A cutting insert according to an aspect includes a base portion and a cutting portion. The cutting portion includes a front end surface, an top surface, a first lateral surface, a second lateral surface, a front cutting edge, and a lateral cutting edge. The front cutting edge includes a first cutting edge and a second cutting edge, and a radius of curvature of the first cutting edge is greater than a radius of curvature of the second cutting edge.

A cutting insert includes an upper surface and a cutting edge. The upper surface includes a first surface and a second surface which is located further inward than the first surface. The cutting edge includes a first cutting edge and a second cutting edge. The first surface includes a first region along the first cutting edge, a second region adjacent to the first region, and a third region which is adjacent to the second region and along the second cutting edge. The second surface includes a fourth region, a fifth region and a sixth region. A width of the second region is smaller than each of a width of the first region and a width of the third region. An inclination angle of the fifth region is smaller than each of an inclination angle of the fourth region and an inclination angle of the sixth region.

A cutting insert is provided, comprising a top surface, a bottom surface, a plurality of side surfaces spanning therebetween, and a cutting edge formed at an intersection of the side surface and a forwardly-disposed portion of the top the surface. It further comprises a cooling cavity projecting into the insert, a top end thereof being disposed further forwardly than an open bottom end thereof. The cooling cavity defines at least one molding axis such that a solid element having the shape of the cooling cavity and completely inserted therein may be retracted intact therefrom along a linear path parallel to the molding axis. A circumscribing portion is formed on the side surfaces encircling the cutting insert. The circumscribing portion is formed parallel to the molding axis and has a non-zero height along its entire extent. The cutting insert does not extend beyond the circumscribing portion.

A cutting insert may include an upper surface, a lateral surface, and a cutting edge including a boundary between the upper surface and the lateral surface. The upper surface may include a first rising face that extends upward and a second rising face that is connected to an upper side of the first rising face and extends upward. The first rising face may include a first region that extends along a corner portion and a second region that extends along a side portion. The second rising face may include a third region connected to the first region and a fourth region connected to the second region. An entirety of a boundary between the first region and the third region may be positioned above the cutting edge. A boundary between the second region and the fourth region may include a portion disposed below the cutting edge.

It is intended to allow a wide range including a low region (fine finishing) to a middle region (medium cutting) to be covered with a single insert. A cutting insert includes an upper surface, a lower surface, a peripheral side surface, a cutting edge including a main cutting edge and a corner cutting edge, a corner portion, a projecting portion formed to extend from the corner portion toward a central axis and including a first projection and a second projection, a rake portion, and an inclined portion provided at the cutting edge. The inclined portion has a first inclined portion beginning at an intermediate point in the corner cutting edge, while the rake portion has a shape in which an angular degree of a rake angle gradually increases with distance from the corner portion.

An assembly of a generally rhombus-shaped reversible cutting insert and a support seat. Each end surface of the cutting insert has a corner abutment surface adjacent each nose cutting edge, at least one inner abutment surface on one side of a lateral plane, and at least one inner abutment surface on the opposite side of the lateral plane, and each corner abutment surface is located closer to a median plane than its adjacent nose cutting edge. In each index position of the cutting insert on the support seat, only one corner abutment surface is in operative contact with one of a plurality of protruding supporting members of the support seat, and only the at least one inner abutment surface located on the opposite side of the lateral plane from the operative corner abutment surface is in contact with the at least one remaining supporting member.

A cutting insert is provided, comprising a top surface, a bottom surface, a plurality of side surfaces spanning therebetween, and a cutting edge formed at an intersection of the side surface and a forwardly-disposed portion of the top the surface. It further comprises a cooling cavity projecting into the insert, a top end thereof being disposed further forwardly than an open bottom end thereof. The cooling cavity defines at least one molding axis such that a solid element having the shape of the cooling cavity and completely inserted therein may be retracted intact therefrom along a linear path parallel to the molding axis. A circumscribing portion is formed on the side surfaces encircling the cutting insert. The circumscribing portion is formed parallel to the molding axis and has a non-zero height along its entire extent. The cutting insert does not extend beyond the circumscribing portion.

The present invention provides a cutting tool that can firmly hold four types of cutting inserts by one tool main unit. A cutting insert of a cutting tool 1 has an approximately triangular stereoscopic shape including three corner portions. A tool main unit has a fixing portion that can selectively fix a plurality of types of cutting inserts, including: a negative type cutting insert of which angle of the corner portion exceeds 60°, a positive type cutting insert of which angle of the corner portion exceeds 60°; a negative type cutting insert of which angle of the corner portion is less than 60°; and a positive type cutting insert of which angle of the corner portion is less than 60°. The fixing portion has a bottom face that contacts with a bottom face of the cutting insert, and a side wall face that contacts with a side face of the cutting insert. A portion, which contacts with the cutting insert, of the side wall face of the fixing portion differs depending on the type of the cutting insert.

Inclined surfaces are formed on a rake face and a recessed groove is formed in the central portion between the inclined surfaces. A groove width of the recessed groove gradually increases from the position of the end cutting edge toward the rear, then gradually decreases such that the recessed groove has a narrowest portion at a position P2 forward of the position P3 of an upper end of a breaker wall and rearward of a positive rake angle rear end position P1, and then gradually increases toward the rear up to the position P3 of the upper end of the breaker wall. The dimensional relation W1<W2<W3 holds, where W1 is the groove width at the end cutting edge, W2 is the groove width at the narrowest portion, and W3 is the groove width at the position P3 of the upper end of the breaker wall.

An indexable cutting insert for a cutting tool for material processing machines has a first axis of symmetry, at least one fastening bore passing through the indexable cutting insert parallel or coaxially to this first axis, two groups of main cutting edges, secondary cutting edges and cutting corners having a second axis of symmetry rotationally symmetrically opposite one another. At least the main cutting edges enclose an acute cutting edge angle with a plane oriented orthogonally to the first axis of symmetry. A cutting insert holder holds and fixes an indexable cutting insert. A recess for receiving the indexable cutting insert is on an elongated base body with polygonal cross-section. A support surface for supporting the indexable cutting insert is rotated about the base-body longitudinal axis and tilted about a second axis, a line of intersection between the rotated support surface and a plane perpendicular to the longitudinal axis.