Rotating Ballnut - design ideas

[Jonathan]

You'll have far bigger sources of play than 11 microns in a bearing!

I was thinking it's best to eliminate as much play as I can. In that case it's either the design #13 or #7. The latter, with one bearing, is easier to machine and cheaper, but less stable and bigger pulley. I'm worried about getting the centre height in the design with two bearings accurate.

Whether you use two ball nuts or nut, will depend entirely on how much play you're willing to allow (or money you're wanting to spend!), and there will also be an increase in friction using two preloaded ballnuts.

I've worked out that linearmotionbearings only charges £18 per RM2510 ballnut (and about £31 per meter of the screw), so it's not much more to have a second nut. Friction is a good point since the whole idea of this is to make the machine run faster.