This was totally based on this nice and well machined rotating dices:
https://www.youtube.com/watch?v=r2N7ZlqV9eQ
To make one, you'll need:
4 small bearings (3x10x4 mm) lke this ones:
https://www.amazon.com/Fishing-Shielded-Miniature-Bearings-VXB/dp/B002BBF59C
14 little magnet balls (3mm):
https://www.magnetstore.co.uk/neodymium-sphere-magnets/3mm-sphere-magnet/
a 45mm length metal rod, with 3mm in diameter. I used a 2.7mm, since I don't have a
press to fit the bearings tightly in the rod. By rule, the tighter, the better. I think 2.8mm
will work. I don't have a lathe either.
two 15mm length screws, 3mm in diameter (M3).
Print the parts with 0.1 or 0.2 layer height. I printed the parts with 20% infill. The dice discs were printed with 50% to give them some weight and inertia momentum.
Snap the magnets by pressing them against the proper holes (indicated in the image) with a hard surface (a ruler, for example). The magnets holes were made to let the magnets free for spinning, to ensure the attraction force between them (not repulsion). Depending on how the magnets balls were made they can have magnetic poles changing across its surface - or from inside to outside. So, if you get the first type, they will spin and attract each other.
The images show the order of assembly.
Due to the lose magnets, the toy make a nice sound when spinning.
There is a small margin of error, it can stop between numbers, but it doesn't ruin the funny experience.
Video here: https://youtu.be/ZFF2bTKgedE
Print Settings
Printer brand:
Prusa
Printer:
I3 MK3S
Rafts:
No
Supports:
Yes
Resolution:
0.1
Infill:
20% (50% for the dices)
Filament brand:
Generic
Filament color:
Any
Filament material:
PLA