SO TODAY... replacement stepper for the one I burnt out on the Star Mill arrived. Nice big motor. Now, for those unfamiliar with a Star Mill, the Y-axis motor (the one that this replaces) sits parallel with the Y screw, mirrored back onto the screw, with a pair of pulleys connecting them. So, the body of the motor resides inside the cavity of the iron casting of the column.

This is also where the original 180VDC 1/2HP spindle motor sits, as well, on the moving Z-column. Not that I use that - I have an externally mounted Chinese spindle, but never got around to removing the original spindle motor. I mean, what harm can it do?

So... bigger motor goes into the column, re-assemble, swap the A-Axis driver to Y-Axis and reduce the current/coil to 3A. Feels about right. Fire up UCCNC - YEAH, Y-Axis back to life. Let's just check the rest of the axis - X = yes, Z = yes..... CRACK!

So, the original spindle motor traversed down, hit the new longer stepper on the Y-Axis, and decided that the weak link in the chain is the column casting - there's a strip at the base around 10mm in width that had two bolts holding the Y-motor plate in place. Well that's gone now. Tomorrows job - I've got some 10mm steel plate somewhere - time to cut a replacement plate and bolt that in place. Then rewire some of the sheared cables that got trapped between the stepper and the spindle. I *think* all the drivers are okay, but I've plenty of MOSFETs in the post if not.

I think this Star Mill is becoming the pet project of the week for me.