When EDtapper is added to RAM of EDM sinker machine it can add tapped/threaded hole into hardened steel. No lead screw is necessary. EDtapper converts 2-axis vertical movement to orbital movement, forming whole depth of thread in single orbital cycle. Tapping unit has up to 3.2 mm (1/8 in.) horizontal movement in 0.02 (0.001 in.) increments. Setup time for unit is only 5 minutes. Familiar control panel of machine controls it.