View Full Version : Making your own lathe chuck

02-27-2002, 09:20 PM
If one wants to make a self centering 3 jaw chuck, not that I would ever attempt it, how do you machine the plate with the spiral notches that drive the jaws without using a CNC? Equally difficult are the jaws, which must have matching curvature which follow the spiralling pattern. I really get a kick out of figuring out how I would machine things if I really had to.


02-28-2002, 12:53 AM
Each jaw is also different. I think they made mechanical marvels (such as differential indexers tied to table feed to mill flutes in drills). It may be witchcraft - who knows. All I know is it is much easier to just buy a good chuck than to make a really bad chuck. Four Jaw independents are quite easy to make.

Did you know that there are Four Jaw chucks that also have a scroll? The are really neat chucks, but the smallest and most economical I have seen is a 8" Bison ($1400 - Forged Steel)


02-28-2002, 07:49 AM
Well, I know it's possible...I know that the "Dad" of "Rollie's dad's lathe alignment technique" ( http://people.ne.mediaone.net/wasser/NEMES/RDMLatheAlignment.html ) once made a set of replacement scroll chuck jaws without benefit of CNC. He's quite a guy.... At any rate, the jaws are basically the same problem as the scroll, so if you can do one you can do the other.

I'd guess it could be done with power cross feed on a lathe. You'd have to keep the power feed engaged all the time and reverse the motor to back up, as engagement is by the clutch, not the halfnuts.

02-28-2002, 11:45 PM
suspect they were done w/ dividing head geared to table traversing gearing on uuniversal horiz. mill
best wishes

03-01-2002, 05:54 AM
Yes -- that's likely the "real" way to do it.

kap pullen
03-01-2002, 08:57 AM
I think it's likely they have a thread mill(like the old Cri Dan machines) set up for cutting the spirial on the face.
The Cri Dan machine could cut 3" - 2 tpi acme threads x 6" long in about two minutes.
It was a fully automatic lathe operated by cams mad dogs.
Once it started it's cycle you kept the heck away, because the slide really flew.
You'll be forever milling a spirial like that.