Magnetic Gear Spinner Fidget

This is a simple but effective gear spinner that uses a herringbone design to keep the gears aligned, with magnets to stop them flying apart.

The design uses 20mm x 2.5 mm neodymium magnets.

The files include 3 different-sized spacers that are pressed into each side (no glue is needed).
Each of the spacers can be used to hold in a different number of magnets:

2mm spacer - 4 magnets
3.25mm spacer - 3 magnets
4.5mm spacer - 2 magnets

I have found that 2 magnets are a bit weak and 4 a bit too snappy, but I have included them as not all magnets are equal.

The magnets I purchased are also only 19mm when measured, and these work fine.

To assemble, print 2 of the gears and 2 spacers of your chosen size. (PLA, 0.2 layer, 0.4 nozzle) 
Lay one spacer flat down on a table and press the gear onto it.
Add the magnets and then flip it over and press the other side in as well.

When assembling the second spinner, mesh the gears and ensure the magnets are aligned correctly.
Both the magnets and the gears will only fit one way.

They take a little bit of "running in", but they get a good rhythm going once you get the knack of it.
I find they spin best when held between a thumb and forefinger, and spun horizontally.