Posted by bills on November 09, 2009 at 11:08:30:
In Reply to: Re: BC 16-16 Issue with involute spline cutting posted by Jesse McClain on November 09, 2009 at 00:09:34:
I confess I never had a 16-16, but I've been around a few.
Here is the adjustment to index worm endplay on a No. 12. Endplay is the ability of the worm to move up and down in the housing. Don't confuse this with backlash! On top of the index worm shaft is a tubular cover that you can unscrew and remove (it may be removed already!). Below the cover are two jam nuts locked together. Loosen the top one and use the bottom one to adjust out (most of) the endplay in the worm. You will want to torque the work spindle to move the worm against the endplay (put a gear on the work spindle and an indicator on a tooth to see the motion).
Backlash between the index worm and gear is adjusted by loosening the whole housing. Take the large round cover off, rotate the worm gear until the screw heads are exposed, then loosen them slightly - don't remove them! There are two small opposing screws between the machine and housing - loosen one and snug up the other to shift the housing slightly. These two screws are for adjustment only so don't over tighten them. Using the two screws shift the housing (with worm) toward the worm gear very slightly to take out backlash. Tighten and recheck.
In general, taking out endplay and backlash is a tradeoff between increasing frictional heat (and chance of seizing up) and leaving just a small amt of play. Seems like when things are adjusted right the housing will get warm but not too hot to touch.
16-16's were designed with ball and roller bearings, so you may need to replace bearings - don't know if there is actually adjustment or not.
Hope someone with real 16-16 experience jumps in here. I'm in over my head, guys :o)