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 size of bearing because these are commonly available in stores, and are already around us in droves since they are the central bearing in most fidget spinners.
So, if you have retired fidgets spinners in your drawers (probably yes!), you can poke the bearing out and give this prototype of the STEMFIE 608 bearing housing 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.