Where to find old lathe chuck jaws?

[patooyee]

I have an old 12" Cushman lathe 3-jaw chuck that has worn jaws and will not grip anythign with any accuracy. It's in great condition other than that. Does anyone have a resource for getting replacement chucks for these things? The serial number is 1234B.

J. J.

[PTSchram]

Just about any of the usual suspects of machinery supply houses should be able to provide you with a suitable mounting plate and chuck. Put the mounting plate on, turn it true to your headstock, attach the chuck and away you go!

[patooyee]

So you're saying its easier to replace the chuck than to replace the jaws?

I have a back plate for the chuck. The issue is the jaws ...

J. J.

[PTSchram]

If the jaws are worn, the scroll is likely worn as well. I don't know that I'd want to put new jaws on an old chuck unless it was something special.

[patooyee]

Not anything particularly special other than that is is a nice American made larger chuck that would cost thousands to directly replace with a chuck of equal quality today. I'm not trying for accuracies within .0005 with it either. I have my 4-jaw for that. I also don't see much point in replacing a used chuck with a used chuck when I don't know that anything is wrong with the one I have other than the jaws.

J. J.

[dopeassjackson]

check ebay or craigslist

[Azzy2000]

Originally Posted by patooyee

Not anything particularly special other than that is is a nice American made larger chuck that would cost thousands to directly replace with a chuck of equal quality today. I'm not trying for accuracies within .0005 with it either. I have my 4-jaw for that. I also don't see much point in replacing a used chuck with a used chuck when I don't know that anything is wrong with the one I have other than the jaws.

J. J.

The jaws are fitted to the scroll / chuck when they are assembled. Just throwing in a different unfitted set of jaws may or may not drastically affect accuracy. Like someone else said, the scroll is probably well worn also.

Have you thought about having the jaws machined so that they are sharp again and will bite the material?

[GQtim]

If you have a working four jaw why not just use that, a 4jaw takes me 30secs generally longer to setup than a 3 jaw, holds better will allow for greater accuracy ect

[PTSchram]

Originally Posted by GQtim

If you have a working four jaw why not just use that, a 4jaw takes me 30secs generally longer to setup than a 3 jaw, holds better will allow for greater accuracy ect

Dude, you are a lot more patient than I am! I can't stand to use a four-jaw chuck and would much rather have a set-tru three jaw that I can get true and run with it.

Good quality chucks have the jaws mated very carefully to the scroll/body. It is damned near impossible to get replacement jaws to work, much less be accurate or reproducable.

[Wicked_S10]

Couple of things to check though, are you sure that the jaws are in the correct slots? The slots and jaws are numbered, and mixing them up will result in a basically unusable chuck.

How much run out are we talking about, indicated on a ground rod? Most 3 jaws are not really precision work holding devices, even when brand new. Obviously there are exceptions, very high end chucks, and set true models. I own a set true type, but have heard from various places that .003-.005 tir on a standard scroll chuck is not unusual at all, especailly in worn stuff.

You could do a google search on grinding your chuck jaws, there are lots of pages with setups and how to's. Another option would be to convert the jaws to a soft face. I have seen it done where the jaws are milled down, then small aluminum jaws are made that bolt in place. You then can bore the soft jaws easily, and make different jaws for different types of jobs. The biggest problem with grinding the jaws, or even boring soft jaws, is, if the scroll, or body of the chuck is fubar enough, then the jaws will only be truly concentric at the diameter they were ground at.

Later,
Jason

[Wicked_S10]

Oh, another thought, you can also find some relatively simple DIY methods to turn most chucks w/ a seperate backplate into a home made type set true.

[1TON73K5]

Give this place a try. http://www.calaerosupply.com/They have been in bussiness for years and have bought out old machine shops going out of bussiness and bought from auction's from machine shops. They have a MASSIVE warehouse that has more stuff then you can even imagine. They have stuff they have forgotton about for years. I was looking for an 8" 3 jaw chuck for my lathe. One of the guys that works there used to work at the machine shop I used to work at. He took me in the back where they keep chucks, there were pallets and pallets of old chucks of every size imaginable. I searched for about 45 mins and found a chuck in great shape. Paid 55 bucks for it. Good luck.

[jamscal]

I have an old 6" 3 jaw with a screwed up scroll. It will make a good welding positioner one day.

If it is your jaws and not scroll I've seen people rig up a dremel with a grinding wheel on the toolpost. That could get you close enough for 3-jaw work.

You need to test for runout at gripping different diameters of stock. If it's way out at 1" but close at 3" (or vice-versa)you have scroll problems.

-James

[GQtim]

Originally Posted by PTSchram

Dude, you are a lot more patient than I am! I can't stand to use a four-jaw chuck and would much rather have a set-tru three jaw that I can get true and run with it.

Good quality chucks have the jaws mated very carefully to the scroll/body. It is damned near impossible to get replacement jaws to work, much less be accurate or reproducable.

I do it for a living! we have a 3 jaw for that 5 sec job where you need a chamfer or something silly like that but for the rest its 4jaws on all lathes