A safety feature of spice grinders and coffee grinders is an interlock tab, which means the motor will only run when the button is pressed and the lid is held down. It is a good idea because it means you don’t have the grindings flying out or fingers getting poked in. However, when the tab is a small nub sticking out of a transparent plastic lid, which gets more brittle over time, it also becomes a potential point of failure. We dropped our lid yesterday and the tab snapped so time for the bin… or for a 3D printed solution.

I’ve designed a simple ring with an integrated tab that can sit underneath the lid, meaning we can keep the grinder in service. Printed in black, you can barely even see it in the photo above but you can see the ring on its own if you want. I’ve made the tab larger than the original to get as much strength as possible without messing around with print orientation and we’ll see how it lasts. I reckon it will do for a good while and, when it breaks or gets mislaid, I can print off another 4g or so of filament (cost ~5p… so much cheaper than trying to buy a replacement part).

As a safety note, there is a degree of additional risk as you could now run the motor without the lid on. Since we don’t have children running around, I’ll keep it as a loose accessory but it could be glued on for better safety but harder cleaning. The model is published on Makerworld if you need it or something similar; I’ve also uploaded the OpenSCAD file so you can adjust the parameters if you have a different grinder that works on similar lines.