Abstract: A method of and an apparatus for automatically setting or resetting a machining-electrode wire on an operating set-up on a traveling-wire electroerosion machine wherein a broken free end portion of the electrode wire is vibrated with a small amplitude while being advanced along a straight line path for the electrode wire defined between a pair of guide members and with which a preformed starting through-hole in the workpiece is located in alignment. This allows a smooth and non-encumbered threading of the flexible electrode wire which has little self-supporting ability through the starting through-hole.

Abstract: An apparatus for making a hollow extrusion die set consisting of male and female die member with their respective shaped male and female bearing surfaces spaced apart and in a predetermined mating relationship from solid male and hollow female die blanks (6,11), respectively, is provided comprising: a wire-cut EDM electrode head assembly (1) having a plurality of wire guide members (1c, 1d) for spanning and axially transporting a continuous wire electrode (3) in a fixed U form path including a predetermined stretch (3a) of the axially transported wire electrode (3) constituting an axially moving EDM wire-cutting edge for the male and female die blanks (6, 11); a first jig member (5) for securely and interchangeably mounting the male and female die blanks (6, 11) in a predetermined and fixed relative position thereon; a worktable (4) for securely mounting the first jig member (5) thereon and being displaceable relative to the wire-cut EDM electrode head assembly (1); and a second jig member (7) for securely mo