Gilbert Gagne wrote:
They were using EDM (Electrical Discharge Machining) to erode the stud. It will cut just about any metal. It's especially handy for cutting/drilling materials that would be too hard to machine otherwise (like solid carbide.)At a machine shop some time ago I observed them removing a broken stud from an Alfa cylinder head. The machine burned out the stud remains by means of an electric arc. Don't know what frequency or amperage. It did not seem to touch or affect the aluminum in any way.