Honeycomb Magnet Grinder, joint lover

I've maintained this magnetic feature since it works exceptionally well and made a few tweaks both functionally and aesthetically.

I've added a small hook for easier handling or to attach a keychain or lanyard, and removed the top and bottom walls so that the infill texture remains visible on both sides, giving it a lighter, more technical look. If you'd prefer a solid surface, simply set the top and bottom layers to 3 in your slicer settings.

The magnet cavities are designed for 8.5mm diameter magnets, but if yours are different, you can scale the cavity to fit. The cylinder in transparency is a negative solid, so the volume subtracts directly from the grinder based on your magnet's size.

Make sure to double-check the magnet size—if you don’t have 8.5mm magnets like the ones in the original design, be sure to resize the cavity and center it properly.

I also recommend keeping supports enabled for the hook part, as it may not print perfectly without them. Be mindful of the fill settings you choose. By default, I’ve used honeycomb, but you can swap it out. Just avoid dense fills like 3D honeycomb volumetric infill, as they may be too bulky.