Portable EDM abide by the principle of electric corrosion to remove broken taps, it can fast remove broken taps, drill, drift, screw, plug guage, etc., easily process on work pieces at any size, especially effective for large machine tools. a.Could remove broken tap sized M2-M20 b.Small size, light weight, convenient to operate, especially on large size work piece; c.Electrolytic Corrosion principle, no damage to workpiecesï¼? d.Magnetic base, easily to attract on the workpieceï¼? e.Vibration motor improved the efficiency to two or three times; f.Work head is separated, helpful for complex machiningï¼? g.Alarm automatically for certain depth;