by Jacob Morgan » 2 Jun 2017 0:13
The common term for removing metal with electricity would be EDM, electronic discharge machining. It uses a wire fed into the workpiece and it erodes the metal it touches. Everything is done in a liquid bath. It is used in tool and die shops. It is good for complex shapes. Years ago Home Workshop Machinist published do-it-yourself plans on how make a unit.
The post in the link above is not EDM--not sure what the proper name for it would be. Interesting and creative method, but not something that could not be done in minutes with spot annealing with a drill press (for the tension wrench shown). Might be good for intricate tools that could otherwise only be done with lots of file work.