- do I still know my machine? I may not know the dials as well but because I get to focus on other aspects of it I believe I know it better in other area's, Yet as you can see -- if a bolt of lightening took out the Jenix I would have no problem finishing the Job with the dials, that is as long as im not in a hurry;)

oil mac
02-01-2008, 12:25 PM
Absolutely mind boggling, the statements one reads nowadays, What the damn is the point of having the dials graduated in thous, if in certain quarters it is assumed one only can work to an accuracy of 0.250" Why not make the graduations in 0.500" divisions :D ? Makes one wonder how the old boys in the 1840-1920/s made lovely machines frequently only working with calipers, and still working to half thou fits! Where is the western world going ?
Hmmmm- Think i will go out & cut the dials of my Holbrook :eek:

dick ellis
02-01-2008, 12:35 PM
I have a VDF lathe that has a D.R.P. (deutch Reich Patent) that has the graduation marks on the dials in 0ne 400th of an inch.
Ain' life fun.
Dick

macona
02-01-2008, 01:00 PM
A lab assistant stole the formula from a company in Japan who are the arch rivals of the Taiwanese in capacitor production.

From what I read (Think wiki maybe.) they guy didnt get the last page of the formula that had the final bit of info they needed. Oh well...

In operation electrolytics have about a 15-20 year life if kept cool it seems. Raise the temp and all bets are off.

Usually they dont fail like the taiwan caps did but either short out internally or dry out. The electrolyte is water bases so nothing lasts forever. There are plans out there to make in circuit ESR testers that can help determine if a cap is still good. But if the unit is old enough I just go through and make a list and order a new set of caps for it.

As for the dials the dials on my EE are direct reading. Take .2 off on the dial get .2 off the diameter. I did one day keep making a part consistently undersize. My DRO does not keep its setting after power off and it reverted to radius mode instead of diameter. Found out later the power had gone off during the day. OOPS!

Evan
02-01-2008, 01:11 PM
From what I read (Think wiki maybe.) they guy didnt get the last page of the formula that had the final bit of info they needed. Oh well...

Perhaps that was entirely intentional?

sconisbee
02-01-2008, 01:40 PM
Thanks to macona my DRO is up and running 100% again, you were spot on about the caps.

As for dials, one of my lathes has radius dials and the other diameter dials and it took me a loong time to get used to quickly switching between the two before mistakes stopped:rolleyes: tho one of the machines now has a new DRO i got last december on it.

bhjones
02-01-2008, 02:19 PM
Please elaborate on this. I know changing the compound angle changes it's feed, but I've never seen the formula to calculate the change.

Thanks.


What happens when his precious DRO gets knocked out by a power surge???

I am sure most of us split that shabby .001 graduation on the dial into smaller bits once in a while, and do a decent job of it.....

And of course the old set the compound over trick, would confuse him even more.... An average lathe can be set to get millionths of an inch of feed.. GASP :) All with a simple Dial.....




and some math.....

macona
02-01-2008, 02:22 PM
MATH!

Hey now, watch it with those 4 letter words!

lazlo
02-01-2008, 02:52 PM
This was a case of either industrial sabotage or espionage, nobody will ever know for sure. A lab assistant stole the formula from a company in Japan who are the arch rivals of the Taiwanese in capacitor production.

That's not exactly what happened - the story is well documented: it was the Rubycon water-based electrolytic formula for their aluminum electrolytic capacitors.

Basically, a materials scientist working for the Rubycon Corporation in Japan left the company and began working for Luminous Electric in China. The defector developed a working copy of the Rubycon P-50 water-based electrolyte, used in the Rubycon ZA and ZL series aluminum electrolytic capacitors.

But then the defector’s staff members defected with a botched version of the copied Rubycon formula, and began to sell electrolyte at a ridiculously low price to several of the major electrolytic capacitor manufacturers in Taiwan, primarily Luxon Electronics, Lelon Electronics, and one other that I can't remember.

So if you have a cheap aluminum electrolytic from Luxon or Lelon, you need to check the tops of the cans to see if they're bursting, like in the picture Evan posted.

If you have a first-tier electrolytic capacitor from Sanyo, SMT, Rubycon etc, you're fine.

IOWOLF
02-01-2008, 03:21 PM
John, Have you been cruising Adrian's site again?

Looks like it to me.

DICKEYBIRD
02-01-2008, 06:34 PM
John, Have you been cruising Adrian's site again?

Looks like it to me.Nope, it's the Shop Floor Talk forum which actually has some down to earth, git 'er done kinda folks hanging around there.:) The feller that made the comment referred to probably got his decimals, goesintas and cypherin' temporarily mixed up. They're generally good folks over there too.

Oldbrock
02-06-2008, 08:25 PM
DRO? I've been machining for 60+ years and never used one. I regularly machine to .001 and hone to .0001. You techies have it too easy

Oldbrock
02-06-2008, 08:33 PM
If you set the compound to 30 degrees from in line with the cross slide when you advance the compound .010 it moves .005 toward the chuck. 30 60 90 triangle ratio is 1, 2, root3

tattoomike68
02-06-2008, 10:04 PM
I have some torch jigs that after a few test cuts I can flame bore a hole in 1/2" plate and hold +/- .015"

Iv done some big jobs where I did not have a 12"-13" micrometer so I bored the hole and made a small counterbore till the bearing race was a light press fit, backed the cut out .006" and made the cut and called it good. The race hammered in nice and tight and the job was done.

Iv done many jobs that there is no way you could measure them without milling the part in half and destroying it then using an optical comparitor.

With practice you can use a GOOD tape measure and get within .010" all day long.


brockley1 DRO? I've been machining for 60+ years and never used one. I regularly machine to .001 and hone to .0001. You techies have it too easy

Amen, I have used DRO's that had errors and use the machines dials to make sure im not off by a mile, I use a tape measure to double check. Im sure many of you guys have seen a dro jump off and start giving wrong readings. If you dont have a rule or tape to double check than shame on you. ;)