X axis stepper motor set screws

Shapeoko Pro XXL,

I was having some issues with the X axis slipping/jumping while running parts. I checked the belts and all seemed to be fine so I pulled the X axis stepper motor and think I have discovered the issue. Neither set screw is lined up with the flat part any longer, so they have certainly jumped at one point in time. I have removed the set screws but cannot seem to get the gear off to reset it. Any suggestions on how to get this off, it is not just sliding off. Also if I do manage to get this off do I need to replace the set screws at this point? And if so how would one go about that…are there replacement parts to order or what are the set screw sizes and threads.

The set screws are M3 set screws — some folks use M3 SHCSs of a suitable length (8–10mm).

I would put a witness mark on the pulley and shaft, see:


A little heat on the gear might help it expand a bit and budge. Careful not to put too much heat into the shaft/ stepper.

Other option is to use a small gear puller or two large flathead screwdrivers on each side underneath has worked for me.

Don’t force anything and you’ll be ok. Also McMaster has bolts with a locking patch.


good suggestion didn’t even think about that, so I put a witness mark on the pulley and shaft, still running into the issue of the X skipping/grinding even when trying to jog the machine. The witness mark between the pulley and shaft however did not move so maybe not a set screw issue at this point. So any other suggestions of what I can be running into here? Belt too tight?

Open to any suggestions at this point.

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