This is a main body with the mounting lugs for NEMA 14 round stepper motors. The x and y axes are adjusted neatly with a change of the parameters, but the z-axis is rather a hack because of the need to put the motor outside instead of inside. I think it is correct, although the wide z-motor lugs might get in the way of the Allen key when mounting the optics.
(edit: I now see that the motor mounting lugs are M3 tapped, rather than M3 clearance 
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main_body_NEMA_14.stl (2.0 MB)
main_body_NEMA_14_counterbore.stl (2.2 MB)