Ballscrew Thickness!

[irving2008]

Please don't resurrect ancient threads, start a new one.

Anyway, to answer your question, there is no easy 'optimal' as it all depends. However the easy option is to go near like for like and use 30mm dia 5mm pitch.

However that screw is rarely going to be turning at more than a few rpm (<1 for metric fine threading, <100 for a finishing pass and maybe 1000 for a rapid traverse) and despite it's 11kg weight only needs <1Nm to accelerate it to cutting speed in under 1mm of traverse. So a servo is massive overkill and gearing it down while avoiding backlash is going to be tricky.