Here is a quintuple spinner used with 1 standard 608 skateboard ball bearing (Ø22mm) in the middle and 5 M14 Hex nuts on the outside.
You can also add optional M3 Hex nuts (x3 on each nut holes max).
Very good inertia and around 30s to more than 2min of spinning (depend on your bearing and spinner balance).
Heavy spinner for an amazing gyroscopic feeling !
Hole diameter is Ø22.1mm for good bearing mounting.
You can use a hammer and a hard flat surface for fitting the nuts, or sand nut holes with a small file, if you had shrinking material during your print.
It's OK if nuts are not centered but they must be on the same flat surface (Standard M14 nuts are 3mm higher than the spinner height)
Stop using your pen clicker and start hand spinning !