An insert based on an aspect includes a first face, a second face located opposite to the first face, a third face located between the first face and the second face, and a cutting edge located on an intersection of the first face and the third face. The first face includes a first region inclined so as be close to the second face as being separated away from the cutting edge. A virtual straight line orthogonal to the cutting edge is set as a first virtual straight line in a front view of the first face. A ten-point average of roughness the first region in a direction along the first virtual straight line is expressed by Rz1a and a ten-point average of roughness of the first region in a direction along the cutting edge is expressed by Rz1b, and Rz1a is larger than Rz1b.

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 physical configuration of multiple-layer coatings formed with at least one layer of coating containing cubic born nitride (cBN) particles with one or more layers in composite form containing cBN particles may have a thickness of each individual layer as thin as in the nanometer range, or as thick as in the range of a few microns and even up to tens of microns. The chemistry of the composite layer consists of any individual phase of (a) nitrides such as titanium nitride (TiN), titanium carbonitride (TiCN), and hafnium nitride (HfN); (b) carbides such as titanium carbide (TiC); and (c) oxides such as aluminum oxide (AI.sub.2O.sub.3) or any combination of the above phases, in addition to cBN particles. The coating or film can be stand-alone or on a substrate.

A cutting insert in the present disclosure includes an upper surface, a lower surface, a side surface, and an edge. The upper surface includes a first corner part and a second corner part. The edge is located in a region which is located between the first corner part and the second corner part. The edge includes a first edge located at a side of the first corner part, a second edge located at a side of the second corner part, and a third edge located between the first edge and the second edge. The edge has a curvilinear shape being recessed toward the lower surface in a side view. Each of a radius of curvature R1 of the first edge and a radius of curvature R2 of the second edge is smaller than a radius of curvature R3 of the third edge in a side view.

A rotary cutting tool insert according to one embodiment of the present invention includes: an annular rake face provided with at least one recess portion; and a cutting edge formed at an outer circumference of the rake face, the recess portion having a width of more than or equal to 1.2 mm and less than or equal to 3.0 mm in a circumferential direction of the rake face, a distance between the cutting edge and an end of the recess portion at the outer circumference side of the rake face being more than or equal to 0.1 mm and less than or equal to 0.5 mm. According to the rotary cutting tool insert according to the one embodiment of the present invention, roughness of a processed surface and vibration due to a cutting process can be prevented.

A cutting tool according to an aspect of the present disclosure includes a cutting edge portion which contains at least one of cubic boron nitride and polycrystalline diamond. The cutting edge portion includes a flank face, a negative land contiguous to the flank face, and a cutting edge formed by a ridgeline between the flank face and the negative land. At least one of the negative land and the flank face is provided with a plurality of recesses and a projection. The projection is formed by arranging the edges of adjacent recesses in contact with each other.

The invention relates to a drilling tool (50), in particular a dowel hole drill, for the machining of workpieces, in particular workpieces made of wood, plastics, composite materials, comprising a drill shaft (56) with a front surface (60), and to a drill head (58) with at least one cutting edge (66), which is firmly connected, such as soldered, to the drill shaft (56). In order to make available a drilling tool of the type mentioned at the start, which has a broad range of application and is simple to produce, it is provided that the drill head (58) is formed from a composite material with exclusively two layers (38), namely a hard metal layer (36) and an ultra-hard layer (38) which is connected to the hard metal layer (36) and preferably formed from polycrystalline diamond or polycrystalline boron nitride, that the ultra-hard layer (38) is connected directly to the front surface (60) of the drill shaft (56) and that the at least one cutting edge (66) is formed by the ultra-hard layer (38), and a drill bit (62) such as a centering tip is formed by the hard metal layer (36).

A cutting insert according to an aspect includes a base portion and a cutting portion. The cutting portion includes an upper surface, a side surface, a ridge line including a first ridge line and a second ridge line, and an intersection point. The upper surface includes a top surface region and a rising surface region located between the top surface and the ridge line, and having a shape protruding toward the intersection point. In a top view, a first distance from the first ridge line to the rising surface increases as close to the intersection point, and a second distance from the second ridge line to the rising surface increases as close to the intersection point.

A cutting insert is described. It has a cutting insert body with a central mounting section and at least one cutting edge. The cutting edge is wave-shaped and generally descending from an end section of the cutting edge towards a middle section of the cutting edge. Furthermore, a chip guiding recess extends substantially along the at least one cutting edge and is arranged between the cutting edge and the central mounting section. A chip breaker element is arranged in the chip guiding recess. The chip breaker element comprises a first portion having a first width and a second portion having a second width, wherein a transition between the first portion and the second portion is formed as a step.

An insert includes an upper surface including at least one corner part and a plurality of side parts, and a side surface. The upper surface includes a corner region. The corner region includes a first corner surface, a second corner surface, a third corner surface, and a fourth corner surface which are located sequentially in order from a side of the corner part. The first corner surface is inclined downward. The second corner surface, the third corner surface and the fourth corner surface are inclined upward. An inclination angle 12 of the second corner surface is greater than an inclination angle 13 of the third corner surface. An inclination angle 14 of the fourth corner surface is greater than the inclination angle 12 of the second corner surface.