A cutting insert has: first sub cutting edges at positions corresponding to first corner portions of a polygonal top surface; second sub cutting edges at positions corresponding to second corner portions; and main cutting edges on side portions. In a side view, each of the main cutting edges has a first cutting edge adjacent to the first sub cutting edge, a second cutting edge adjacent to the second sub cutting edge, and a third cutting edge between the first cutting edge and the second cutting edge. Each of the main cutting edges inclines such that the height thereof decreases from a portion adjacent to the first sub cutting edge to a portion adjacent to the second sub cutting edge. An inclination angle of the third cutting edge is greater than inclination angles of the first cutting edge and the second cutting edge.

The present invention relates to a tool body provided with at least one insert seat. The insert seat includes a bottom wall surface and a side wall surface. The side wall surface includes a first side wall surface and a second side wall surface. The first side wall surface includes at least two surface portions. The first surface portion is a curved surface having a recessed shape recessed toward a base end of the tool body, and the second surface portion is a curved surface having a recessed shape recessed toward the base end of the tool body, with a greater curvature radius than that of the first surface portion, or a flat surface. The two surface portions both come into contact with a cutting insert.

The present invention discloses a vertically-mounted milling cutter insert and a multitooth milling cutter, wherein the vertically-mounted milling cutter insert comprises a insert base and a cutter tip unit, the insert base is set with a mounting hole for mounting the vertically-mounted milling cutter insert onto the milling cutter wheel, and the cutter tip unit is mounted on the insert base, and the cutter tip unit has a double-cutter tip structure. In the invention, the vertically-mounted milling cutter insert is positioned via the fitting between a bent-plane structure in the vertically-mounted milling cutter insert and a positioning structure in the milling cutter wheel, and the bent-plane structure will not be abraded in use. Because the bent-plane structure will not be abraded, reliable positioning may be guaranteed when two cutter tips are used.

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.

A cutting insert (1) comprises: a first end surface (2) and a second end surface (3) which are opposed to each other; a peripheral side surface (4) which extends so as to connect the first end surface (2) and the second end surface (3); a first cutting edge (5a) which is arranged in an intersecting edge between the first end surface (2) and the peripheral side surface (4); and a second cutting edge (5b) which is arranged in an intersecting edge between the second end surface (3) and the peripheral side surface (4). The peripheral side surface (4) includes a first flank (4a1) which is connected to the first cutting edge (5a) and an intermediate peripheral side surface portion (4b) which is arranged closer to the second end surface (3) than the first flank (4a1). The first flank (4a1) extends in a direction perpendicular to the first end surface (2). The intermediate peripheral side surface portion (4b) protrudes outward from the first flank (4a1).

An indexable cutting insert has a first corner edge forming a front tip of a cutting edge portion configured to project furthest in the direction of an axis of rotation of an end mill tool receiving the insert. A major cutting edge is descending to come closer to the lower surface of the insert along its extension away from the first corner edge. The minor cutting edge extends from the first corner edge while descending from a point of the cutting edge portion most distant to the lower surface all the way to an inner corner of the insert and has a length of 80%-95% of the length of the major cutting edge including a second corner edge in a side elevation view of the cutting insert.

The technical objective of the present invention is to provide a cutting insert that can minimize a phenomenon in which the cutting insert is lifted up from a seat surface of a cutting tool while a cutting process is being performed, and can increase an area by which the cutting insert is fastened to the cutting tool. To this end, the cutting insert of the present invention comprises: a principal surface; a fastening surface opposite to the principal surface, the fastening surface being placed on the seat surface of the cutting tool; and a screw passage hole formed through each of central portions of the principal and fastening surfaces, wherein a screw is fastened to the cutting tool through the screw passage hole; and first and second long grooves extending across the fastening surface, wherein each of the first and second long grooves includes: a proximal sidewall adjoining a first adjacent fastening portion of the fastening surface and making an acute angle with the first adjacent fastening portion; a distal sidewall adjoining a second adjacent fastening portion of the fastening surface and making an angle with the second adjacent fastening portion; and a ceiling wall connecting the proximal and distal sidewalls, wherein the proximal sidewall is located closer to the screw passage hole than the distal sidewall is located to the screw passage hole.

A toolholder includes a bottom abutment surface, a projection extending upwardly from the bottom abutment surface, the projection including an internally threaded opening, having a central axis that is offset from a central axis of the projection in a first direction, and a clamping screw having external threads for mating with threads of the internally threaded opening and a head having a bottom clamping surface shaped as a truncated cone for contacting an insert clamping surface and urging an insert substantially in a first direction when the clamping screw is tightened relative to the toolholder and the insert. The toolholder also includes at least one abutment member extending from a side wall of the projection in a radial direction, each abutment member having an abutment point, at least which is closer to the central axis of the projection than to the central axis of the internally threaded opening.

A tool and a cutting insert for chip removing machining includes a tool body with an insert seat, a cutting insert mounted in the insert seat, and a fastening member. The cutting insert includes a first locking member extending in an area located outside of a central axis of the cutting insert. A second locking member configured to engage with the first locking member is provided in the insert seat. The fastening member extends through a through-hole and bears on a lower contact region of the cutting insert to press the cutting insert against a top support member provided rotationally ahead of the insert seat so that the second and first locking members lock with each other and form a radial support for the cutting insert, and on the other hand it presses an axial support region in the side surface of the cutting insert against an axial contact surface provided in the insert seat.

A cutting tool includes a cutting insert having an anti-rotation stopping indent formed in a transition between a bottom surface and a side surface thereof and includes a first stop surface. The insert seat has at least one anti-rotation stop, which protrudes with respect to a side wall of the insert seat and includes a second stop surface. The anti-rotation stop is arranged to inhibit rotation of the cutting insert in the insert seat by contact between the first and second stop surfaces. The second stop surface is completely located within the anti-rotation stopping indent when the cutting insert is mounted. As seen in a section perpendicular to a common central axis, an angle of less than 180? is formed between a tangent to the second stop surface and a tangent to the first duct at a transition between the two.