Summary UPDATE- 11/112015 Version 2 released : Smoother edges 10/20/2016 As requested added a ready to print stl with all 3 parts. Video :https://youtu.be/NOGPQmb8KG8 Based of https://www.etsy.com/shop/RestlessHandsToys All tolerances are exact and ball bearings need to be press fit in with a vise or equivalent device. If plastic cracks, increase stl model by 1-2 percent and print again. Standard 608ZZ Shielded 8x22x7 Miniature Ball Bearings used in this model. The center Bearing can be switched for a 608ZZ/C Ceramic Ball Bearing for increase spin time. Spin on!