M12 3 sided Fidget Spinner - Round edges

thingiverse

Print with a brim if your bed isn't sticky - This helps keep the ends securely in place. It takes an 18mm wide M12 next nut that is 10.55mm deep as standard. The center bearing hole is a standard 608ZZ opening. The center hole measures 22.1mm for a precise press fit. Hex nut holes are 18.3mm, requiring a tight press fit that may necessitate using a vice. Since the nuts are wider than the spinner, you need to center them depth-wise.