This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/bozH72ykOth

Video of the operation can be found here: https://youtu.be/vzOQCr7_uFk

This has been redesigned to use a 608 ball bearing. You'll want to search for a good center bearing for a fidget spinner. These tend to be unshielded and un-lubricated bearings.

The four colored bearings in the photo are shielded bearings. These are used only as weights. And they tend to be less expensive.

Parts are friction-fit together. I used a bench vice to press them together nicely.