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daved20319
03-03-2012, 12:29 PM
I'm currently working with some 1/8" O1 tool steel rod, making parts for a couple of project air guns. My question is, how do you guys hold stuff this small? The smallest my chuck will hold is about 1/4" diameter, I've had to resort to using my mini mill as a vertical lathe. Is my only option a collet chuck, or is there another way? And if a collet chuck is the only viable option, what's a decent one that won't break the bank? Or maybe a better question, which one's should I avoid like the plague? BTW, if it matters, the machine is an older 12x24 belt drive Grizzly with a threaded spindle, 2.25"x8. Thanks, gents.

Dave

Black_Moons
03-03-2012, 12:34 PM
I use 5C collets held in a square collet block held in my 4 jaw chuck. Its a little annoying, but it gets the job done nicely.

JoeCB
03-03-2012, 12:36 PM
how about a split bushing? 1/8 ID X 5/16 OD. If you are only doing one or two pieces , a shotr length of soft copper tubing will crush in the chuck jaws and hold the stock.

Joe B

Black_Moons
03-03-2012, 01:07 PM
how about a split bushing? 1/8 ID X 5/16 OD. If you are only doing one or two pieces , a shotr length of soft copper tubing will crush in the chuck jaws and hold the stock.

Joe B

They must use really thick copper tube where you live!

dockrat
03-03-2012, 01:09 PM
I use 5C collets held in a square collet block held in my 4 jaw chuck. Its a little annoying, but it gets the job done nicely.

I do the same except I use a hex block in my 3 jaw

Mcgyver
03-03-2012, 01:31 PM
all good ideas.

another is take a a short length of round stock, say 5/8 or so. Cross drill and tap for a set screw. Chuck in the three jaw, spot drill, drill and ream 1/8 - do a pass with a miny boring bar before reaming if you want guaranteed perfect alignment of the hole. This is an easy way to hold the 1/8 stock....and so long as you don't remove it will be quite concentric. Mark the location of a jaw on it and you should even be able to repeat fairly well

dian
03-03-2012, 02:01 PM
hm, so what acuracy is yout tailstock set to?

i would put a small independent 4 jaw chuck into the big chuck.

Mcgyver
03-03-2012, 02:07 PM
hm, so what acuracy is yout tailstock set to?


who's tailstock and why?

Martin0001
03-03-2012, 02:12 PM
I'm currently working with some 1/8" O1 tool steel rod, making parts for a couple of project air guns. My question is, how do you guys hold stuff this small? The smallest my chuck will hold is about 1/4" diameter, I've had to resort to using my mini mill as a vertical lathe.
Dave
Buy used ML7 of Myford (England).
Spares still available of manufacturer and plenty on e-bay too.
I have one and I am *extremely* pleased with it.
Tuned to 0.0005 in/ft accuracy... for a 43 yo girl.
She got general overhaul 8 years ago, when was bought.
Will serve next 80 years, I believe.
Modern crap stand no chance to compete whatsoever...

dian
03-03-2012, 02:21 PM
"spot drill, drill and ream 1/8 - do a pass with a miny boring bar before reaming if you want guaranteed perfect alignment of the hole."

well it dont know (iv had a couple of chiloms already), but dont you do this from the taistock?

dian
03-03-2012, 02:28 PM
"guaranteed perfect alignment of the hole."

so if the tailstock is not perfect, youll get a conical hole and the set screw will introduce an error of 0.01 mm (at least).

but then again, iv had two chilloms already, so forgive me for thinking aloud.

Mcgyver
03-03-2012, 02:58 PM
"spot drill, drill and ream 1/8 - do a pass with a miny boring bar before reaming if you want guaranteed perfect alignment of the hole."

well it dont know (iv had a couple of chiloms already), but dont you do this from the taistock?

no problem thinking out loud...in my experience with the work rotating a spot drill will get pulled into cutting a very concentric cone...even if the tailstock is off (a bit). use a very soft touch when starting and let the bit get pulled to the centre of the work. If the tails stock so so far out this wont work, slew the compound over and single point the cone

Once the hole is spotted, the tailstock being out will have minimal to an unmeasurable affect on the drill and reamer's path, again assuming its not out an extreme amount

The part that guarantees a true bore is to follow up drilling with a single point boring tool before reaming. I know its small hole but not so small you can't use or get a boring tool that'll work. The challenge then is that this 1/8 hole might be too long to easy to bore its length....so what you do is single point bore, very carefully, a short length at exactly 1/8. The sides of the reamer will then follow this and cut a very true hole, regardless of the tailstock being out.....its pulled true by the single point bore. Reamers are the length the are to allow a bit flex.....ever turned the drill press on and seen a reamer with a a bit of wobble to it?...but it goes away and doesn't affect the bore once you start reaming? same thing here.

