Lately I was searching for 3D-printable ball bearings. I couldn't find what I was looking for. Everything was either too large, not smooth enough or didn't have a spacer in between the balls to prevent them from rubbing on each other. Designing the best bearing possible quickly became my side project. The smallest functional bearing I have managed to make is only 5mm wide! Altough these are really hard to print succesfully.

I have set the clearance between the balls and the edges to whatever worked best for my printer (Creality Ender-3 V3 KE). Since I don't have any other printers to test with, I would like to know how the clearance turned out for you. I will try to set the clearance to a value that works for everyone.

If you need a bearing with specific dimensions or if you want to change any other parameters (inner_diameter, outer diameter, width, clearances, overhang_angle) you can look it up in Onshape or use the link. The document is called: "Small 3D Printable Ball Bearings". You have to make a copy of this document to change it. https://cad.onshape.com/documents/bb69383010213044505050b4/w/692fcebf15b219d24ba31224/e/b93e44e6f782381cab2d5d50

Keep in mind that printing these is not easy. The main difficulties being: bed adhesion and tight clearances.

Tips:

• Seam position: random
• Flow ratio: 0.95
• Lower outer wall speed (I set it to 40mm/s)
• Layer height: 0.2mm is fine but smaller will result in a smoother bearing.
• If your filament diameter is not exactly 1.75mm you should compensate for this (mine for example was 1.68mm)
• Clean the print bed for better adhesion
• If the balls are stuck, try grabbing the bearing by its center and rubbing it on a grippy surface

Good luck printing!