Herlp with Sherline Stepper Motor Mounts?

Hi,
I installed the sherline motor mounts on by lathe, and the crossfeed
seems to become loose. I tightened the inner SHCS as tightly as
possible against the nut, but it always comes loose after jogging
the machine a couple of times.

My cross feed is tight; it seems to bind a bit. I loosened the
plastic gib as much as possible, but its still tight. Never had
this problem with my handcranks.

Has anyone had the same problem?

Thanks,
Mark