Review on Revolutionary Filament Grinder: Ultimate Corrosion Removal Solution by Dave Hock

they fit on the angle grinder and work, but without the threaded nut they are very difficult to remove. The standard wrench that comes with the grinder won't remove it as you can't push it deep enough into the cup. had to modify the key with longer pins to remove them. not worth the trouble. Update: don't worry about taking them off, after about 20 minutes of sanding homemade paint there's not much left of it