Tired of these fidget spinners yet?

I've been printing a lot of these spinners lately and decided to make a few of my own. They're very basic as far as design goes, but I added a few things that I felt were missing from other spinners. These spinners are about 0.5mm thicker than the bearings. This is because I sand both flat faces of the spinners and brush with acetone to get a nice finish.

I found I got better spins when the outside bearings were closer to the inside. Also, the more weight to the outside meant more momentum and longer spins. With that in mind I made the borders on the "Circles Spinner Smooth" files thick and got them close to the center bearing. From messing with them a little I found I got the best spin from the Circles spinner with an Amphetamine ceramix silver bearing.

More on bearings:
Sure, the Amphetamine ceramix silver bearing works great, but at $6 each I can't afford to make a bunch for my friends, not to mention I'd still have to get the outer bearings. After a little testing I found I could get similar spins with cheaper hybrid ceramic bearings ($15 for 8) by taking the cheaper rubber dust shields off and cleaning the oil out with brake clean and rubbing alcohol. This works because the oil is really only in there because the bearings were made to carry a load (roller skate bearings), so with no load the oil just gets in the way. I've had mixed results with putting the shields back on or leaving them off as far as slowing the spins goes.