Patent ID: 8217297

Claim:
An electrical discharge machine comprising an EDM electrode, an electrode holder, and an electrode guide, wherein: the electrode holder and the electrode guide cooperate to align the EDM electrode along a machining axis of the electrical discharge machine; the EDM electrode comprises an effective electrode diameter d 1 ; the electrode guide comprises an internal passage profile that transitions along the machining axis from a substantially circular cross section comprising a diameter d 2 to an apexed cross section; the circular cross section of the electrode guide comprises an electrode entrance aperture; the apexed cross section of the electrode guide comprises an electrode exit aperture; the EDM electrode extends from the electrode holder through the electrode entrance aperture of the electrode guide and out of the electrode exit aperture of the electrode guide; the apexed cross section of the electrode guide is aligned relative to the circular cross section of the electrode guide such that apexes of the electrode exit aperture lie outside of a circumferential portion of the circular cross section; and a restricted circumferential portion defined by the apexed cross section comprises a diameter d 3 that is greater than the effective electrode diameter d 1 .