Many years ago [ScorchWorks] built an electrical-discharge machining tool (EDM) and recently decided to write about it. And there’s a video embedded after the break. The build is based on the designs described in the book “Build an EDM” by Robert Langolois. An EDM works by creating lots of little electrical discharges…
Source: Homemade EDM Can Cut Through Difficult Materials Like Magnets With Ease