Abstract: A drill head includes a first attachment surface attached to a holder, a head tip surface opposite to the first attachment surface in an axial direction along the central axis, and a head outer peripheral surface continuous with the first attachment surface and the head tip surface. The head outer peripheral surface is provided with a first flute and a second flute extending helically about the central axis from the head tip surface to reach the first attachment surface. The first flute and the second flute are symmetric with respect to the central axis. Each of the first flute and the second flute has a first end and a second end that face each other with a space between them in a circumferential direction along a circumference centered on the central axis.

Abstract: A straight line along the second line segment and a straight line along the fourth line segment form an acute angle. The straight line along the second line segment and the straight line along the third line segment form an obtuse angle. The straight line along the first line segment and the straight line along the fourth line segment form an obtuse angle. Each of the third curved portion and the fourth curved portion is larger in radius of curvature than the first curved portion and larger in radius of curvature than the second curved portion. In a direction perpendicular to the bottom surface, a distance between the top surface and the bottom surface is equal to a distance between the cutting edge and the bottom surface, or is shorter than the distance between the cutting edge and the bottom surface.

Abstract: A cutting insert is mountable on a body. The cutting insert includes: a top surface; a bottom surface opposite to the top surface; a side surface contiguous to the top surface and the bottom surface; and a cutting edge formed at a ridgeline between the top surface and the side surface. The side surface has a first surface disposed adjacent to the cutting edge and a second surface contiguous to the first surface. When viewed in a cross sectional view parallel to the bottom surface, the second surface has a first position and a second position that are brought into abutment with the body when mounted on the body. Between the first position and the second position, an imaginary straight line extending through the first position and the second position is separated from the second surface.

Abstract: A cutting insert of the present disclosure includes a top surface, a bottom surface, a side surface, and a corner cutting edge, a first cutting edge, a second cutting edge and a third cutting edge formed at a ridge line formed by the side surface and the top surface. The corner cutting edge has a first end and a second end. The first cutting edge extends from the first end in a first direction. The second cutting edge extends from the second end in a second direction. The third cutting edge extends from the second cutting edge in a third direction. The top surface has a first rake face adjacent to the first cutting edge, a second rake face adjacent to the second cutting edge, and a third rake face adjacent to the third cutting edge.

Abstract: A ridgeline between the top surface and the side surface includes: a nose cutting edge portion having a curved line shape, the nose cutting edge portion having a first end and a second end opposite to the first end; a major cutting edge portion contiguous to the first end; and a wiper cutting edge portion contiguous to the second end. The top surface includes: a first rake face contiguous to the wiper cutting edge portion; a second rake face contiguous to the major cutting edge portion; and a third rake face contiguous to the nose cutting edge portion and contiguous to each of the first rake face and the second rake face. A boundary line between the second rake face and the third rake face is separated from the first end and is contiguous to the major cutting edge portion.

Abstract: The first seating surface is contiguous to each of the front end surface and the outer circumferential surface. The second seating surface is contiguous to the front end surface. The cutting tool body is provided with a recess contiguous to each of the first seating surface, the second seating surface, and the front end surface. When the front end surface is viewed in a direction from the front end surface toward the rear end surface, a length of the recess in a direction perpendicular to a straight line parallel to the central axis and extending along the first seating surface is equal to or longer than three times as long as a length of the recess in a direction perpendicular to the first seating surface and passing through a contact point of the second seating surface, the recess, and the front end surface.

Abstract: A milling tool includes: a body having an outer circumferential surface formed around a central axis; a cutting insert having a rake surface, a flank surface, and a cutting edge formed by a ridgeline of the rake surface and the flank surface; and a screw attaching the cutting insert to the body. The outer circumferential surface has an insert attachment portion. The insert attachment portion is defined by a first seat surface continuing to the outer circumferential surface and a second seat surface continuing to the first seat surface and having a flat portion provided with a screw hole in which the screw is inserted. The cutting edge is formed of a sintered material containing at least one of cubic boron nitride and polycrystalline diamond. In a cross section perpendicular to the central axis, a first angle formed by a first direction and a second direction is an acute angle.

Abstract: A second distance is longer than a first distance and a value obtained by dividing the third distance by the fourth distance is more than or equal to 0.5 and less than or equal to 0.8 when it is assumed that the first distance represents a distance between the cutting edge and the mounting surface in a direction perpendicular to the rake face, the second distance represents a distance between the mounting surface and a boundary portion between the rising portion and the flat portion in the direction perpendicular to the rake face, the third distance represents a distance between the boundary portion and a tip of the cutting edge in a direction parallel to the rake face, and the fourth distance represents a distance between the second discharging opening portion and the tip of the cutting edge in the direction parallel to the rake face.

