Abstract: In the ball end mill, at least two end cutting edges are extended to the vicinity of an axis at a tip portion of an end mill main body which rotates around the axis. In two gashes in which two end cutting edges adjacent to each other in a circumferential direction are formed, a first gash on the end mill rotation direction side extends beyond the axis on the tip of the end mill main body and a second gash on the rear side in the end mill rotation direction does not exceed the axis. A first tip flank face which intersects with the first gash through a first end cutting edge is extended toward a second tip flank face which intersects with the second gash through a second end cutting edge.

Abstract: The holder for a head replacement-type cutting tool is provided with a holder main body and a tubular coupling member 3 which is housed in an attachment hole formed on the holder main body and made of a metal material lower in hardness than the holder main body. A recessed part is formed on an inner circumferential face of the attachment hole, the coupling member is engaged with the recessed part by firmly attaching the outer circumferential face thereof on the inner circumferential face of the attachment hole, and the coupling member is provided with an attachment screw part which is screwed into a head-side screw part formed at the replacement-type cutting head.

Abstract: A tapered end mill includes a cutting edge portion which includes an end cutting edge which extends from an inner peripheral side of an end mill body to an outer peripheral side thereof and a tapered peripheral cutting edge which extends from an outer peripheral end of the end cutting edge to a rear end side and has a cutting edge diameter which gradually increases toward the rear end side, the cutting edge portion being provided on a distal end portion of the end mill body which rotates around an axial line. A truncated conical tapered neck portion having an outer diameter which gradually increases toward the rear end side is provided on the rear end side of the cutting edge portion, and a columnar straight neck portion is provided about the axial line between the cutting edge portion and the tapered neck portion.

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: In a formed end mill, a peripheral cutting edge has a smaller-diameter cutting part and a larger-diameter cutting part. An imaginary line obtained by lining up a deepest point of a flute bottom of a chip discharge flute, which appears in a cross-sectional view perpendicular to an axis of an end mill body, in an extending direction of the chip discharge flute is defined as a virtual flute bottom line. A flute helix angle, which is formed between the virtual flute bottom line and the axis, in a side view when the end mill body is seen from a radial direction orthogonal to the axis, is 0 degrees or more at a distal end part of the chip discharge flute in the axial direction, and increases gradually from the distal end part toward a posterior end in the axial direction.

Abstract: A roughing end mill includes: an end mill main body rotated about an axis; and four or more of outer peripheral cutting edges provided on an outer circumference of a tip part of the end mill main body spaced apart in a circumferential direction, each of the outer peripheral cutting edges extending from a tip of the end mill main body to a rear side, wherein each of outer peripheral cutting edges includes a waveform cutting edge that is concaved and convexed in a radial direction, a phase is shifted within one pitch, and the waveform cutting edges of the outer peripheral cutting edges have one or more parts, in which phases of the waveform cutting edges are sequentially shifted multiple times toward a rear end side of the end mill main body, and shifted the same multiple times toward a tip end side of the end mill main body.

Abstract: An end mill body comprises: bottom blades formed at ridgelines where gashes and tip flank faces intersect, the gashes are formed at the tips of chip discharge grooves. At least one of the bottom blades serves as a long bottom blade that extends toward an inner peripheral side longer than the remaining bottom blades. The end mill body also has coolant holes formed between the chip discharge grooves. A coolant hole which is located between a chip discharge groove of a gash and a chip discharge groove located behind the chip discharge groove in a rotational direction is open to the tip clearance face of the long bottom blade. A coolant hole which is located between the chip discharge groove of the gash and a chip discharge groove located in front of the chip discharge groove in the rotational direction is open to the gash of the long bottom blade.

Abstract: A head replacement-type cutting tool having a holder provided at the attachment hole with the fitting part formed in a tapered shape, and the leading end face is perpendicular to the central axis. The attachment part formed in a tapered shape protrudes on the cutting head from the rear end face perpendicular to the central axis of the cutting part. The cutting head is attached to the holder in such a manner that the attachment part is fitted into the fitting part by screwing the female thread part with the male thread part and the leading end face is in contact with the rear end face. The inner diameter to outer diameter ratio d/D1 which is a ratio of the inner diameter d of the fitting part before being fitted in relation to the outer diameter D1 of the leading end part of the holder is from 0.5 to 0.8.

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 ball end mill comprises a gash provided at a front end portion of a main end mill body rotated about an axis; and at least one cutting edge which has a rotational trajectory around the axis that forms a convex hemispherical shape having a center on the axis. The cutting edge is formed at a peripheral edge portion of a wall surface of the gash. A difference between a first and second included angles is within ±7°, where the first included angle is formed between the axis and a straight line connecting the center with a cutting edge position at which a depth of the gash is maximal in a cross-section orthogonal to the cutting edge, and the second included angle is formed between the axis and a straight line connecting the center with a cutting edge position at which a rake angle of the cutting edge is maximal.

