A milling cutting insert has a substantially triangular shape. The cutting insert contains a top side, an underside, and circumferential side surfaces extending between the top side and the underside. Cutting edges are formed at the transition of the circumferential side surfaces to the top side and/or the underside. On the circumferential side surfaces at least two discrete planar abutment surfaces are formed for positioning the cutting insert in a tool holder. The at least two discrete planar abutment surfaces are inclined with respect to each other at an outer angle of between 190° and 220° and the abutment surfaces are spaced from each other with respect to the circumferential direction of the cutting insert.

A front and back chamfering rotary milling cutter includes a cutter body including an insert pocket and a star-shaped indexable cutting insert releasably retained in the pocket. The cutting insert has star-shaped upper and lower surfaces connected by a peripheral surface intersecting each of the upper and lower surfaces. The cutting insert includes a plurality of circumferentially alternating inner and outer corner portions. A cutting portion is defined by each outer corner portion together with an adjacent first inner corner portion rotationally forward thereof and an adjacent second inner corner portion located rotationally rearward thereof. Each cutting portion includes a front chamfering cutting edge extending from the outer corner portion to the first inner corner portion and a back chamfering cutting edge extending from the outer corner portion to the second inner corner portion.

A cutting tool for face milling includes insert pockets for the fixing of cutting insert. The cutting inserts can be fixed in the insert pockets, wherein the cutting inserts and insert pockets are designed such that, when the cutting inserts are fixed within the corresponding insert pocket, each cutting insert presents: a primary and a secondary cutting edge. The intersection between the primary and the secondary cutting edge of one cutting insert being axially inwardly and radially outwardly offset from the intersection between the primary and the secondary cutting edge of another cutting insert. A lead angle defined between the primary and the secondary cutting edges is less than 30°.

A cutting insert of the present invention comprises: an upper surface and a lower surface; first and second lateral surfaces; first and second cutting edge parts; and corner cutting edges, wherein the first cutting edge part includes: a first main cutting edge for forming one end at a portion spaced farthest away from the corner cutting edge; a first sub-cutting edge connected to the corner cutting edge; and a first auxiliary cutting edge for connecting the first main cutting edge and the first sub-cutting edge so as to form a step between the same, and the first sub-cutting edge and the corner cutting edge form one straight line when viewed toward the first lateral surface, and are inclined upward in the direction opposite to the direction toward the lower surface while gradually going in the direction toward the second cutting edge part.

A cutting insert includes an end cutting edge, a first major cutting edge, and a second major cutting edge. The height of the end cutting edge relative to an imaginary plane orthogonal to a central axis of a through-hole is fixed. The height of the first major cutting edge relative to the imaginary plane increases, when viewed from a side, moving away from the end cutting edge. The height of the second major cutting edge relative to the imaginary plane decreases, when viewed from a side, moving away from the first major cutting edge. When viewed from a side, the angle of inclination, relative to the imaginary plane, of an imaginary line connecting both ends of the second major cutting edge is greater than an angle of inclination, relative to the imaginary plane, of an imaginary line connecting both ends of the first major cutting edge.

A double-sided, trigon cutting insert has three three major cutting edges formed at an intersection between a first planar side surface portion and first and second surfaces, and three minor cutting edges formed at an intersection between a second planar side surface portion and first and second surfaces. A planar rake surface extends radially inward and downward from each major cutting edge, and a rounded rake surface extends radially inward and downward from each minor cutting edge. An insert-receiving pocket of a cutting tool includes a planar bottom support surface, a first planar side support surface, a second planar side support surface, and a third planar side support surface. Each rounded rake surface is formed with a radius, R, that causes only a high point of each minor cutting edge to contact a workpiece during a machining operation.

A cutting insert (1) has a first end surface (2); a second end surface (3) opposing the first end surface; and a peripheral side surface (4) connecting the first and second end surfaces. A cutting edge (6) extends along an intersecting edge between the first end surface and the peripheral side surface. A land (20) is formed in the first end surface and extends along the cutting edge. At least one groove (18) is formed in the peripheral side surface, each groove forming an opening in the first end surface and separating the cutting edge into a plurality of portions. In a plan view of the first end surface, a portion of the land adjacent to an end area (S) of the groove, has a greater width than a width of a portion of the land which is distant from the groove.

A cutting insert has an upper surface, a lower surface, a side surface connected to each of the upper surface and the lower surface, and a cutting edge having sequentially a corner cutting edge, a first straight cutting edge, a second straight cutting edge, and a third straight cutting edge, which are located along an intersection of the upper surface and the side surface and intersect one another at an obtuse angle. The upper surface has a first inclined surface extending along the first straight cutting edge, a second inclined surface extending along the second straight cutting edge, and a third inclined surface extending along the third straight cutting edge. An inclination angle of the second inclined surface with respect to the lower surface is larger than an inclination angle of each of the first inclined surface and the third inclined surface with respect to the lower surface.

A cutting insert may include a base including a first surface, a second surface and a lateral surface. The first surface may include a first corner, a second corner and a first side. The first side may include a first portion, a second portion, a third portion and a fourth portion in this order in a direction from the first corner to the second corner. An imaginary straight line being in contact with the first portion may be a reference line in a front view of the first surface. Inclination angles of the first portion, the second portion, the third portion and the fourth portion relative to the reference line may be respectively a first angle, a second angle, a third angle and a fourth angle. The third angle may be smaller than each of the second angle and the fourth angle.

A cutting insert has a plate shape centered on an insert center axis. The cutting insert includes a front surface and a back surface facing an insert axial direction, an outer peripheral surface facing outward in an insert radial direction, and a cutting edge at an intersecting ridge line between the front surface and the outer peripheral surface. The back surface has a flat shape perpendicular to the insert center axis. The outer peripheral surface includes a flank surface coupled. The flank surface is inclined inward in the insert radial direction as extending in the insert axial direction from the front surface side to the back surface side. The front surface includes a rake surface. The rake surface is inclined from a back surface side to a front surface side in the insert axial direction as extending inward in the insert radial direction from the cutting edge.