Abstract: A process of making a hole in a metal material of a large thickness comprises bringing the tip of an arc electrode wire into contact with the metal material while laterally reciprocating the arc electrode wire to thereby form an entry path on one side of the arc electrode wire and an exit path on the other side of the arc electrode wire within the hole, and causing a pressurized fluid to be introduced into the entry path, guided to the bottom of the hole and the exit path, and discharged out of the hole together with the molten metal lumps.

Abstract: In the consumable-electrode type arc cutting process whereby the work subjected to cutting is fused and severed by means of a continuous electric arc formed between the wire electrode protruding from the contact tip and the work, an improvement is obtained by the additional utilization of a jet of high-pressure water projected out of a water projection nozzle disposed on the outside of the contact tip. The jet of high-pressure water projected from said nozzle is directed to the point of arc formation on the work so as to blow the molten metal of the work away, whereby the severed edges of the work are prevented from being joined again and, at the same time, the dross is prevented from being deposited on the work and consequently the cut edge of the work is finished neatly.