Electrode for effecting electro-chemical drilling operations comprises tube of electrically conductive material open at both outer ends, which has cylindrical inner/outer walls, flat walls and coating of electrically insulating material

摘要

The electrode for effecting electro-chemical drilling operations comprises a tube of electrically conductive material open at both outer ends, which has cylindrical inner and outer walls, flat upper and lower walls and a coating of electrically insulating material (2a,2b) on the outer wall. The coating of electrically insulating material is excluded from a part of the upper side of the tube (1) used for connecting the electrode to an electrical feed source. The insulating material is also absent from a further part (1e) of the outer wall of the tube. This further part runs as a ring around the tube.