Started working on the X axis for real today and got tripped up by new problems.

Discovered that the ball-nut mount doesn't have a set-screw, so I get to drill/tap my own.

While threading the ball-screw housing onto the screw I got surprised by a small number of balls coming out the rear of the housing. I searched and found 11 total, I don't know if there were more that I couldn't find. The preload sets ok and the ball seems to turn, so I'm not sure how concerned I should be.