All implies a matter of reasonableness.....if its 1/2" of course its not going to work, but a tailstock being out bit does material effect the accuracy of holes drilled and reamed from it using the above techniques

The OP may not even need concentricity with the chucked part, then its mostly moot....but if he does this will work very well.

Duffy
03-03-2012, 05:41 PM
What chuck system wont break the bank?
I think the Grizzly has an MT-4 taper. If so, an adapter MT-4 to MT-3 and an MT-3 collet should work. CDCO Tools have an inexpensive set, and individual units are about $12.00 each.

BudB
03-03-2012, 08:47 PM
Split Bushings............reusable, simple, cheap

Clevelander
03-03-2012, 08:59 PM
You mentioned you wanted to turn this material down but you didn't mention the degree of accuracy you needed in your final diameter.

This little bit of wisdom was given to me by Bill Huxhold (I bow to the east for my machining god;) ) If you need an accurate small diameter you may need to start with a larger diameter rod to prevent deflection and turn the diameter you need in a single pass with a slower feed. The reason is that the larger diameter provides it's own support while you are making the cut.

Thanks Bill.

If you'd seen my high school pin punch you'd know why I'm saying that. But I got the tempering just right.:D

Jaakko Fagerlund
03-03-2012, 09:24 PM
For small stuff holding I usually use either collets or a drill chuck. I made a small adapter for the drill chuck so that it fits in to a collet and has a hole through it, so I can hold longer rods in it. The drill chuck has a very good repeatability and accuracy, I think it was spec'd at 0.015 mm runout.

Peter.
03-04-2012, 03:23 AM
I have an ER25 collet chuck on a morse taper with a drawbar that I can pull into my heatstock taper. Also fits my dividing head.

dian
03-04-2012, 05:34 AM
jaakko, what drill chuck is that? the last one i checked had a runnout o 0.15 mm.

Lew Hartswick
03-04-2012, 10:04 AM
This little bit of wisdom was given to me by Bill Huxhold (I bow to the east for my machining god;) ) If you need an accurate small diameter you may need to start with a larger diameter rod to prevent deflection and turn the diameter you need in a single pass with a slower feed. The reason is that the larger diameter provides it's own support while you are making the cut.
This technique works very well for tapers also. I had a need to make
replacement "shear pins" for our lathes, brass about 1-1/2 long by
about 3/16 (I forget the taper pin number) but was told by a friend
who has been into small models for ages to start with a larger diameter
and take it all at once, like you said. WORKS like a dream. :-)
...Lew...

Jaakko Fagerlund
03-04-2012, 02:19 PM
jaakko, what drill chuck is that? the last one i checked had a runnout o 0.15 mm.
They are called "notcheaps", usually spec'ed with a nice DIN standard for runout and some of them use hydraulics to lock the drill bit.

If your drill chuck has 0.15 mm runout, how are you going to drill anything reliably with it? I would toss that out to scrap bin immediately.

mikey553
03-04-2012, 07:46 PM
Dave,

What chuck diameter are you using? My 12 x 36 Grizzly came with 6" 3-jaw chuck, capable of holding .090" with .001" runout. Maybe it is time for you to look for another chuck...

In case I need to hold even smaller diameters I mounted a 2" 3-jaw chuck from Horrible Freight on a cylindrical arbor. The arbor goes in the big chuck. This 2" chuck is very inexpensive and is not so good except for special needs. I have ground the jaws, so the runout now is more or less acceptable. This chuck can hold less than .040" diameter. The arbor has a hole through of about 1/8" for a long stock.

dian
03-05-2012, 03:21 PM
jaakko, a regular drill chuck will have a runout of 0.3 mm.

so, first i bought a bison class 1, advertised at 0.07 mm. it had 0.15. too much trouble sending it back. next i got a röhm spiro (was on sale, something like 150 $), advertised at 0.05 mm. it has 0.15 and im sending it back. there is an albrecht chuck advertised at 0.020-0.045, but im not buying it at 250 $, because i dont believe it.

if you got a chuck with 0.015 mm runout im bidding 200 bucks for it.

i measure like this.

http://i973.photobucket.com/albums/ae218/romandian/flansch001.jpg

Mcgyver
03-05-2012, 04:33 PM
dian, a lot of the detail there is in shadow - what's going on at the front of the chuck - next to three jaw, hows the outboard end of the large taper held and how are you testing - ie rotating the chuck between centres....or rotating the 3 jaw

Jaakko Fagerlund
03-05-2012, 05:00 PM
dian, attach that drill chuck to your milling machine or drill, wherever that taper fits, then put a ground pin in it and measure the runout.

