A cutting insert includes a top face, a bottom face and a plurality of side walls extending between the top face and the bottom face. A peripheral cutting edge is defined at the juncture of each side wall and the top face. Each cutting edge includes a linear cutting edge portion and a concave cutting edge portion that curves inwardly in a plane that is perpendicular to a plane containing a central axis of the cutting insert. A radiused corner portion connects two adjacent cutting edges. Each linear cutting edge portion extends from one radiused corner portion to the concave cutting edge portion and the concave cutting edge portion extends from the linear cutting edge portion to another radiused corner portion.

A cutting insert (1) includes a top surface (6), a side surface, a rake face (10) on the top surface (6), a front flank face (11) and a lateral flank face (12), a cutting edge (9) including a front cutting edge (13), and a lateral cutting edge (14), a breaker groove (15) adjacent to the front cutting edge (13) and the lateral cutting edge (14), and a rake face end (20). The breaker groove (15) includes a descending surface (16) and an ascending surface (17). The ascending surface (17) includes a front wall surface (21) and a lateral wall surface (22) on the side of the front cutting edge (13) and the side of the lateral cutting edge (14). An opening angle (1) of the front wall surface (21) is greater than an opening angle (2) of the lateral wall surface (22) in the top surface (6) view.

A double-sided cutting insert for a drilling tool includes a top side, a bottom side, and at least one side surface interconnecting the top side and the bottom side and forming at least one cutting edge. The top side and the bottom side comprise a different external profile and chip groove geometry and an identical inscribed circle, and each of the top side and the bottom side comprises four indexable cutting edges.

A cutting tool includes an upper surface, a flank, and a cutting edge formed on an edge between the upper surface and the flank, the cutting tool having a shape extending in a longitudinal direction along a longitudinal reference axis from a base end part to a leading end part, the cutting tool having the cutting edge member at the leading end part, in which the cutting tool is provided with a chip discharge groove that is constituted by a wall surface at least part of which is curved and at least part of which is located at a position higher than the cutting edge, in which the chip discharge groove has a shape extending in a direction different from an axial direction of the longitudinal reference axis.

Disclosed is a cutting insert having a generally polygonal primary body having a primary body base connected to an opposing and similarly-shaped body face through a plurality of primary flank portions extending there between. The cutting insert further includes at least one cutting protrusion extending away from at least one of the primary flank portions, and merging therewith. The cutting protrusion includes a rake face coplanar and extending away from the adjacent primary flank portions, and an edge portion extended towards a cutting flank portion. The cutting protrusion further includes a tip flat extending between a rake front from a protrusion tip towards a rake root portion, adjacent one of the primary flank portions.