... DRO: optional KN-EDM- SMALL HOLE-DRILLING MACHINE -43Main features:1. Capable of processing deep hole with diameter 0.2-6 ... hole, filter hole, nozzle hole, air hole, multi hole, extra deep hole and so on.Capable of processing conduct material, even semi-conduct material, especially suitable for ... curved plane of work piece.Capable of eroding broken drilling head, screw tap in work piece, instead of ...