This gear is a replacement for the gear in the Dremel Model 220 workstation. To mount it to the original shaft simply hammer it in and it will hold well. I recommend printing it in PLA+ for it's high resistance to abrasion or another high strength material like PC. print with 100% concentric infill or with infinite perimeters. Print it on the flat side. Requires no supports. Remember to pre-tension the spring and set the set screws tight so there is no play and also lube with a plastic safe grease like Super Lube. If there are any questions leave a comment. Enjoy!