Ok I have my Roton Ballnuts in now and removed all the balls from one. They are for .631x.200 Ballscrews. The nut contained 67 balls and I was figuring on 1 or 2 sizes of balls if they used spacer balls. Here is what I measured with my micrometer.
Quanity mm size inch size
12 3.09mm .121653"
23 3.10mm .122047"
18 3.11mm .122440"
5 3.12mm .122834"
7 3.13mm .123228"
2 3.14mm .123622"
Now in giving that the total difference between the largest and smallest balls are .001969" which would be the best sizes to look for to remove as much backlash as possible from a rolled ballscrew? Thanks in advance.