I have a stepper motor linear actuator assembly like this for example, but the stepper shaft seems able to move axially back and forth - hence when I change direction it has to do a few rotations, forcing the ballscrew against one end or the other, before the rail platform itself starts moving. Why could this be happening and what can I do to fix this?

If anyone has a diagram showing the internals of a NEMA stepper motor that would be really helpful also. I've seen many on the internet but none showing me enough to understand this problem. Many thanks!


Constrain the driven shaft and use a coupling to the motor.

  • $\begingroup$ Not really enough space - the shaft is already coupled to the ballscrew, leaving little space for this. I've got a backup plan to jam a thrust bearing up against the other end of the shaft at the back of the motor, but this will decrease the performance, and it would just be preferable to just fix whatever is wrong inside the motor? $\endgroup$ – Oliver Walters Jan 15 '20 at 19:16
  • $\begingroup$ I would look at controlling the shaft because some motor cases flex too much... $\endgroup$ – Solar Mike Jan 15 '20 at 20:43

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