I have a Nema23 that has a 1.8 degree stepping resolution. The motor has a GT2 pulley attached on the rotating element. This GT2 pulley is coupled with another pulley, using a belt, which is directly around the shaft of a lead screw.

I'd like to increase my stepping resolution, I already use micro-stepping, so I was thinking of using a 60 tooth pulley on my lead screw and a 20 tooth pulley on the stepper. Such that a step from my motor would result in less rotation of the lead screw. But what I am curious about is how will this affect the torque experienced by the motor? Will I be able to lift the same load, or maybe even more? Are there any drawbacks to such a modification?

  • $\begingroup$ PS- you may know this, but can't hurt mentioning - while you can readily get a 32x-128x microstepping driver now, and it will help extend the range of speed, as well improve smoothness at low speed, by creating a good sine-wave voltage or current profile, it probably won't give you nearly that multiple of an improvement in the position resolution and esp. accuracy when standing still. That's the driver. Wrt/ the belt, drawback is complexity, including however you plan on controlling belt tension. $\endgroup$
    – Pete W
    Nov 4, 2021 at 22:20
  • $\begingroup$ you don't tell us the current sizing of the pulleys so it's hard to say how this will change. $\endgroup$
    – Tiger Guy
    Nov 4, 2021 at 23:17

1 Answer 1


Yes. you're right. Your stepper motor will produce 3 times more torque, 3 times more resolution.

And 3 times slower angular speed on the lead screw.

  • $\begingroup$ After reading this again I am a little confused. Are you saying that the stepper motor rotating at a fixed speed (frequency A) will now experience 3x less torque when doing a task with this 3:1 gear ratio versus before? Or are you saying the opposite? $\endgroup$
    – Feynman137
    Nov 6, 2021 at 1:09
  • 1
    $\begingroup$ it will experience less torque. the smaller the power wheel the smaller torque it feels. but the other pulley will turn slower. $\endgroup$
    – kamran
    Nov 6, 2021 at 1:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.