Union Tool Company

Hideo Wakui

Shoichi Takahashi

Ichiro Katayama

Hidehito Watanabe

A drill including a chisel edge provided at a tip end portion, a spiral first chip discharging groove and a spiral second chip discharging groove, land portions provided between the first chip discharging groove and the second chip discharging groove, and a cut blade provided at an edge of a rake surface of the first chip discharging groove, characterized in that the first chip discharging groove and the second chip discharging groove are provided asymmetrically with respect to a drill rotational center and a land portion behind the first chip discharging groove is larger than a land portion behind the second chip discharging groove.

Drill

A method of joining a sintered hard alloy member such as a cylindrical rod-shaped twist drill bit blank made of material whose main component is tungsten carbide to a softer metal member such as a stainless steel shank includes the steps of connecting the hard alloy member and the metal member to separate electrodes and applying a longitudinally directed force couple to the hard alloy member and metal member to press end faces of the members together to form an electrically conductive contact region, and passing a pulse of current through electrodes and of sufficient energy to melt the two end face regions of the members, thereby welding them together. Preferably, the end face of the metal member has a convex conical shape.

Growing community of inventors

Nagaoka, Japan

Hideo Wakui