Abstract: A replaceable cutting head stably rotates a head body using a work tool during attachment. An outer periphery of the head body is provided with a plurality of chip discharge grooves extending along a direction of an axis, cutting blades extending along the chip discharge grooves, and a pair of latching faces that are formed by cutting the outer periphery of the head body and are arranged back to back with the axis interposed therebetween at a base end portion along the axial direction. A first chip discharge groove, and a second chip discharge groove having a narrower width along a circumferential direction around the axis than the first chip discharge groove at at least the base end portion along the direction of the axis are included in the chip discharge grooves. At least one latching face is connected to a base end portion of the second chip discharge groove.

Abstract: A ball end mill, which includes long and short cutting edges alternately formed, shows excellent chip discharge performance without sacrificing strength. An even number of cutting edges are formed at intervals in a circumferential direction on a front end of an end mill body rotated about an axis and have rotation trajectories formed around the axis that form a hemispherical shape. The cutting edges adjacent to each other in the circumferential direction with one cutting edge interposed are long cutting edges that intersect with each other on the axis. The other cutting edges adjacent to each other in the circumferential direction with one cutting edge interposed are short cutting edges that include inner peripheral ends at positions distant from the axis. A gash of the long cutting edge and a gash of the short cutting edge connect with each other on a front end side of the end mill body.

Abstract: A replaceable head cutting tool increases the strength of engagement between a tool body and a coupling member without causing damage. A cylindrical mounting unit of the coupling member which is made of a metal having hardness lower than the hardness of the tool body, is inserted into a mounting hole having a concave portion formed on the inner surface of the tool body. The mounting unit is plastically deformed so as to increase in diameter, and the outer peripheral surface of the mounting unit contacts the inner peripheral surface of the mounting hole and is engaged with the concave portion which includes a first wall surface that is inclined toward the outer peripheral side as it moves in an insertion direction of the mounting unit, and a second wall surface that is inclined toward the inner peripheral side as it moves in the insertion direction.

Abstract: A ball end mill, which includes long and short cutting edges alternately formed, shows excellent chip discharge performance without sacrificing strength. An even number of cutting edges are formed at intervals in a circumferential direction on a front end of an end mill body rotated about an axis and have rotation trajectories formed around the axis that form a hemispherical shape. The cutting edges adjacent to each other in the circumferential direction with one cutting edge interposed are long cutting edges that intersect with each other on the axis. The other cutting edges adjacent to each other in the circumferential direction with one cutting edge interposed are short cutting edges that include inner peripheral ends at positions distant from the axis. A gash of the long cutting edge and a gash of the short cutting edge connect with each other on a front end side of the end mill body.

Abstract: A replaceable head cutting tool increases the strength of engagement between a tool body and a coupling member without causing damage. A cylindrical mounting unit of the coupling member which is made of a metal having hardness lower than the hardness of the tool body, is inserted into a mounting hole having a concave portion formed on the inner surface of the tool body. The mounting unit is plastically deformed so as to increase in diameter, and the outer peripheral surface of the mounting unit contacts the inner peripheral surface of the mounting hole and is engaged with the concave portion which includes a first wall surface that is inclined toward the outer peripheral side as it moves in an insertion direction of the mounting unit, and a second wall surface that is inclined toward the inner peripheral side as it moves in the insertion direction.

Abstract: A ball end mill comprises coolant holes and multiple cutting edges in which a rotation locus around an axis line forms a hemispherical shape having a center on the axis line. The cutting edges are formed at intervals in a circumferential direction at a tip of an end mill main body, which is rotated around the axis line. Some of the cutting edges are long edges intersecting each other on the axis line of a tip of the end mill main body, the remaining cutting edges are short edges each having an inner peripheral end at a position away from the axis line. Coolant holes are formed in the end mill main body and are opened on an extended line of the short edge toward the axis line from the inner peripheral end of the short edge in the tip of the end mill main body.

Abstract: A replaceable cutting head stably rotates a head body using a work tool during attachment. An outer periphery of the head body is provided with a plurality of chip discharge grooves extending along a direction of an axis, cutting blades extending along the chip discharge grooves, and a pair of latching faces that are formed by cutting the outer periphery of the head body and are arranged back to back with the axis interposed therebetween at a base end portion along the axial direction. A first chip discharge groove, and a second chip discharge groove having a narrower width along a circumferential direction around the axis than the first chip discharge groove at at least the base end portion along the direction of the axis are included in the chip discharge grooves. At least one latching face is connected to a base end portion of the second chip discharge groove.