I got additional stones for my Sharpmaker (diamond and ultrafine) and had been carrying them separately in another bag. So I decided to design my own case that keeps all the rods together as compactly as possible, while also leaving the rods easily visible.
I've printed the regular case, though I've added a hollowed out case that may be preferred to avoid any unnecessary stringing inside the case.
I printed my version with a 0.6mm nozzle at 0.4mm layer height, but of course a 0.4mm nozzle should be fine too. No supports needed if you print the case vertically.
Before printing the full case, to avoid wasting filament, I recommend printing the lid and cut-off case included in the 3MF file.
Adjust print size % by 1-2% should be enough. Once you've got the right size, you can print the full size case (the lid you already printed doesn't need to be printed again).
The author hasn't provided the model origin yet.