Magnetic Toy

This doesn't do much, so it's just a nice fidget toy for the moment. Created as an exercise, and to practice making radial patterns. I'd suggest scaling the diameter of the pin down a bit, but only a few percent. It fit for me, but had to be driven in (which was perfect, since I wanted it to stay put). Alternately, you could make it significantly longer and use it as a lever to turn the device.

It uses magnets from Amazon (https://www.amazon.com/dp/B09Y5VPXNT - LOVIMAG Neodymium Magnets Bars, 80 Pcs Strong Rare Earth Magnets Bar, Small Rectangular Industrial Magnets for Craft, Fridge, Science, Office and Tool Storage 10x5x2mm) which fit nicely in the pockets of both halves of the device. 

I arranged them in a ring of same-oriented pairs (e.g. all north poles outward or inward), though alternating them in matched pairs could be interesting.

It was originally designed to have a tiny bolt hold them together, but it seems unnecessary. I'd like to make the handle/plug a bit wider for more comfort in turning, and remove the knobs on the outer body (since they hardly seem necessary, and only complicate printing.

This actually could be a basis for a magnetic brake, I think; easy to turn, but really wants to be in a static position. It turns with satisfying, audible “clicks” for each paired position of magnets. It rotated smoothly, but a little graphite for lubrication seems to me to be a good idea.

Photos now added, and I added a “hat” for the inner part to make it more pleasant to spin. It can be solvent welded or glued on, but for me, the fit is tight enough that it can be removed by hand, but doesn't fall off.

If this type of magnetic device has a name, I'd love to know! It seems to be very similar to this, amongst others: https://www.printables.com/model/371361-magnetic-tactile-detent-fidget-toy (though I didn't use that as inspiration or have foreknowledge of its existence).