Abstract: In the radius end mill, main gash faces has an angle of inclination with respect to an axis that is smaller than a twist angle of chip discharge flutes. The main gash faces are formed on inner circumferential sides of distal end portions of wall surfaces that face in a tool rotation direction of helically twisted chip discharge flutes, which is formed on an outer circumference of a distal end portion of a tool body that is rotated around the axis. End cutting edges are formed on a distal end of the main gash faces. Sub gash faces has an angle of inclination with respect to the axis that is greater than that of the main gash faces. The sub gash faces are formed on an outer circumferential side of the main gash faces such that they extend away via step portions from the main gash faces.

Abstract: In the radius end mill, main gash faces has an angle of inclination with respect to an axis that is smaller than a twist angle of chip discharge flutes. The main gash faces are formed on inner circumferential sides of distal end portions of wall surfaces that face in a tool rotation direction of helically twisted chip discharge flutes, which is formed on an outer circumference of a distal end portion of a tool body that is rotated around the axis. End cutting edges are formed on a distal end of the main gash faces. Sub gash faces has an angle of inclination with respect to the axis that is greater than that of the main gash faces. The sub gash faces are formed on an outer circumferential side of the main gash faces such that they extend away via step portions from the main gash faces.

Abstract: In the radius end mill, main gash faces has an angle of inclination with respect to an axis that is smaller than a twist angle of chip discharge flutes. The main gash faces are formed on inner circumferential sides of distal end portions of wall surfaces that face in a tool rotation direction of helically twisted chip discharge flutes, which is formed on an outer circumference of a distal end portion of a tool body that is rotated around the axis. End cutting edges are formed on a distal end of the main gash faces. Sub gash faces has an angle of inclination with respect to the axis that is greater than that of the main gash faces. The sub gash faces are formed on an outer circumferential side of the main gash faces such that they extend away via step portions from the main gash faces.

Abstract: A ball nose end mill includes a tool body and a throwaway insert mountable on the tool body. The throwaway insert includes a bottom face as a mounting face, an upper face on an opposite side from the bottom face, a side face formed between the bottom face and the upper face, and a cutting edge formed along an intersecting ridge between the upper face and the side face in a substantially arc shape such that the rotational trace of the cutting edge when the throwaway insert is attached to the tool body in use substantially forms a partial spherical surface. An undulating portion, which is formed by alternately arranged concave portions and convex portions, is provided on the upper face so as to intersect the cutting edge. At least one of the concave portions is formed as a deep-concave portion which has a greater depth than that of the others.

Abstract: In the radius end mill, main gash faces has an angle of inclination with respect to an axis that is smaller than a twist angle of chip discharge flutes. The main gash faces are formed on inner circumferential sides of distal end portions of wall surfaces that face in a tool rotation direction of helically twisted chip discharge flutes, which is formed on an outer circumference of a distal end portion of a tool body that is rotated around the axis. End cutting edges are formed on a distal end of the main gash faces. Sub gash faces has an angle of inclination with respect to the axis that is greater than that of the main gash faces. The sub gash faces are formed on an outer circumferential side of the main gash faces such that they extend away via step portions from the main gash faces.

Abstract: A ball nose end mill includes a tool body and a throwaway insert mountable on the tool body. The throwaway insert includes a bottom face as a mounting face, an upper face on an opposite side from the bottom face, a side face formed between the bottom face and the upper face, and a cutting edge formed along an intersecting ridge between the upper face and the side face in a substantially arc shape such that the rotational trace of the cutting edge when the throwaway insert is attached to the tool body in use substantially forms a partial spherical surface. An undulating portion, which is formed by alternately arranged concave portions and convex portions, is provided on the upper face so as to intersect the cutting edge. At least one of the concave portions is formed as a deep-concave portion which has a greater depth than that of the others.

Abstract: A throwaway insert enables reduction in cutting force and improves chip separation ability without sacrificing the strength of cutting edge thereof. An upper face of the throwaway insert is provided with an undulating portion, which is formed by alternately arranged concave portions and convex portions, so as to provide a wavy shape to the cutting edge. The undulating portion comprises four concave portions, i.e., a first deep-concave portion, a first shallow-concave portion, a second deep-concave portion, and a second shallow-concave portion. The first deep-concave portion and the second deep-concave portion are located so that effective cutting region of the cutting edge is divided into three portions having lengths substantially equal to each other, and the second deep-concave portion is made deeper than the first deep-concave portion.

Abstract: A throwaway insert enables reduction in cutting force and improves chip separation ability without sacrificing the strength of cutting edge thereof. An upper face of the throwaway insert is provided with an undulating portion, which is formed by alternately arranged concave portions and convex portions, so as to provide a wavy shape to the cutting edge. The undulating portion comprises four concave portions, i.e., a first deep-concave portion, a first shallow-concave portion, a second deep-concave portion, and a second shallow-concave portion. The first deep-concave portion and the second deep-concave portion are located so that effective cutting region of the cutting edge is divided into three portions having lengths substantially equal to each other, and the second deep-concave portion is made deeper than the first deep-concave portion.

Abstract: The present invention provides an indexable insert which can pare away the chip stably without increase of cutting resistance. With this insert, serrations are formed by arranging a plurality of groove portions and ridge portions alternatingly upon side ridge edge portions of the upper surface, with the exception of sloping surfaces which are formed at both end portions in the longitudinal directions of the upper surface. As a result, the cutting edges exhibit wavy shapes which are made up from this plurality of groove portions and ridge portions over the sloping surface, with the exception of these sloping surfaces. Furthermore, the groove portions and the ridge portions of the serrations are made as curved surfaces. This insert is fitted to a tool main body so that the groove portions and the ridge portions of the serrations extend perpendicular to the rotational axis of the tool.

Abstract: In a mounting mechanism for a pin mirror cutter 22, the cutter body 22 is mounted with its outer periphery inserted into the inner periphery of a cutter mounting portion. an inclined surface of a tapered portion 22 formed on the cutter body and an inclined surface of a tapered portion formed on the cutter mounting portion are in surface-contact with each other, and the diameters of the contact surfaces gradually decrease in the direction of insertion of the cutter body into the cutter mounting portion. Furthermore, these inclined surfaces and are formed by a plurality of flat surfaces so as to form regular octagonal pyramid surfaces.