Ball screw appears to be binding, but is it ...?

[CNCOlly]

Thanks for your advice. I tried clearing out and lubricating the ball nut. This appeared to clear the fault and worked fine for a couple of days.

The stepper is a closed loop stepper. I decided to swop it out and in doing so found a broken cable.

It was obvious after I found the fault. As the cable chain curled over it caused the fault to occur, this resulted in the issue happening at the same place every time.

Lesson learned, anyway after all that oiling and greasing it's running like a dream.

Thanks.