I made a slight boo boo in not allowing the chance to have the stepper on either (or both) side(s) and next time I’d probably print the rings inside each other because I though I would break one of them putting the rings inside each other… Some slight warping of the ABS inside the holes means they had to be drilled out a little to fit the bearings, but this is quite normal… the grabcad model was really good but obviously some of the balls have different designs so a little modification is required….