If you have a good drill chuck, you can use it to hold a chucking reamer and get perfect results.

dian
03-06-2012, 03:34 AM
i have yet to find a ground pin (or anything else) that is perfectly round. try rotating the ground pin in the chuck and you will get a different amount of runout.

somehow i thought this was the standart way of doing in: the drill chuck is on a trued pin and the lathe chuck is rotated.

i still would be interested to know, what drill chuck gives you 0.015 mm runout.

Jaakko Fagerlund
03-06-2012, 04:11 AM
i have yet to find a ground pin (or anything else) that is perfectly round. try rotating the ground pin in the chuck and you will get a different amount of runout.

somehow i thought this was the standart way of doing in: the drill chuck is on a trued pin and the lathe chuck is rotated.

i still would be interested to know, what drill chuck gives you 0.015 mm runout.
You can easily find ground pins (like dowel pins) that are more than round enough for these tests.

If you get different runout when changing the pin position, then your chuck is not in good condition or the pin is not straight/round or there is junk between the pin and the jaws.

What you mean by a trued pin?

I'll show you a photo once I get off from work later today of the drill chucks I'm talking about. And yes, they do cost 200-300 EUR per chuck, but worth every cent.

mike4
03-06-2012, 04:56 AM
dian, attach that drill chuck to your milling machine or drill, wherever that taper fits, then put a ground pin in it and measure the runout.

If you have a good drill chuck, you can use it to hold a chucking reamer and get perfect results.
I second putting it in a mill and measuring the runout.
Michael

oldtiffie
03-06-2012, 06:40 AM
Here is the OP:


I'm currently working with some 1/8" O1 tool steel rod, making parts for a couple of project air guns. My question is, how do you guys hold stuff this small? The smallest my chuck will hold is about 1/4" diameter, I've had to resort to using my mini mill as a vertical lathe. Is my only option a collet chuck, or is there another way? And if a collet chuck is the only viable option, what's a decent one that won't break the bank? Or maybe a better question, which one's should I avoid like the plague? BTW, if it matters, the machine is an older 12x24 belt drive Grizzly with a threaded spindle, 2.25"x8. Thanks, gents.

Dave

In my lathe for that sort of work I use ER-32 collets which each have a gripping range of 1mm (~0.04") from 2mm (~.08") to 20mm (~0.80") with 18 collets in 1mm steps and each has a griping range of 1mm (~0.04").

1/8" = 0.125" x 25.4 = 3.175mm which will fit in the 3-4mm collet.

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith06.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith03.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith01-1.jpg

Mcgyver
03-06-2012, 08:19 AM
i have yet to find a ground pin (or anything else) that is perfectly round. try rotating the ground pin in the chuck and you will get a different amount of runout.

somehow i thought this was the standard way of doing in: the drill chuck is on a trued pin and the lathe chuck is rotated.

i still would be interested to know, what drill chuck gives you 0.015 mm runout.

So you've turned the spigot in situ then mounted the chuck on it? Not a bad a bad way to come at it as it somewhat isolates the chuck from arbor.

I've done as Jakko describes with the pin, if the results are good all is well....but if not there is a weakness with this in that in does not isolate the error to chuck or arbor. I remember once having a Jacobs chuck that I thought was terrible, replaced the crappo arbor and bingo it was perfect.

the testing process is about isolating where the error is. First indicate the inside of your mill or drill's spindle, whatever the taper mount goes into. Should be fine, but we want to be methodical to eliminate error.

Then remove the chuck from the arbor and mount the arbor in the mill (after carefully cleaning and inspecting the tapers). indicate the arbor.

If its good, mount the chuck on the arbor, again carefully inspecting and cleaning the tapers, re-attach to the arbor. You don't need a ground pin, (a pin is great if you have one but don't let that stop you) you just need something round. Turn a short piece and strive for the best finish you can get, it'll be as round as your lathe's bearings.

mount it in the chuck and indicate. being aware to look for dirt, burrs, warts and pimples on the tapers as the obvious cause, this series will tell you where the problem is

photomankc
03-06-2012, 10:48 AM
In my lathe for that sort of work I use ER-32 collets which each have a gripping range of 1mm (~0.04") from 2mm (~.08") to 20mm (~0.80") with 18 collets in 1mm steps and each has a griping range of 1mm (~0.04").

1/8" = 0.125" x 25.4 = 3.175mm which will fit in the 3-4mm collet.

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith06.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith03.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith01-1.jpg

Love it! how is that Collet chuck held in there?

