No glue needed!
Press the 608 bearing cartridge into the center first - easier to align this way. You want to make sure it is flush on either side. The 608 bearings are the common skateboard bearing size with a 22mm OD
1/2" loose ball bearings press in and snap into center of holes with an audible click. They will rotate in their sockets and not come out. The weight will be balanced when spinning because there is no guess work as to where the center of the hole is.
Buttons have a shoulder for the inner bearing race to ride on so there is no rubbing and you can hold them tightly for fast spins. They are also just wide enough so that the spinner can be spun on a tabletop or hard surface.
The 9 and 10 ball spinners are very heavy. The 6 ball is ideal for one hand spinning and small hands.
Designed using Autodesk Fusion 360