A cutting insert includes a rake face, a flank face, a cutting edge formed at a ridge where the rake face and the flank face intersect, a land provided on the rake face along the cutting edge, a breaker groove provided in the rake face inside of the land, and a curved surface formed between a groove surface of the breaker groove and the land. A radius of curvature of the curved surface is 0.5 mm or greater.

An object is to prolong the life of a cubic boron nitride cutting tool used for cutting a heat-resistant alloy. A cubic boron nitride cutting tool includes an edge tip made of a sintered cubic boron nitride compact having a thermal conductivity within the range of 20 to 70 W/m.Math.K and including cubic boron nitride particles having an average particle diameter within the range of 0.5 m to 2 m; and a base metal that holds the edge tip at a corner portion of the base metal, wherein a cutting edge formed on the edge tip of the tool has a positive rake angle.

An insert according to an embodiment includes an upper surface including a corner part, a lower surface, a side surface, and a cutting edge. The cutting edge includes a first cutting edge located at the corner part, a second cutting edge adjacent to the first cutting edge, a third cutting edge adjacent to the second cutting edge, and a fourth cutting edge adjacent to the third cutting edge. Each of the third cutting edge and the fourth cutting edge has a concave curvilinear shape extending downward in a side view. A radius of curvature of the fourth cutting edge is smaller than a radius of curvature of the third cutting edge.

A turning tool has a cutting element for a lathe that uses metal-cutting technology, wherein the cutting element has a tool blade, wherein the tool blade of the cutting element has a curvature, in a top view, in which the tool blade intersects a tool axis of the cutting element at a perpendicular angle, in which the cutting element has an opening angle with reference to a center point, wherein the cutting element has asymmetry, in such a manner that the tool axis intersects the opening angle outside the center, and in which, in a top view of the cutting element, the curvature of the tool blade has a constant change in radius.

A cutting insert of one aspect includes a top surface including a corner portion and a pair of side portions each adjacent to the corner portion, a bottom surface, a side surface located between the top surface and the bottom surface, and a corner cutting edge disposed at the corner portion. In such a cutting insert, the top surface includes a first rake surface located along the corner cutting edge, a raised portion located farther on the inner side than the first rake surface, and a second rake surface located between the corner cutting edge and the raised portion. Moreover, a rake angle at a first region of the second rake surface corresponding to a center of the corner cutting edge is greater than a rake angle at a second region of the second rake surface located beside the first region.

An object of the present invention is to configure a cutting-off processing tool that includes a cutting edge angled at an end cutting edge angle and causes evacuation of chips to be controlled so that the chips are evacuated in the tool axis direction, thereby reducing concerns about damage to a processed surface by the chips. The cutting-off processing tool includes a cutting edge angled at the end cutting edge angle. In the cutting-off processing tool, an upper surface has a shape laterally asymmetric about a center in a width direction. In the cutting-off processing tool, when b is a rake angle of a rake face on a first corner side positioned on a foremost end of the tool, and c is a rake angle of the rake face on a second corner side, b>c is satisfied.

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 two-way indexable V-shaped cutting insert having first and second rake surfaces located in a front insert surface thereof. First and second relief surfaces respectively connect the first and second rake surfaces to first and second converging insert abutment surfaces, respectively. A first cutting edge is located at an intersection of the first rake surface and the first relief surface. A second cutting edge is located at an intersection of the second rake surface and the second relief surface. A first relief angle is formed between the first relief surface and the first converging insert abutment surface. A second relief angle is formed between the second relief surface and the second converging insert abutment surface. The first and second relief angles are obtuse. In a cutting tool, the two-way indexable V-shaped cutting insert is releasably secured in a tool holder by means of a fastening member.

cBN sintered material, including cBN particles; a binder phase; and a first phase, wherein the content of the cBN particles in the cBN sintered material is 25% to 80% by volume, the binder phase contains either or both of one or more first compounds, and a solid solution derived from the first compound, the first phase contains cobalt, tungsten, and at least one first element selected from the group consisting of the elements contained in the binder phase, the total content of cobalt and tungsten in the cBN sintered material is 1.0% to 6.0% by mass, the binder phase consists of multiple binder phase particles containing 50% or more of first binder phase particles on a number basis, surfaces of the first binder phase particles include 50% by area or more of a first region which is in contact with the first phase.

A cutting insert includes a rake face, a flank face, and a cutting edge constituted of a ridgeline between the rake face and the flank face. The cutting edge has a first cutting edge portion for corner processing, a second cutting edge portion for low cut-in pulling processing, a third cutting edge portion for high cut-in pulling processing, a fourth cutting edge portion for finished-surface processing, a first connection cutting edge portion, a second connection cutting edge portion, and a third connection cutting edge portion. The fourth cutting edge portion is disposed between the first cutting edge portion and the second cutting edge portion. The second cutting edge portion is disposed between the fourth cutting edge portion and the third cutting edge portion. Each of the first cutting edge portion, the second cutting edge portion, and the fourth cutting edge portion has a curved shape.