Mitsubishi Materials Corporation

Mitsubishi Jukogyo Kabushiki Kaisha

Mitsubishi Kinzoku Kabushiki Kaisha

Hiroshi Kasutani

Yutaka Adachi

Koji Hashimoto

Yasunori Murakami

Kazuo Takasaki

Takao Koyama

Kouji Hashimoto

Takashi Kashiwagi

A cutter body for counter sink drilling fiber reinforced plastic materials, such cutter body having a pilot portion at a distal end of the cutter body and a countersinking section formed adjacent to the pilot portion in a region on the base end side of the cutter body. The countersinking section comprises three unit machining sections disposed with equal angular intervals in the circumferential direction of the cutter body. Each unit machining section comprises an abrasive layer formed by electrodepositing diamond abrasive grains on a conical surface in turn provided on the cutter body with a chip discharge groove and a finishing edge overhanging from the abrasive layer by an amount t and disposed in order successively rearward in the direction of rotation of a drill or cutter. The finishing edge is formed on a hard sinter, which contains diamond grains as a main ingredient, on a laminar sinter.

Counter sink drill

A high performance drill bit is presented for precision drilling of holes in hard-to-drill materials, such as a carbon fiber reinforced plastic material. The drill is a gun drill type having a pair of flat flutes and a pair of air holes for delivering coolant and/or lubricant. The main feature of the drill is the provision of two pairs of cutting edges formed on the intersecting ridges formed at the leading sides of the flank surfaces with the flute surfaces. At the tip of the drill bit, a pair of primary cutting edges, having a point angle .alpha., is disposed. It is followed by another pair of secondary cutting edges, having a point angle .beta., where .alpha.&gt;.beta.. Physically, this means that the secondary cutting edges are inclined more toward the drill axis than the primary cutting edges. The secondary cutting edge is followed further by another flank surfaces which are even more inclined toward the drill axis.

Drill bit for advanced materials

A drill bit comprises a body of a cylindrical shape having a straight groove of a generally V-shape formed in the circumferential surface thereof and extending along the longitudinal axis thereof. The bit body has a drilling fluid passageway extending longitudinally therethrough. One of the two side faces defining the longitudinal groove has a radially inwardly-disposed convex surface of a semi-cylindrical shape and a flat surface extending radially outwardly from the semi-cylindrical surface of the periphery of the cylindrical bit body. The semi-cylindrical surface terminates at its forward end in an arcuate inward cutting edge while the flat surface terminates at its forward end in a straight outward cutting edge. The arcuate inward cutting edge is offset from the straight outward cutting edge when viewed from the forward end of the bit body.

Drill bit

Growing community of inventors

Gifu, Japan

Hiroshi Kasutani