This modular and magnetic counter has a wide variety of uses. I originally designed it to serve as a score keeper for board games, but it works very well for anything in which you need to track of some numerical value. The magnets I used were purchased in a 100 pack on Amazon (Link Here!). I went through a number of prototypes before finding the right size magnets, and the right geometry for the indents/detents. I think this version is the perfect balance between smooth operation, and snappy holding power. Beyond being a counter, it makes for a satisfying fidget as well!

The magnets are quite strong, and consistently sized at 8mm diameter, and 2.95mm in height. If you are using different magnets, I suggest printing the “Magnet Test” plate to ensure a proper fit. This design is intended to be a press fit, no glue required. The model is parametric in Fusion, and simple to modify for various magnet sizes.

Even if you are using the same magnets as those linked, I suggest printing the “Magnet Test” plate, as these can serve as helpful tool for consistent polarity installation. I installed all the magnets facing the same direction on the faces with indents first, and then simply added a magnet to the now installed face, and pressed its neighboring disc into place.

I printed two versions, one in black and one in white. The white certainly looks cleaner, but the numbers are slightly harder to make out in pictures. I may create an AMS and non AMS version in the future. Acrylic markers work wonderfully on PLA, should you want to color your numbers!