Chinese Ballscrew nut play

[Fancy]

The sizes i found were 3.12, 3.14mm and 3.16mm and the ones that were packed in the screw were 3.10mm. i tried each by them selves @ 3.12mm there was wiggling so i increased the ball size the wiggle decreased but the at some points along the screw it got harder to turn then i tried alternating with 3.10 but no luck 3.12 & 3.10 wiggles & 3.14,3.16 with 3.10 wiggles and get harder to rotate at some points along the screw.

[m_c]

It sounds like you've got cheap rolled ballscrews, which as you've discovered, are not great for accuracy.

The only thing you could do (other than buy a new screw), is put the bigger balls in, and hope they wear/burnish in the tight spots on the screw, but you do risk damaging things if thing are too tight. If you do try this approach, I'd make sure things are kept very lubricated to help flush any debris out, until you are happy things have bedded in nicely.