Jinx wrote:
> I'd tried Archimedes screws for a project a long time ago and found
> friction a problem, although they're fine for something horizontal like
> a lathe bed

Slight mixup in terminology there -- an "Archimedes screw" is actually a
device for lifting liquids. I think you mean "Acme screw", which is
typically the leadscrew device used on flatbed applications like lathes
and mills. A "ball screw" mechanism helps address the friction and wear
issues, but is considerably more complex and costly.

-- Dave Tweed
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