Abstract: The holder has a first surface and a second surface. The head includes a cutting edge portion and a shank portion. The holder is provided with a first hole and a second hole communicating with the first hole, the first hole extending in a third direction inclined by a second angle relative to a second direction extending from the second surface toward the first surface when viewed in a direction parallel to the axis line. The shank portion has a flat surface portion, and is provided inside the second hole. The fastening portion is provided inside the first hole, and is in contact with the flat surface portion. In a plane perpendicular to the axis line, a third angle between the second direction and a fourth direction perpendicular to the flat surface portion is larger than the second angle. The third angle is less than 90°.

Abstract: A second distance is longer than a first distance and a value obtained by dividing the third distance by the fourth distance is more than or equal to 0.5 and less than or equal to 0.8 when it is assumed that the first distance represents a distance between the cutting edge and the mounting surface in a direction perpendicular to the rake face, the second distance represents a distance between the mounting surface and a boundary portion between the rising portion and the flat portion in the direction perpendicular to the rake face, the third distance represents a distance between the boundary portion and a tip of the cutting edge in a direction parallel to the rake face, and the fourth distance represents a distance between the second discharging opening portion and the tip of the cutting edge in the direction parallel to the rake face.

Abstract: The holder has a first surface and a second surface. The head includes a cutting edge portion and a shank portion. The holder is provided with a first hole and a second hole communicating with the first hole, the first hole extending in a third direction inclined by a second angle relative to a second direction extending from the second surface toward the first surface when viewed in a direction parallel to the axis line. The shank portion has a flat surface portion, and is provided inside the second hole. The fastening portion is provided inside the first hole, and is in contact with the flat surface portion. In a plane perpendicular to the axis line, a third angle between the second direction and a fourth direction perpendicular to the flat surface portion is larger than the second angle. The third angle is less than 90°.

Abstract: A milling tool includes: a body having an outer circumferential surface formed around a central axis; a cutting insert having a rake surface, a flank surface, and a cutting edge formed by a ridgeline of the rake surface and the flank surface; and a screw attaching the cutting insert to the body. The outer circumferential surface has an insert attachment. The insert attachment portion is defined by a first seat surface continuing to the outer circumferential surface and a second seat surface continuing to the first seat surface and having a flat portion provided with a screw hole in which the screw is inserted. The cutting edge is formed of a sintered material containing at least one of cubic boron nitride and polycrystalline diamond. In a cross section perpendicular to the central axis, a first angle formed by a first direction and a second direction is an acute angle.

Abstract: A cutting tool including: a tool body (2) provided with an insert support seat (5) including a major seat surface (5a) that supports a bearing surface of a cutting insert, a plurality of seat side surfaces (5b, 5c) that supports side surfaces of the cutting insert at different positions, and a thinned portion (5d) continuous with the major seat surface and the seat side surfaces; and a cutting insert attached to the insert support seat, wherein a ridge at a position where the major seat surface and the thinned portion intersect, a ridge at a position where the seat side surface and the thinned portion intersect, and a ridge at a position where the thinned portions continuous with each other intersect are each formed of a convex arc curved surface.

Abstract: A cutting tool including: a tool body (2) provided with an insert support seat (5) including a major seat surface (5a) that supports a bearing surface of a cutting insert, a plurality of seat side surfaces (5b, 5c) that supports side surfaces of the cutting insert at different positions, and a thinned portion (5d) continuous with the major seat surface and the seat side surfaces; and a cutting insert attached to the insert support seat, wherein a ridge at a position where the major seat surface and the thinned portion intersect, a ridge at a position where the seat side surface and the thinned portion intersect, and a ridge at a position where the thinned portions continuous with each other intersect are each formed of a convex arc curved surface.

Abstract: A cutting insert includes a first surface and a second surface each of which is polygonal and that face away from each other; a side surface that is continuous with the first surface and a side surface that is continuous with the second surface; a cutting edge formed along each of a ridge where the first surface and the side surface intersect and a ridge where the second surface and the side surface intersect; a bearing surface formed in each of a part the first surface and a part of the second surface adjacent to an insert center, the bearing surfaces disposed parallel to each other; and a recessed portion that separates the side surface that is continuous with the first surface from the side surface that is continuous with the second surface. The cutting edge includes three corner edges, a first cutting edge, and a second cutting edge, the first and second cutting edges being continuous with each other and located between each pair of the corner edges.