An indexable tangential cutting insert for a milling tool includes two opposing side surfaces and four identical lateral surfaces extending between the side surfaces. Each lateral surface of the insert is provided with a support surface configured to be supported by, on one hand, a corresponding support face of a pocket of a tool body providing an axial support to the insert in two of eight index positions and, on the other, a corresponding support face of the pocket providing a tangential support to the insert in two other of said eight index positions. Each lateral surface of the insert is provided with a single second support surface being concave as seen in a direction perpendicular to said side surfaces and extending diagonally across the lateral surface.

In a circular cutting insert of the present invention, the upper side surface and the lower side surface each include: a plurality of planar restraining faces which are disposed sequentially in a circumferential direction of the upper side surface and the lower side surface so as to interpose a joint portion between each of the planar restraining faces and each have a side disposed on the side surface-intermediate line (N); and a plurality of antivibration restraining faces which are each disposed between two planar restraining faces adjacent through the joint portion and each include an inclined face, and the restraining faces of the lower side surface are disposed so as to be shifted with respect to the restraining faces of the upper side surface by a predetermined angle () around a central axis of a screw insertion hole.

A compression milling cutter includes a shank and a front cutting portion that terminates at a leading end of the milling cutter. The front cutting portion has a first circumferential row of one or more insert receiving pockets proximate a leading end of the milling cutter, and a second circumferential row of one or more insert receiving pockets, each insert receiving pocket configured to receive a respective indexable cutting insert. The cutting insert mounted in the first circumferential row has a positive axial rake angle, A, and the indexable cutting insert mounted in an insert pocket of the second circumferential row has a negative axial rake angle, B. Because of the different axial rake angles, chips generated during a machining operation flow in opposite directions, thereby creating a compression zone disposed between the first and second circumferential rows. This compression zone replicates the cutting action of a solid end mill, particularly when machining fiber reinforced plastic materials.

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

A cutting insert has first and second end surfaces, a peripheral side surface, a reference central axis A perpendicular to and passing through the two surfaces, and a cutting edge having at least one circular-arc-shaped cutting edge. A contact surface portion is formed in the second end surface. The arc-shaped cutting edge is part of virtual circle having a center E which is spaced apart from the central axis A. A longitudinal plane B includes the central axis A and the center E; a median plane C perpendicular to the central axis A passes midway between the two end surfaces; and a virtual plane D perpendicular to both the longitudinal plane B and the median plane C, intersects the circular-arc-shaped cutting edge and traverses the contact surface portion. In a cross-section along the virtual plane D, the contact surface portion is inclined relative to the median plane C.

A cutting insert has a first (top) end surface, a second (bottom) end surface, a peripheral side surface connecting the top and bottom end surfaces, and a mounting hole having a central axis O which penetrates the top and bottom end surfaces. Cutting edges are formed on an intersecting edge between the first end surface and the peripheral side surface. The second end surface has an inclined part. When a virtual plane substantially perpendicular to the axis O and passing through any point of the cutting edges is defined, the inclined part is inclined so as to be more distant from the virtual plane, heading from the peripheral side surface to the axis O. A projected part projected in a direction along the axis O is formed in an area around the mounting hole in the inclined part. This reinforces the strength of the mounting hole.

The cutting edge has: a corner cutting edge; a flat cutting edge continuous to a first end portion of the corner cutting edge; and a main cutting edge continuous to a second end portion of the corner cutting edge opposite to the first end portion of the corner cutting edge. The rake face has: a first rising surface portion; and a first rake face portion continuous to the first rising surface portion and located opposite to the corner cutting edge when viewed from the first rising surface portion. When viewed in a direction perpendicular to the reference surface, the first boundary includes a first line segment extending, from one of the flat cutting edge and the corner cutting edge, in a direction crossing a straight line extending along the main cutting edge.

A cutting tool holder (10) configured for mounting thereon a cutting insert (30) to form a cutting tool (1); the cutting insert (30) has a top face (32T), a bottom face (32B), at least one side wall (32S) extending between the top face (32T) and the bottom face (32B), and an insert bore (35) extending between the top face (32T) and the bottom face (32B); the cutting tool holder (10) comprises a body (12) and a fastening member (50), the body (12) comprising an insert seat (20) having a base surface (22) and being configured for receiving therein the cutting insert (30); and a seat bore (25) having an open end at the base surface (22); the fastening member (50) defines a fastening member axis (XFM) and comprises and shank portion (52) and a head portion (51) extending therealong; the shank portion (52) is configured for being received within the seat bore (25); and the head portion (51) comprises a first clamping region, and a second clamping region axially spaced therefrom and disposed between the shank portion (52) and the first clamping region; the fastening member (50) is configured for assuming a mounting position, in which the fastening member (50) remains in engagement with the seat bore (25) in the mounting position while allowing positioning of the cutting insert (30) into the insert seat (20), and a securing position in which the first and second clamping regions are disposed so as to engage two axially-spaced regions of the cutting insert (30) thereby securing it in the insert seat (20).

An indexable milling or drilling insert having a 180-degree rotational symmetry about each of the first, second and third axes (X, Y, Z) of a three-dimensional euclidean space. The insert has opposite first and second main surfaces and a peripheral surface extending therebetween. Each main surface has a main abutment surface and at least two rake surfaces. The insert has a through clamping bore which extends along the third axis and opens out to the main surfaces. The peripheral surface has two opposite front surfaces connected to two opposite side surfaces. Each front surface has a pair of outward abutment surfaces and each side surface has a pair of at least partially planar inward abutment surfaces. Each pair of outward abutment surfaces converge outwardly away from the third axis and each pair of inward abutment surfaces converge inwardly towards the third axis.

A single-sided three-way indexable milling insert for 90 shoulder milling operations, includes a positive basic shape, a rake surface, a peripheral surface including side abutment surfaces, a base bearing surface and a screw hole connecting the rake and base bearing surfaces. The insert has three main cutting edges which lie along an imaginary equilateral triangle. A material volume V.sub.F of the cutting insert and a void volume V.sub.S of the insert's screw hole fulfill the condition V.sub.S/V.sub.F0.30.