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best molded thread form for low friction

best molded thread form for low friction

best molded thread form for low friction

I am looking to position something with molded threads. it's small, low load. I'd like minimum friction.
Since I am molding the threads, I have some freedom. backlash is not a big issue.

I am thinking buttress- type threads will give less friction than acme or others. it will be a very steep, 3 start thread, so the goal is back-drivability, and low stroke. regardless, I will likely make them "stub" threads.

thanks for your thoughts.

RE: best molded thread form for low friction

I agree. My guess is that a 90 degree flank angle, ie a square thread, with a large amount of clearance, will have the lowest friction. You might need to get clever and actually go for a negative angle, so that under load the form deflects to give constant surface pressure and no wedging.


Greg Locock

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RE: best molded thread form for low friction

A bigger consideration is the parting line.
Consider using a double-D shape, so the parting line mismatch doesn't get near a sliding surface.

Mike Halloran
Pembroke Pines, FL, USA

RE: best molded thread form for low friction

The double-D recommendstion most usefully applies to male tbreads.

For female threads, interrupted threads may be useful, but flash removal can be a problem.
It may be useful to mold around a polished male threaded core and spin it out.

Mike Halloran
Pembroke Pines, FL, USA

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