> > I believe he was using Archimedes screws (ie like the square-
> > cut drive screws on a lathe bed)

> > Ah, that would be Acme threads (cue the Roadrunner! :-)  

Yes, it would

"The Acme thread form uses a 29 degree pitch with flat apex and
valley. The Acme screw thread is stronger than V-profile 60 degree
threads. Wear can be compensated for with a "split nut". Typically
found where large loads or accuracy is required as in vises or the
lead screw of a lathe"

It was described to me once as an Archimedes screw, and that's
what I assumed it was called, but an Archimedes screw is more
like an auger (eg post-hole borer)

I'm sure I've seen big lead screws with zero pitch, ie take a rod
and spiral square bar around it. One project many years ago
might have needed a platform height adjustment and I enquired
about such a screw. It've had to be machined specially and
horrifically expensive, in that order

(PS, sorry, it was Gerhard doing the lab, M. Adam Davis
is Pimp My Crib)

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