Posted by BillS on January 31, 2010 at 13:48:13:
In Reply to: problems with Barber Colman #12 posted by Jim Pollock on January 30, 2010 at 22:26:05:
Hi Jim,
I know you said there is no more than 0.001 backlash in the work spindle, but you need to look at the endplay
of the worm that drives the large index worm gear. This worm has an adjustment for endplay, and it sounds to me like there
is too much endplay. It should be nearly "0" with the gear and worm at operating temp.
Another clue of too much endplay is that the worm housing runs cool. The housing should get hot after 15-20 minutes running.
Endplay is not easily seen unless you torque the work spindle really good 'n hard. I suspect the .001 you saw was just the backlash between worm and wormgear.
The cutter has plenty of force to make the worm "jump" inside its cradle especially since the running friction is much less than static friction; i.e., with machine at a standstill, you must make the worm move against static friction in order to measure its endplay motion.
I don't think the 60T gear wobble is causing your problem just based on my experience. Opinions anyone?