I am looking for ideas on how to couple a stepper motor shaft to a threaded rod for a CNC setup. The motor shaft is 5mm, and the threaded rod is #10 (4.8mm). Short of machining an aluminum rod with a setscrew, is there any off the shelf items for this application? I have scouted the hardware store shelves but could not come up with anything. I would appreciate any input on this. Thank you.
Wouldn't a drilled hole for a steel pin be an adequate and simple solution for a small motor?
Could you take a standard coupling for the #10 rod and drill the threads out of 1/2 of it at the 5mm size? Set screw, cotter pin(shear pin), or Locktite the motor shaft end. ______________________________ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net
A coupler with a female thread and locknut on one end and pin or setscrew on the other?
-- Randy Replogle
My wife says I'm doing my Christian duty... annoying the hell out of her. Randall Replogle 2006
--Use a helical coupling and drill holes for roll pins on both ends. Minimizes backlash and not too expensive.
Just a WAG, but if it's a really small motor and a light load, how about using a short piece of fairly thick wall rubber tubing that is a snug fit on the shaft and threaded rod along with Crazy Glue to help out?
That could give you a little bit of "universal joint" action if the shafts aren't aligned eggsackly.
HTH
Jeff
In my experience a mechanical direct connect will stress your stepper if not aligned to a micro-flea's teeth. I use U joints or those helical thingies out of McMaster Carr or Small Parts.
I think your goal is not reachable if you expect to drive anything with the #10 threaded rod. You might have a slim chance if it were a normal motor, but the acceleration characteristics of a stepper will create slippage for sure. As your goal is position tracking, slippage is unaccepable. You need another plan. Steve
Jeff has a very good suggestion with the hose. I would use one with steel braded mesh high pressure hydraulic so you get no axial twisting and use hose clamps rather than crazy glue or better yet both.
John
Any coupling in your type of application must be flexible.
Here is the universe of flexible couplers:
Universal Multi-jaw Spider Bellows Helical Offset extension
Now you just need to analyze and choose, instead of invent and speculate.
My vote would be for a Heli-cal brand helical.
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