Quote Originally Posted by Robin Hewitt View Post
The frictional losses on a ball screw are low. The screw can turn the nut if you have the means to push hard enough.

Spin the motor by pulling on the handle and you can feel if something is binding. Should be smooth
Ah, what is the lead on the screw... I hadn't realised it was that big a lead. But what stops the quill dropping under its own weight then when the motor is powered off? Or is there sufficient stickiness in the cogging to stop that?