View Full Version : First Longworth chuck. need to make one more

Alex Elias
02-05-2008, 2:06 AM
Well I got inspired and made me one. It operates wonderfully but it did not perform. So here is the dilemma and the question.
I used 3/4" ply 15 1/2 in diameter for both discs and everything worked out great aside form the ply warping ever so slightly. Needless to say it renders the chuck worthless since it wobbles about 1/16". I figured, that must be the reason so I'm ready for round 2.
What is the preferred material to make it? I figure MDF but I like to know what your opinions are. Would you use 3/4 for both discs? I don't know where I could get MDF thinner than 3/4. Would lowes or HD sell less than a 4x8 piece of MDF?
Thanks for the info.

Ken Massingale
02-05-2008, 8:34 AM
The HD's around here have 1/2" MDF.

john frank
02-05-2008, 9:31 AM
MDF is available in different thicknesses. Its common material at most large cabinet shops. Try one near you, they probably have scraps.

Kevin McPeek
02-05-2008, 9:44 AM
I used birch ply to make a donut chuck and I was surprised on how much I had to face it before it would run true. I have heard mixed advice about using mdf for chucks but I know it has been done by many people. You can get it at the big box stores in 3/4, 1/2, and 1/4 in 2'x4' sheets as well as the normal 4'x8'.
If you do go by the cabinet shop looking for scraps see if they have any Corian scraps while you're there.

Jerry Allen
02-05-2008, 9:58 AM
Most HDs and Lowes I go to have cut 2'x4' panels but not always every thickness, but you might ask for them to cut up what you want.
I see 1/2" often, and you could use 1/4 tempered hardboard for the front.
I use 3/8" and 1/4" baltic birch and it works fine. It's very stiff when tightened down.
One of the things that may make it wobble is the mounting method. A hair at the headstock center is magnified at the circumference. Use screws and shim even if you think it's flat and square.

Mike Golka
02-05-2008, 10:40 AM
I made mine out of 3/8" MDF and it is holding up well. It is very stable and after about 6 mounths of use still hasn't given me any trouble.


Bernie Weishapl
02-05-2008, 12:05 PM
Mine is made from 3/4" MDF for the back plate and 1/2" for the front. Works slick.

Alex Elias
02-05-2008, 1:21 PM
Thanks for the info. I took it appart again last night and check the warp. It is only on one of the plates (the one that drives) before I make one more I'll try to pass the one I have throught the drum sander and see what happens, or just scrape the face of the disc. I think trueing the one I have sould be faster.
I'll post once I done.