Question about ballscrew tpi and dia.

[timbeaulieu]

Hi all. I bought an old BP hydraulic tracer mill in surprisingly good shape and am in the process of cleaning it up and converting it to cnc for hobby use. I'm getting ready to buy some ballscrews and was wondering if anyone could tell me if there would be a difference in the amount of power needed to turn a ballscrew with a .200 tpi driven at 2:1 vs a .250 tpi driven at 2.5:1. They both would give me .0005 per step if I use stepper motors but does the angle of the thread make much difference in how much power I would need? Or am I splitting hairs? Also would the diameter make any difference? Say 1" vs 1.5" ?

Any bits of wisdom would be appreciated

[jalessi]

Hi,

The pre-load differences might make more of a impact on the force required.

Some reading info.

http://www.eu.nsk.com/downloads/ballscrews.pdf

[timbeaulieu]

Thanks for the link to the ballscrew doc. I've downloaded it and there is some good info in it. Covers most anything a newbie like me needs to know about ballscrews. Thanks again.