Something is wrong with your drawbar, spindle, or collet. 1000 pounds is almost 2X what you require for an X2. If you're getting pullout, that 1000 pounds is NOT being transmitted properly to the collet. Remove the Bellevilles, and replace them with flat washers or a hard spacer. Can you then tighten the drawbar enough to NOT get pullout? I'm guessing you'll find you can't, which means something is preventing the collet from pulling far enough up into the spindle to close fully.

Regards,
Ray L.