auto-balancing bench grinder arbors

[mattthemuppet]

no worries at all, I didn't take it like that. I've heard other people say Norton stones are often out of balance, I must have either gotten lucky or it's been worn down enough to smooth it out.

had a play last night, recutting the groove on the wire wheel side to fit 5/32 balls from an old bike headset bearing. After playing around with ball number, between 10 and 15 (1/4 and 1/3 full) seemed to work the best, although it didn't completely remove the vibrations. Probably about 2/3 less vibration with the balls in than not, compared with about 1/3 reduction with the 3/32 balls. 3/16in or even 1/4in balls would probably get that last 1/3 but I don't have any 3/16 balls and I don't have enough material in the arbor to safely cut the groove 1/4in deep. Good enough for me and now I can get onto the next project!



edit - for 8in stones, I'd make the arbor with a larger diameter (mine are 2 or 2 1/2in, can't remember) and start with 1/4in balls. It's a fairly simple project, the machining didn't take long at all.