[DonRotolo]

Hmmm. Is it possible that there is some movement in that connection? In theory, if the screw is loc-tite'd it won't back out or loosen, so the hub stays tight on the shaft. But, th the hub can expand a little (or the shaft shrink a little), allowing some loseness, you'll see it loosen up a lot more very fast.

I can't imagine the shaft getting smaller. If the hub were cracked, it would come loose, but I assume you looked for that. Foreign matter interfering with the fit?

In the past, in the non-robotics world, I had a similar problem. Never figured it out, but replacing the sprocket fixed it - maybe that will do it, especially since the other side isn't coming loose.

By the way, you guys were awesome at NJ.

Don