Fridge Magnet Gear Spinner With Built-In Magnet

Remixed from https://www.thingiverse.com/thing:2583482

Loved the design and mesh of these gears, but I wanted something that didn't need glue or bearings that could come undone. I remixed the medium sized gear to have a free-spinning center piece where a magnet can be inserted mid-print. Tolerance of the inner part is .75mm. This was the sweet spot for my printer - able to print without binding, yet not too loose inside for my liking.

Video of the magnets spinning: https://youtu.be/JzEt2P-PI2s

I'm using two 15mm x 2mm neodymium magnets that I put in the center cavity once the walls are printed high enough.

The cavity extends the height of the print, and is sized so that the magnets can freely move inside. This means that the gear will stick to the fridge on either side.

Included a .stl of the center mechanism, which can probably be printed inside of the other gear models of the original thing. Also included my Fusion 360 project so that it can be further modified to resize, change the tolerance, or add back in the pegs if needed.

Print instructions

Category: Mechanical Toys Print Settings

Rafts: No

Supports: No

Resolution: .2

Infill: 0%

Filament: Hatchbox PLA
Notes:

0% infill works just fine for me, and the top layers still come out perfect. If your printer has issues with the top layers, then use infill. Just check the gcode preview to make sure that the center cavity for the magnet will not be filled in.

I used two 15mm x 2mm neodymium magnets. which is a height of (2mm + 2mm + 1mm) = 5mm off the build plate is the minimum z height when you can place the magnets. The model is 12mm tall, so you've got plenty of time to come in and place them.
Placing the magnets: https://youtu.be/-1uk\_wF6b0E

I just dropped them in while the printer was doing it's thing, but if you want, you can pause the print and move the extruder off to the side. I went for just dropping them so I didn't have to risk weird artifacts showing up due to the pause.