Jaakko Fagerlund
03-06-2012, 03:11 PM
i still would be interested to know, what drill chuck gives you 0.015 mm runout.
http://i4.aijaa.com/t/00131/9717996.t.jpg (http://aijaa.com/001319717996)

That is a used drill chuck, but only shows 0.02 mm TIR.

Now, if your drill chuck shows 0.30 mm runout or even half of that, it is not good for drilling anything accurately and probable reason is that it is too cheap.

The one shown in the photo is marked WTE, but can't remember the exact product code.

Black_Moons
03-06-2012, 03:28 PM
Eh? grab a glacern. Mines good to at least 0.001"/0.025mm. I would say its likey better but thats as good as I trust the chunk of steel I chucked to be round/straight.

oldtiffie
03-06-2012, 06:33 PM
Here is the OP:


Originally Posted by daved20319

I'm currently working with some 1/8" O1 tool steel rod, making parts for a couple of project air guns. My question is, how do you guys hold stuff this small? The smallest my chuck will hold is about 1/4" diameter, I've had to resort to using my mini mill as a vertical lathe. Is my only option a collet chuck, or is there another way? And if a collet chuck is the only viable option, what's a decent one that won't break the bank? Or maybe a better question, which one's should I avoid like the plague? BTW, if it matters, the machine is an older 12x24 belt drive Grizzly with a threaded spindle, 2.25"x8. Thanks, gents.

Dave



In my lathe for that sort of work I use ER-32 collets which each have a gripping range of 1mm (~0.04") from 2mm (~.08") to 20mm (~0.80") with 18 collets in 1mm steps and each has a griping range of 1mm (~0.04").

1/8" = 0.125" x 25.4 = 3.175mm which will fit in the 3-4mm collet.

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith06.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith03.jpg

http://i200.photobucket.com/albums/aa294/oldtiffie/Lathe_misc/AirSmith01-1.jpg


Love it! how is that Collet chuck held in there?

It seems a bit confusing I suppose but that ER-32 chuck has an MT3 taper to fit my mills.

The ER-32 adaptor has all the ER-32 requirements as regards taper, nut etc. and operates in the lathe the same as the MT3 adaptor works in the mills.

The lathe ER-32 adaptor is a "bolt on" fitting to the lathe flange the same as my 3 and 4-jaw chucks etc. do.

It has a small - about 0.002" as I recall - clearance from the lathe flange spigot that aloows me to use itas a "set-true" as I put the adaptor onto the lathe flange and just "nip" it, put the correct collet in and the job in the collet, put an indicator on the job, turn the lathe by hand and "tap" the job "true" with a bit of phosfor bronze (a "dolly" and "dead blow" hammer), finally tighten the adaptor to the lathe flange, re-check and if OK I am ready to go. I have eliminated most error.

It works very well.

The main advantage of collets over 3 and 4-jaw chucks is that the collets have very little if any "bell-mouthing" and so the job is gripped right up to the front/nose of the collet.

I bought the collet adaptor in the USA from either CDCO tools or Little Machine Shop (forget which).

I bought the collet and MT3 adaptor set here in Australia.

I can also bolt that lathe adaptor to my mill table or my 6" rotary table and tilting angle plate etc.

http://i200.photobucket.com/albums/aa294/oldtiffie/HF-45%20Mill%20misc/HF45-4-1.jpg

A very handy bit of kit.

dian
03-08-2012, 04:13 AM
mcgyver, thanks for that. i measured several of my chucks as you say, the result being, that the runout was always larger than when using the method i showed. you even take some slop out of the bearings when measuring like that.

jaakko, black: measure the runnout 150 mm from the chuck (as specified by röhm), i wonder what you come up with. i have röhm, albrecht, jakobs, bison chucks among others and its hard to believe that everybody has 0.02 mm runout chucks, while mine have between 0.30 ans 0.15 mm. the last röhm i got should have 0.05, thats why i sent it back. i wonder what the replacement will be like.

the wte of course are high end chucks, if you have the precision one for 400 euros you are lucky.

vpt
03-08-2012, 08:04 AM
Smaller work = smaller lathe.

http://img6.imageshack.us/img6/4887/dieseljets008.jpg

daved20319
03-08-2012, 10:26 AM
Some interesting information has been posted on this thread, albeit not all particularly helpful to me :-). I've decided to try a couple of different ideas for now. I've got a set of 5C collets and a pair of collet blocks on order, as well as a set of ER type collets and an MT 3 adapter, all from CDCO. I suspect one or the other will do what I want, if not both, and if the quality isn't what it could/should be, I'm not out that much. Will post something akin to a review when I get them and get a chance to try them out. Later.

Dave