Hi. I'm trying to squeeze out as much backlash from the SFU1605 ball screws as I possibly can from my new build. I've already replaced the bearings in the support bracket with angular contact bearing.

I have the Z-Axis screw apart and have measured the balls using a micrometer. All of them measure between 0.12530" and 0.12535".... So gonna call the average 0.12532".

I was thinking about 5 ten thousandths (.0005") seemed reasonable. That would put the new baseline @ 0.12582". Of course actual size will depend on what is commercially available.

Is there a rule of thumb or some general guideline on how much oversize one should go.. at least as a starting point?

Here are a couple of pics of the machine I'm working on.