Ball Screw Balls

Hi All,

I have a ground ball screw and nut combo. It is a .2in pitch screw
and has a nut with two races for the balls, each holds about 100 1/8
in balls. The problem is that when I fill one with balls, it runs
very smoothly, with very little backlash. When I try and fill the
second race, the nut binds up and becomes hard to turn.

Is there a place to get balls of slightly smaller diameter, say
.1245in? Or do I have a defective/mismatched nut/screw?

Thanks for any advise.

Dustin