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: Provided is a replaceable machining head wherein: fractures on the tool attaching portion do not occur; the production cost is minimized; the tool life of the working tool will be lengthened; and the head body is free from a risk of falling off during replacement. In the replaceable machining head, a cutting edge section is formed on the front side of a head body; a tool attaching portion to which a working tool is to be attached, is formed on the rear end side of the cutting edge section; tool attaching faces are formed in the tool attaching portion; the surface of the head body 1 is coated with a coating film; and the number of droplets or macro particles having convex shapes with a size of 0.3 ?m to 5.0 ?m, is 200 or less, per area of 40 ?m×60 ?m on the surface of the coating film over the tool attaching faces.

Abstract: An exchangeable head cutting tool contains a tool main body made of a hard material and a connecting member made of a metal material having a lower hardness than the hard material. The tool main body and the connecting member are joined by inserting a cylindrical mounting portion of the connecting member into a mounting hole formed in the tool main body, and by plastically deforming the mounting portion so as to expand a diameter thereof, thereby bringing an outer peripheral surface of the mounting portion into close contact with the inner peripheral surface of the mounting hole and thus making the outer peripheral surface of the mounting portion engage with a concave portions of the tool main body. A diameter expanding member having a higher hardness than the connecting member is press-fitted into and fixed to an inner peripheral portion of the mounting portion.

Abstract: In the ball end mill, at least two end cutting edges (9) are extended to the vicinity of an axis (O) at a tip portion of an end mill main body (1) which rotates around the axis (O). In two gashes (7) in which two end cutting edges (9) adjacent to each other in a circumferential direction are formed, a first gash (7A) on the end mill rotation direction (T) side extends beyond the axis (O) on the tip of the end mill main body (1) and a second gash (7B) on the rear side in the end mill rotation direction (T) does not exceed the axis (O). A first tip flank face (8A) which intersects with the first gash (7A) through a first end cutting edge (9A) is extended toward a second tip flank face (8B) which intersects with the second gash (7B) through a second end cutting edge (9B).

Abstract: Provided is a replaceable machining head wherein: fractures on the tool attaching portion do not occur; the production cost is minimized; the tool life of the working tool will be lengthened; and the head body is free from a risk of falling off during replacement. In the replaceable machining head, a cutting edge section is formed on the front side of a head body; a tool attaching portion to which a working tool is to be attached, is formed on the rear end side of the cutting edge section; tool attaching faces are formed in the tool attaching potion; the surface of the head body 1 is coated with a coating film; and the number of droplets or macro particles having convex shapes with a size of 0.3 ?m to 5.0 ?m, is 200 or less, per area of 40 ?m×60 ?m on the surface of the coating film over the tool attaching faces.

Abstract: An end mill body comprises: bottom blades formed at ridgelines where gashes and tip flank faces intersect, the gashes are formed at the tips of chip discharge grooves. At least one of the bottom blades serves as a long bottom blade that extends toward an inner peripheral side longer than the remaining bottom blades. The end mill body also has coolant holes formed between the chip discharge grooves. A coolant hole which is located between a chip discharge groove of a gash and a chip discharge groove located behind the chip discharge groove in a rotational direction is open to the tip clearance face of the long bottom blade. A coolant hole which is located between the chip discharge groove of the gash and a chip discharge groove located in front of the chip discharge groove in the rotational direction is open to the gash of the long bottom blade.

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 ball end mill comprises a gash provided at a front end portion of a main end mill body rotated about an axis; and at least one cutting edge which has a rotational trajectory around the axis that forms a convex hemispherical shape having a center on the axis. The cutting edge is formed at a peripheral edge portion of a wall surface of the gash. A difference between a first and second included angles is within ±7°, where the first included angle is formed between the axis and a straight line connecting the center with a cutting edge position at which a depth of the gash is maximal in a cross-section orthogonal to the cutting edge, and the second included angle is formed between the axis and a straight line connecting the center with a cutting edge position at which a rake angle of the cutting edge is maximal.

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: An end mill comprises: a main body with two coolant holes; three chip discharge grooves formed at an outer periphery of a tip portion of the main body; gashes formed at the tip portions of the three chip discharge grooves; and three end cutting edges formed at intersecting ridgeline portions between tip flanks and wall surfaces facing an end mill rotation direction of the gashes. One end cutting edge is long and extends across the axis line at a tip of the main body. Inner peripheral ends of two remaining end cutting edges are disposed at intervals from the axis line. Two coolant holes are drilled toward a tip side in a direction of the axis line. A first coolant hole opens at the tip flank of the long edge, and a second coolant hole opens at a gash of one of the two remaining end cutting edges.