A reversible cutting insert for milling including opposing and identically or substantially identically top and bottom surfaces interconnected by a continuous peripheral side surface, with a median plane located between the top and bottom surfaces and intersecting the side surface, and an insert axis perpendicular to the median plane about which the cutting insert is indexable. Each top and bottom surface is limited by a circumferential cutting edge intersecting the side surface, the circumferential cutting edge in a top view having the shape of a truncated equilateral triangle. Each circumferential cutting edge includes three analogous sets of cutting edges exhibiting three-fold rotational symmetry about the insert axis. A first cutting edge portion intersects a first support plane.

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 positioning tool is configured for retaining an undersized, bore-less indexable cutting insert. The cutting insert may have a triangular or trigonal shape. The positioning tool has an outwardly facing insert retaining surface which has an elongated shape which corresponds to a shape of a side of the undersized cutting insert. The positioning tool is configured to retain the cutting insert using magnetic force, electrostatic force and/or adhesive force. A milling kit may include such a positioning tool, along with one or more such undersized cutting inserts. The milling kit may optionally also include a milling tool having one or more insert pockets configured to accommodate such cutting inserts, and may further optionally include one or more clamping screws configured to clampingly and externally secure such inserts in the pocket without passing through the inserts.

A rotary cutting tool is provided which, although it has a simple configuration, allows the arrangement of each cutting edge to be easily adjusted. A first cartridge mounting seat has an upper wall surface opposing an outer side surface of a cartridge and further has a first recessed part into which a protrusion is inserted and which comes into contact, at a bottom thereof, with a leading end of the protrusion. A second cartridge mounting seat has an upper wall surface opposing an outer side surface of a cartridge and further has a second recessed part into which a protrusion is inserted and which comes into contact, at a bottom thereof, with a leading end of the protrusion. A depth of the second recessed part is greater than a depth of the first recessed part. An amount of protrusion P of the protrusion is equal to or greater than the depth of the second recessed part.

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.

An indexable cutting insert has opposing upper and lower end surfaces, and a peripheral surface including three side surfaces circumferentially alternating with three corner surfaces. The three side surfaces define an imaginary triangle and an imaginary hexagon. Each corner surface intersects the upper end surface to form an upper corner peripheral edge having a primary cutting edge. In a top view, each triangle side traverses two upper corner peripheral edges, imaginary lines tangential to the end points of each primary cutting edge are either collinear or form an obtuse angle greater than 175 degrees, each primary cutting edge has a primary length greater than half the hexagon side length, and at least one triangle side traverses each primary cutting edge. The insert is removably secured in a rotary cutting tool such that one of the upper corner peripheral edges contains an axially forwardmost point of the insert's upper peripheral edge.

A positioning tool is configured for retaining an undersized, bore-less indexable cutting insert. The cutting insert may have a triangular or trigonal shape. The positioning tool has an outwardly facing insert retaining surface which has an elongated shape which corresponds to a shape of a side of the undersized cutting insert. The positioning tool is configured to retain the cutting insert using magnetic force, electrostatic force and/or adhesive force. A milling kit may include such a positioning tool, along with one or more such undersized cutting inserts. The milling kit may optionally also include a milling tool having one or more insert pockets configured to accommodate such cutting inserts, and may further optionally include one or more clamping screws configured to clampingly and externally secure such inserts in the pocket without passing through the inserts.

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).

A cutting insert has a substantially triangular or square basic shape with a top surface and a base surface that are connected together by lateral flanks. A cutting edge is formed at the transition between at least one flank and the top surface. The cutting edge extends between cutting corners, and the cutting edge has a portion that is convex in side view of a flank. The convex portion of the cutting edge is bounded on both sides by concavely curved portions.

A cutting insert has an insert major body which includes two hexagonal faces facing each other and six side faces arranged around the two hexagonal faces, and is rotationally symmetrical at 120 intervals about an insert center line passing through centers of the two hexagonal faces and inversely symmetrical in front and back with respect to the two hexagonal faces, wherein a major cutting edge and an minor cutting edge are alternately formed in a circumferential direction in the single hexagonal face at twelve intersecting ridgeline portions at which the hexagonal faces and the side faces intersect, the major cutting edge is formed to be located at an intersecting ridgeline portion with one hexagonal face while the minor cutting edge is formed to be located at an intersecting ridgeline portion with the other hexagonal face at a single side face.