My sister got me a coffee grinder for my birthday. Not just any coffee grinder, but a vintage stainless steel Rubis Inox Peugeot (almost exactly like this one). A car boot sale treasure find.
The only problem was, it didn’t work. The blade turned in slow jerks. There was no way it was going to be grinding any beans, it might succeed at pushing them around a little though. So I did what any self respecting Steam Geek would, and took it apart.
It’s a simple enough vertically mounted electric motor with a spring released on/off button. No safety interlock- this was built back in the day when companies didn’t assume their customers were all idiots.
The problem was, as I’d suspected, carbon deposits, and maybe a little oxidation, on the contact surfaces. I flipped the carbon bushes around so they were presenting a flat rather than curved surface and cleaned the commutator up with an emery board. After a little bit of slapstick getting the feed springs for the bushes back in place it all went back together again simply.
The blade now spins so fast it scares me and there’s an interesting smell of ozone after each spurt. What I really need are some coffee beans to test it properly.