A cutting tool having a cutting edge member which forms at least one corner part, wherein a material for the cutting edge member is selected from either diamond, an ultrahigh-pressure sintered body containing cubic boron nitride or a PVD or CVD coating applied to a surface of the ultrahigh-pressure sintered body. At least part of an intersecting edge between an end surface of the cutting edge member and a peripheral side surface thereof is provided with a cutting edge. A chip breaker comprising a breaker wall surface is formed in the end surface of the cutting edge member. The breaker wall surface has at least one projected surface part which bulges outwardly from the cutting tool. As viewed from the end surface, the recessed surface part is arranged so as to be apart from a virtual plane A which is defined so as to divide the corner part into halves.

A turning insert includes a top surface, an opposite bottom surface, and a reference plane located parallel to and between the top and the bottom surfaces. A nose portion includes a convex nose cutting edge, and a first 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 of 71-85° relative to each other. The nose portion has 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 of 10-30° relative to a bisector. The distance from at least a portion of the fourth cutting edge to the reference plane increases at an increasing distance from the nose cutting edge. A second protrusion is arranged between the nose cutting edge and the first protrusion.

Indexable, double-sided turning inserts for turning operations and and a turning tool are provided with cutting edges at alternating corners on opposite sides of the insert. Chipbreaker structures can be provided without interfering with providing large supporting surfaces. When the insert is used in a cutting operation, chips from one of the cutting edges in use are unlikely to damage cutting edges that are not in use but are on adjacent corners.

A cutting insert includes a base body and a coating layer, and also includes a rake surface, a flank surface, and a cutting edge located along an intersecting ridge therebetween. The rake surface includes an outer peripheral part and a middle part protruded relative to the outer peripheral part. The middle part includes a constraining surface. The outer peripheral part includes a first breaker part, a second breaker part, and the third breaker part adjacent to the constraining surface. The constraining surface is configured by the base body and the coating layer does not exist at the constraining surface. A skewness Rsk of a roughness curve at the constraining surface is −1.5 μm to −0.5 μm. A skewness Rsk at the third breaker part is −0.2 μm or less. The skewness Rsk at the constraining surface is smaller than the skewness Rsk at the third breaker part.

A ridgeline between the top surface and the side surface includes: a nose cutting edge portion having a curved line shape, the nose cutting edge portion having a first end and a second end opposite to the first end; a major cutting edge portion contiguous to the first end; and a wiper cutting edge portion contiguous to the second end. The top surface includes: a first rake face contiguous to the wiper cutting edge portion; a second rake face contiguous to the major cutting edge portion; and a third rake face contiguous to the nose cutting edge portion and contiguous to each of the first rake face and the second rake face. A boundary line between the second rake face and the third rake face is separated from the first end and is contiguous to the major cutting edge portion.

Cutting insert for a tool for machining. The cutting insert is particularly suitable for grooving tools for grooving turning. The cutting insert has a chip breaker geometry in its cutting region, which enables both machining of full cuts and machining of partial cuts as well as machining of webs. In particular, due to the shape of a chip cavity provided in the cutting region and due to the presence of a negative chamfer, very short chips can be produced in all three machining variants, so that a high level of process reliability is ensured and long tool lives are made possible.

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 tool includes a tool body, insert seat and a turning insert. The turning insert has a top surface and an opposite bottom surface, a reference plane between the top and bottom surfaces, and a center axis intersecting the top and bottom surfaces. A circular cutting edge of the insert is concentric in relation to the center axis. The bottom surface includes a set of radial grooves and a set of flat surfaces. The flat surfaces extend in a plane parallel to the reference plane. The insert seat includes a bottom surface and a rear surface. The bottom surface of the insert seat has a first ridge and a support surface, wherein at least one of the flat surfaces of the turning insert is in contact with the support surface. A cross-section of the first ridge is smaller than a corresponding cross section of one of the radial grooves.

Chip discharge during high-feed machining and low-feed machining particularly in a high-depth-of-cut state or the like is improved so as to provide adaptability to a wide range of cutting conditions during low depth and high depth cutting and during low-feed and high-feed machining and allow so-called freedom of feed during cutting to be improved. A cutting insert includes a cutting edge body and a substrate to which the cutting edge body is joined. The cutting edge body has a prismatic shape having a longitudinal direction and a lateral direction perpendicular to the longitudinal direction and includes a cutting edge formed on an intersecting edge between a peripheral side surface and an upper surface of the cutting edge body having the prismatic shape and a recessed part formed at a position on the upper surface of the cutting edge body which is more distant from the intersecting edge than from the cutting edge. The substrate has a projected part upwardly projecting from the upper surface of the cutting edge body.

A rotatable tool, comprising a tool support body which has an axis and which forms at least one plate seat either directly or in a cartridge in order to receive a cutting plate. By means of a head screw, which passes through the cutting plate, the base of the cutting plate can be pressed against a base support surface, and two plate edges, which form an angle with each other, can be pressed against a respective corresponding edge support surface of the plate seat. Production dimensions are maintained with a low degree of tolerance and the tool is protected from excessive wear to a sufficient degree. Both edge support surfaces are made of support bodies which are movably guided in the tool support body and which can be driven by a corresponding adjustment device in order to finely adjust the cutting plate in a radial and axial direction, respectively.