Quote Originally Posted by m_c View Post
So things seem to be mechanically OK.

Next easy test, can you rotate the stepper motor with the lathe powered up?
This will tell us if the stepper driver is doing anything.
The stepper motor driver and stepper motor are definitely doing something as they can partially rotate the tool but stop after about 30 degrees at which point the lathe hangs and disconnects from the PC running the turning software.

When I get some time this weekend I was going to remove the stepper motor from the ATC to see if it can complete full rotations without load.