Is it possible to introduce torque on a lead screw (with no magnets attached to it) with a moving magnet that can only move parallels to the screw?

(the lead screw is ferromagnetic)

Something like that:

enter image description here

  • $\begingroup$ I can't see why not, as long as your magnet is strong enough and surrounding components aren't magnetic. $\endgroup$
    – jko
    Commented Dec 17, 2020 at 18:00
  • $\begingroup$ I edit my question, is there a magnetic configuration to do that with the magnet moving parallels to the screw? $\endgroup$
    – Simon
    Commented Dec 17, 2020 at 18:17
  • $\begingroup$ all motors are basically rotating a magnet around a shaft, so this is just a different application. But you will find that low speed isn't the sweet spot for this. $\endgroup$
    – Tiger Guy
    Commented Jan 1, 2021 at 4:55

1 Answer 1


Yes, it is POSSIBLE but it's not very practical.

Take a look at how switched reluctance motors work. Essentially, torque is generated by the motion of the soft magnetic material to align itself with the magnetic field lines. You're using a hard magnetic material (ferromagnetic), but the approach is essentially the same.

IT would work a lot better if you can introduce some level of asymmetry to your screw cross sectional area, but if you don't want to do that, you can get an effective elongated magnetic profile by aligning your stators with the thread pitch of your screw.

  • $\begingroup$ I'm not sure i fully understood. I updated the original question, can you further elaborate on your proposal? $\endgroup$
    – Simon
    Commented Dec 17, 2020 at 22:15
  • $\begingroup$ imgur.com/a/52qBWZt $\endgroup$ Commented Dec 17, 2020 at 22:30
  • $\begingroup$ that's geniuses. did you saw a video of someone actually doing it? i would love to see it, cant find any also, if i change the polarity of one of the magnets, will it unscrew? $\endgroup$
    – Simon
    Commented Dec 17, 2020 at 23:02
  • $\begingroup$ btw, can you suggest a drawing for the asymmetry that you talked about? maybe i can do it $\endgroup$
    – Simon
    Commented Dec 17, 2020 at 23:27
  • $\begingroup$ imgur.com/a/JVwVcLy Upvotes please if you find this helpful $\endgroup$ Commented Dec 18, 2020 at 1:25

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.