Here is an alternative to 3d printed ball or gear bearings which are usually hard to print or have high tolerances (which is bad for bearings).
This bearing is designed to have low tolerances and to be easily 3D printable.
I recreated and adapted the model after a tutorial I found on YouTube
The original version of this model can also be found on Thingiverse:
https://www.thingiverse.com/thing:2375124/files
M3x12 Screws: 8x
M3 Nuts: 8x
For assembly use the provided pictures as a guide
Nozzle: 0.4mm
Layer height: 0.2mm or less
Seam position: random
Material: PLA/PETG
The author remixed this model.