Abstract: There is disclosed a ball end mill which has a hemishepherical portion formed at a front end of an end mill body. A pair of tip mounting seats are formed at the hemishepherical portion. A main throw-away tip and a second throw-away tip are secured on the tip mounting seat respectively such that the axial rake angle of the main tip is set at a negative angle and the axial rake angle of the second tip is set at a positive angle. There is also disclosed a second ball end mill. In the second ball end mill, only a main throw-away tip is secured on a tip mounting seat. The axial rake angle of the main tip is set at a negative angle. One or more chip breaker grooves are formed on a rake face of the tip.

Abstract: A cutter insert for a ball end mill is disclosed which includes a plate-like insert body having a front face and a side face extending from the front face. The front face has a generally convexly curved marginal ridge defined by the intersection of the front face with the side face. The marginal ridge serves as a cutting edge. The front face serves as a rake surface for the cutting edge while the side face serves as a relief surface for the cutting edge. The cutting edge has a leading portion to be indexed in the end cutting position and a trailing portion to be indexed in the peripheral cutting position. A land is formed on the rake surface so as to extend along the cutting edge. The land has a width gradually increasing in a direction from the leading portion of the cutting edge toward the trailing portion thereof.

Abstract: In a rotary cutting tool for use with at least one cutting insert, a cutter body is rotatable about a rotational axis. The cutting insert is mounted to an outer periphery of a forward end of the cutter body. A chip moving unit is arranged outwardly of an outer peripheral surface of the cutter body for moving chips generated by the cutting insert, to a desirable location. A cover assembly is provided for covering the outer peripheral surface of the cutter body, having a flow passageway defined between an inner peripheral surface of the cover assembly and the outer peripheral surface of the cutter body. An air sending assembly is arranged within the flow passageway for sending air adjacent the cutting insert, toward the desirable location during rotation of the cutter body about the rotational axis.

Abstract: A insert rotary cutter has a cutter body, at least one first cutter insert and at least one second cutter insert for cutting off burrs. The first cutter insert has more than one main cutting edge and end cutting edge. The second cutter insert has more than one main cutting edge and end cutting edge. The first and second cutter inserts are mounted on a forward end of the cutter body releasably. The second cutter insert is disposed so that the main cutting edge thereof has a negative corner angle and the end cutting edge thereof is displaced radially inwardly and axially forwardly of the cutter body, with respect to the end cutting edge of the first cutter insert.

Abstract: In a rotary cutting tool for use with at least one cutting tip, a cutter body has its forward end whose outer periphery has mounted thereto the cutting tip. A chip suction device is arranged outwardly of an outer peripheral surface of the cutter body for drawing chips generated by the cutting tip. The chip suction device includes a generally cylindrical cover unit having a wall for covering the cutter body. The cover unit is supported by the cutter body for rotation relative thereto. A chip accommodating chamber is defined between an inner peripheral surface of the cover unit and the outer peripheral surface of the cutter body. A suction port unit is provided in the wall of the cover unit and communicates with the chip accommodating chamber. A chip guide unit is arranged at the forward end of the cutter body in facing relation to the face of the cutting tip for guiding the chips generated by the cutting tip to the chip accommodating chamber.

Abstract: There is disclosed a rotary cutting tool having a cutter body and at least one pair of end and peripheral cutting edges provided on the cutter body. A covering of a generally cylindrical shape is disposed rotatably relative to the cutter body so as to surround the circumferential surface of a forward end portion of the cutter body to define a chip disposal space therebetween. A guide member is secured to the forward end portion of the cutter body for guiding chips produced during a cutting operation to the chip disposal space. Furthermore, a chip disposal pipe is connected to the covering for removing the chips in the chip disposal space.