Re: [CAD_CAM_EDM_DRO] Does this make sense? was Re:BentNookballscrews ?????

Kim Lux wrote:

>See below.
>
>
>On Tue, 2003-08-12 at 15:13, Carlos Guillermo wrote:
>
>
>>Kim -
>>
>>So then by your wheel bearing example, if I adjust my wheel
>>bearings for 50 lbs of axial preload, then it would take an extra
>>50 lbs per wheel to roll the car?
>>
>>
>
>By my calcs, it would take 500 lbs/31 inlb per lb = 16 in lb. The ratio
>of force to torque for a 5 TPI ball screw is about 31 lbs / in lb.
>
>
>

This would make your ballscrews have a 50% power transmission efficiency,
which is actually WORSE than an Acme screw! Regular 60 degree screw threads
are supposed to be 40% efficient, I think. Acme is about 70%, ballscrews
run at 90% or better. When lightly lubed, a high-quality ballscrew (even
preloaded) is far better than your calculation above.

Jon