The invention relates to an apparatus for processing cylinder walls of internal combustion engines (1), including a cutting element (4). The cutting element (4) is arranged on a rotary cutting ring (3). The cutting element (4) has a slit contour (5) with a plurality of cutting edges (6) arranged next to each other in a direction of an axis of rotation of the rotary cutting ring. And, the individual cutting edges (6) face in a direction of rotation of the rotary cutting ring.

There is provided a rotary tool including a rotary tool body and a blade provided to the rotary tool body and having a cutting edge, the blade containing 80% by volume or more of diamond, and the blade including a land surface extending along the cutting edge, and a chip breaker having a recess located opposite to the cutting edge with the land surface therebetween.

The technical objective of the present invention is to provide a cutting insert that has an improved fastening property with a cutting tool, thereby preventing reduction of the service life. To this end, the cutting insert according to the present invention has three corners along the circumference thereof; an upper main cutting edge, which is formed on the edge between the upper surface and the first side surface, and an upper sub cutting edge, which is formed on the edge between the upper surface and the second side surface, are continuously disposed between respective corners; the lower surface has the same shape as that of the upper surface; and the angle defined between the upper main cutting edge and the upper sub cutting edge, which are placed on both sides with reference to each corner, is larger than or equal to 85? and is smaller than 90?.

A milling insert, including an upperside, an underside, and a reference plane parallel thereto. A plurality of indexable cutting edges are formed along a peripheral borderline in transitions between at least the upperside and a number of clearance surfaces. Each cutting edge includes a chip-removing main edge and a surface-wiping secondary edge. The main edge, from a first end of the main edge adjacent to the secondary edge, first declines toward the underside of the milling insert and then, from a lowest part, rises toward an opposite second end of the main edge. The secondary edge is inclined at an angle () in relation to the reference plane as viewed perpendicularly to the clearance surface of the secondary edge, such that a first end of the secondary edge connected to the main edge is situated on a lower level than the opposite, second end of the secondary edge.

Provided is a cutting insert capable of suppressing edge fracture when a work having high hardness is machined. A cutting insert includes two end surfaces having a plurality of corner parts and opposed to each other, a peripheral side surface extending between the two end surfaces, and a cutting edge formed at an intersecting edge between at least one of the two end surfaces and the peripheral side surface. The cutting edge has at least a first corner edge, a second corner edge, a major cutting edge, and an end cutting edge. The end cutting edge has a circular-arc shape, which projects outward, as viewed from the side of the end surface. The end cutting edge has a width which is from 15% to 50% of the width of the cutting insert. The end cutting edge has an arc radius which is from to 1/1 of the width of the cutting insert.

An indexable rotary cutting tool comprising, a twist angle of the outer peripheral cutting edge having a positive value, an axial rake angle of the cutting edge of the corner R at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value, the axial rake angle of the cutting edge of the corner R at the reference point has a negative value, at least the radial rake angle in a region between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value, and the radial rake angle of the cutting edge of the corner R at the reference point is smaller than the radial rake angle of the cutting edge of the corner at the boundary point.

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 ?m to ?0.5 ?m. A skewness Rsk at the third breaker part is ?0.2 ?m or less. The skewness Rsk at the constraining surface is smaller than the skewness Rsk at the third breaker part.

There is provided a rotary tool including a rotary tool body and a blade provided to the rotary tool body and having a cutting edge, the blade containing 80% by volume or more of diamond, and the blade including a land surface extending along the cutting edge, and a chip breaker having a recess located opposite to the cutting edge with the land surface therebetween.

A cutting insert has top and bottom surfaces opposing each other and a side surface connecting them. A part of an intersecting ridge between the top and side surfaces functions as a cutting edge. On the side surface, a side surface portion adjacent to the intersecting ridge portion opposing the cutting edge intersects the top surface at an acute angle. At least on a part of a bottom surface, an inclined surface gradually approaching the top surface with increasing distance from a side surface portion on a side opposite to a cutting edge is formed. This allows a part of the cutting resistance to act on the side surface portion. As a result, friction resistance between the side surface portion and the side surface of an insert seat becomes larger, thereby suppressing a shifting of the cutting insert when cutting.

A double-sided, indexable cutting insert for a milling cutter includes a first surface, a second surface, and side surfaces. Cutting edges are defined at an intersection between the first and second surfaces and side surfaces. Each cutting edge includes a first cutting-edge portion, a second cutting-edge portion and a third cutting-edge portion. The first and second surfaces include diagonally opposite recessed regions. The cutting insert is mounted in a milling cutter defining a radial rake angle, A, and a ramping angle, B, with respect to a central, rotational axis of the milling cutter that provide superior performance for both milling and ramping cutting operations.