Thread: Lathe 3-jaw Chuck Wear

I am using the wood router with grinding wheel to do both "internal" and "external" and it seems to work for me...

Originally Posted by lamestllama

Can you give a description of the setup? I would like to understand what you use as a datum?

I finally located the fixture that I used to hold the jaws for grinding, it has pins that use the slot in the jaw as one datum and another pin that registers against the step jaw.

The process involved to achieve good results is time consuming and begins with disassembling the chuck, cleaning, removing any burrs or bruising,lubricating and reassembly/mounting.Chuck Jaw Grinding Fixture.JPGFixture and Clamps.JPGFixture with 5 inch jaw..JPGFixture with 8 inch jaw.JPG

Following is a photo of the subject chuck jaw.

3-jaw tip compr.JPG

I have 4 chucks, all with tip radii approx 25 mm:
- subject 3-jaw tip is 7 mm wide and shows evidence of previous grinding.
- new 3-jaw tips 4.5 mm,
- old 4-jaw tips 3.5,
- new 4-jaw tips 4.5 mm.

So, I plan to surface grind the subject tips down to about 4 mm or so before the lathe grind.
I wonder if some of the problem is the tips are now through the case hardening layer ?

Welcome comments on the situation with chuck jaw hardening.

Techo1, interesting to see the description of grinding on a T&CG.
My approach would have been similar to that described by caskwarrior, but using an angle plate.

Thanks jackaroo for the photos, my clamp ring will be similar.

John