Tool & Cutter grinder options...

The closest I got was to use a small copper coin placed against the first tooth of the jaws (i.e., not the gripping surface but just beyond it) and lightly tighten the jaws onto that. This configuration leaves the whole length free for grinding. Unfortunately, although it tensions the jaws correctly, with it being right at the back of the jaws it also causes the jaws to take up all clearances in one direction only - an unnatural bias, and if the slots are slightly worn you still end up with a slight bell-mouth.

Chris

Maybe its time for a re-think on chuck design?

If the scroll thread was trapezoidal instead of being square, the jaw would be driven away from the chuck body when it was tightened and take up any slop on the slots.

It might work.

Ian P

Chris

The video is clear enough to show what you are doing OK, but grinding the jaws by referencing off the OD of the jaw is, as you discovered, not likely to be particularly accurate.

I suppose if you gripped a bar normally, then used a toolpost grinder to take off the very (OD) tips off the jaws you would create reference points that would relate to each particular jaw. Then you method might work.

Ian P

Hello all

You need one of these to load the jaws in the proper direction against the scroll.

I used a stone just a little smaller in diameter than the jaw gripping diameter

Can't remember what I used as the grinding spindle, could have been the

spindle from my Taylor Hobson engraver and a lash-up drive.

I think the original idea was from "Duplex" in ME.

Jim

Jim - great idea, I hadn't thought of that one

Ian, the reference point(s) were the first step not the tips of the jaws, those must surely be concentric otherwise these outside jaws couldn't work at all.

Chris

Chris

Yes I saw they were referenced on the step, what I was suggesting was to tickle up the step to create new references with the jaws tensioned.

Ian P