Per a request, here's a Cleveland Indians fidget spinner that I came up with. This spinner uses (3) 5/16" nuts and (1) 608 skateboard bearing. This spinner is about 3-1/2" in diameter overall.
EDIT: I uploaded a V2 model that uses (3) 1/2" ball bearings in lieu of the (3) 5/16" nuts.
If your printer can bridge over the hole for the nuts, you won't need supports.