UPDATE 17DEC2017: I have added a new frame that is larger, "Spinner Press XL". This is to accommodate larger spinners but also because I've found it handy to use the press for other purposes entirely. Also, I have changed the thread pitch of the large screw. It now offers more mechanical advantage and is much easier to turn. I have removed all older designs to clean up the downloads.

I designed this to make it easier to press fit the bearings in to fidget spinners. It presses them in to be perfectly flush.

This works for pressing large ball bearings in to place as well. I tested it with 1/2" ball bearings. You can also use it to remove those bearings.

To use, hand press the bearing in to the spinner a little and then insert in to the press and turn the screw until it's flush. I have found it easier to insert the bearing from the top side of the printed spinner as the bottom tends to flare out a bit on the first layer of printing.

I over engineered this a bit as I wanted to ensure that I wouldn't break it. It's thicker because I didn't want it to bow or bend and I added material around the screw to prevent stripping of the threads.

1 x 608 bearing for main screw
1 x 5mm ID / 10mm OD / 4mm High bearing for removal screw