A turning tool cutting insert having an insert face with a rake face includes a primary land extending along a first cutting edge. The primary land includes a first primary land portion adjacent a linear edge portion, and a second primary land portion adjacent a central portion of the corner edge portion. The first primary land portion differs from the second primary land portion. A transitional primary land portion adjoins the first primary land portion and the second primary land portion, and forms a transition between the first primary land portion and the second primary land portion. The transitional primary land portion is arranged only adjacent an outer portion of the corner edge portion. Further, a turning tool including a turning tool cutting insert is disclosed.

A method to form a surface on a metal work piece includes providing a turning insert that has a nose angle formed between first and second cutting edges less than or equal to 85°; providing a turning tool having a tool body with an insert seat in which the turning insert is mountable; arranging the orientation of the second cutting edge such that it forms a back clearance angle of more than 90° in a feed direction; rotating the metal work piece around a rotational axis in a first direction; moving the turning insert in a direction parallel to or at an angle less than 45° relative to the rotational axis; and setting the longitudinal axis of the tool body at an angle greater than zero but less than or equal to 90° relative to the rotational axis of the metal work piece.

A turning insert includes a top surface, an opposite bottom surface and a reference plane located parallel to and between the top surface and the bottom surface. A nose portion has a convex nose cutting edge, a first cutting edge and a second cutting edge. The nose cutting edge connects the first and second cutting edges. The first and second cutting edges form a nose angle (α) of 71-85° relative to each other. The nose portion includes a third convex cutting edge adjacent to the first cutting edge and a fourth cutting edge adjacent to the third convex cutting edge. The fourth cutting edge forms an angle (β) of 10-30° relative to a bisector. The distance from at least a portion of the fourth cutting edge to the reference plane increases as the distance from the nose cutting edge increases.

A cutting edge includes a nose portion, a first cutting edge portion, and a second cutting edge portion. When a boundary between a first inclined portion and a first breaker portion, a boundary between a first step surface and a second breaker portion, a boundary between a second inclined portion and a third breaker portion, and a boundary between a second step surface and a fourth breaker portion are a first position, a second position, a third position, and a fourth position, respectively, the second position is higher than the first position and the fourth position is higher than the third position in a direction perpendicular to the seating surface, and a distance between the first position and the third position is greater than a distance between the second position and the fourth position in a direction parallel to the seating surface.

A peeling plate has upper and lower sides, lateral faces extending between the upper and lower sides, and primary and secondary cutting edges at the transition from the lateral faces to the upper side. The peeling plate in a plan view of the upper side has the shape of a substantially regular n-gon, n being five or six, and n lateral edges lying between the n lateral faces. A primary cutting edge and a secondary cutting edge are formed at the transition from at least one lateral face to the upper surface, wherein active primary cutting edges and active secondary cutting edges are spaced apart from a lateral edge. The lateral edge at the transition to the upper side forming an active cutting corner to the respective active primary cutting edge and active secondary cutting edge.

The throwaway insert includes a base and a cutting edge member. The cutting edge member includes a rake face, a flank face, a first connecting face, a second connecting face, and a first ridgeline serving as a cutting edge. The rake face includes a main surface and a first chamfer provided at an edge tip portion of the cutting edge member, the edge tip portion including an extreme tip portion of the cutting edge member. In a plan view from an upper surface of the base, the flank face, the first connecting face, and the second connecting face are located external to the base. The first chamfer is inclined relative to the main surface so as to increase a thickness of the cutting edge member as the first chamfer is closer to the main surface.

A cutting insert may include a first surface, a second surface, a third surface, and a land surface. The first surface may include a first corner, a first side, and a second side. The land surface may be inclined relative to the first surface and the third surface. The land surface may include a first land surface connecting to the first corner. An imaginary flat surface orthogonal to a central axis connecting a center of the first surface and a center of the second surface may be a reference plane, a first inclination angle of a part of the first land surface which connects to a midportion of the first corner may be larger than a second inclination angle of a part of the first land surface which connects to an end portion at a side of the first side of the first corner.

A turning insert has two opposite main surfaces and a peripheral surface which extends therebetween and has N side surfaces, where 2<N<9. The insert has mirror symmetry about a mid-plane and 360/N degree rotational symmetry about a central axis perpendicular to the mid-plane. The insert has two main edges which each have N main cutting edges and N corner cutting edges. Each main cutting edge has two raised edge portions and a lowered edge portion. Each main surface has N main rake surfaces and N corner rake surfaces. Each main surface further has at least N convex island protrusions and N at least partially convex peninsula protrusions, any and all island protrusions associated with a given main rake surface being located between two adjacent peninsula protrusions, each pair of adjacent peninsula protrusions having at least one island protrusion located therebetween.

A turning insert includes a top surface, an opposite bottom surface, a reference plane located parallel to and between the top surface and the bottom surface, and a center axis extending perpendicular to the reference plane and intersecting the reference plane (RP), the top surface and the bottom surface. Side surfaces connect the top surface and the bottom surface. Three nose portions are formed symmetrically relative to the center axis. Each nose portion includes a first cutting edge, a second cutting edge and a convex nose cutting edge connecting the first) and second cutting edges. In a top view the first and second cutting edges on the same nose portion form a nose angle of 25-50° relative to each other. The distance from the first cutting edge to the reference plane varies in such a way that that this distance is decreasing at increasing distance from the nose cutting edge.

There is provided a cutting insert used for both drilling and turning. The cutting insert includes an insert main body having a front surface and a rear surface, the outline shapes of which are parallelogram shapes, peripheral side surfaces disposed on four sides of the insert main body, cutting edges provided on respective intersecting ridge lines between the front surface and the peripheral side surface and between the rear surface and the peripheral side surface of the insert main body, and a hole provided in the insert main body to incline with respect to the front surface and the rear surface, the hole being usable for attachment.