One of the STEMFIE goals is to integrate non-printed components with 3D-printed parts, making it possible to create extensive builds containing motors, electronics, and commonly available mechanical parts.
This image shows an early attempt to make a 3D-printed bearing housing for the 608 standards. I chose this bearing size because it is commonly available in stores and is already around us in droves since it is the central bearing in most fidget spinners.
So, if you have retired fidget spinners in your drawers (probably yes!), you can poke the bearing out and give this STEMFIE 608 bearing housing prototype a try. You can download and 3D-print the 3mf file here. Note that the retaining ring for holding the bearing in place is a short piece of 1.75 mm filament.