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 rake face, a flank face, and a cutting edge. The flank face is contiguous to the rake face. The cutting edge is provided as a ridge line between the rake face and the flank face. The radius of curvature of the cutting edge is 2 m or more and 8 m or less.

A cutting insert according to an embodiment of the present invention is a double-sided cutting insert comprising an upper surface, a lower surface, a side surface, a cutting edge, and a mounting hole penetrating the upper surface and the lower surface, in which the upper surface is provided with a single upper surface boss portion that surrounds the mounting hole and is flat, the cutting edge includes a main cutting edge, a corner cutting edge extending from the main cutting edge, a sub-cutting edge extending from the corner cutting edge, and a side portion extending from the sub-cutting edge, a first main cutting edge flank surface extending from the main cutting edge forms an acute angle with an extension line of the upper surface boss portion, a sub-cutting edge chip breaker surface extending from the sub-cutting edge is at a gradually increasing angle with the extension line of the upper surface boss portion, as the sub-cutting edge chip breaker surface is distanced away from the corner cutting edge, and when the cutting insert is viewed into the upper surface, a side portion surface extending from the side portion is concavely recessed.

A cutting insert according to an embodiment of the present invention is a double-sided cutting insert comprising an upper surface, a lower surface, a side surface, a cutting edge, and a mounting hole penetrating the upper surface and the lower surface, in which the upper surface is provided with a single upper surface boss portion that surrounds the mounting hole and is flat, the cutting edge includes a main cutting edge, a corner cutting edge extending from the main cutting edge, a sub-cutting edge extending from the corner cutting edge, and a side portion extending from the sub-cutting edge, a first main cutting edge flank surface extending from the main cutting edge forms an acute angle with an extension line of the upper surface boss portion, a sub-cutting edge chip breaker surface extending from the sub-cutting edge is at a gradually increasing angle with the extension line of the upper surface boss portion, as the sub-cutting edge chip breaker surface is distanced away from the corner cutting edge, and when the cutting insert is viewed into the upper surface, a side portion surface extending from the side portion is concavely recessed.

A tool for assisting the process of marking or cutting structures in a predefined manner is disclosed. The tool comprises a rod member having a longitudinal axis and a plate member rotatably attached to the rod member. The tool comprises an arm removably attached to the rod member and to the plate member. The plate member is rotatably attached to the rod member by means of a structure comprising a joint and one or more magnetic or magnetizable structures configured to provide a magnetic force between the rod member and the plate member.

A tool for assisting the process of marking or cutting structures in a predefined manner is disclosed. The tool comprises a rod member having a longitudinal axis and a plate member rotatably attached to the rod member. The tool comprises an arm removably attached to the rod member and to the plate member. The plate member is rotatably attached to the rod member by means of a structure comprising a joint and one or more magnetic or magnetizable structures configured to provide a magnetic force between the rod member and the plate member.

A cutting tool according to one aspect of the present disclosure includes a substrate and a diamond layer coating the substrate. A cutting tool according to one aspect of the present disclosure includes a rake face, a flank contiguous to the rake face, and a cutting edge configured by a ridge formed by the rake face and the flank. The rake face has a first rake face and a second rake face located between the first rake face and the flank. The second rake face and a surface of the substrate located on the side of the rake face form a negative angle. The second rake face is formed at the diamond layer.

A cutting tool according to one aspect of the present disclosure includes a substrate and a diamond layer coating the substrate. A cutting tool according to one aspect of the present disclosure includes a rake face, a flank contiguous to the rake face, and a cutting edge configured by a ridge formed by the rake face and the flank. The rake face has a first rake face and a second rake face located between the first rake face and the flank. The second rake face and a surface of the substrate located on the side of the rake face form a negative angle. The second rake face is formed at the diamond layer.

A cutting insert has a seating surface, an outer peripheral surface, a top surface, and an attachment hole. The cutting edge includes a curved cutting corner edge portion, a first cutting edge portion, and a second cutting edge portion. The top surface includes a first rake face contiguous to the first cutting edge portion, a second rake face contiguous to the second cutting edge portion, and a third rake face contiguous to the cutting corner edge portion and also contiguous to the first and second rake faces. The third rake face has a first region contiguous to the first rake face and a second region contiguous to the second rake face. The first rake face and the first region each have a rake angle which is a positive angle. The second rake face and the second region each have a rake angle which is a negative angle.

This cutting insert has: as cutting edges, arcuate cutting edges that are of an arc shape protruding toward an outer circumference side of a distal end. A chisel part is formed at an intersecting ridge line part between the flank faces of the pair of arcuate cutting edges. A round honing is formed on the cutting edge tip of the arcuate cutting edge at least in a range where a radial angle is 30 or less. A curvature radius of the round honing in a cross section perpendicular to the edge length direction of the arcuate cutting edge is 20 to 40 m. A chisel angle formed between the distal end part of the arcuate cutting edge and a chisel edge of the chisel part is 150 to 170 as seen in an insert front view.

A modular rotary cutting tool includes a cutting head for insertion into a support. The cutting head has a coupling pin having torque surfaces and clamping surfaces formed on its outer peripheral surface. The coupling pin is divided into a front pin part and a rear pin part. The front pin part is defined by a circumferential groove. Stop surfaces for an axial pullout prevention are formed between the front pin part and the rear pin part. The torque surfaces and the clamping surfaces are arranged in different pin parts. For example, the clamping surfaces are preferably formed on the front pin part and the torque surfaces are preferably formed on the rear pin part. The clamping surfaces taper radially inward in a direction of the front cutting part at an angle of inclination, 2, with respect to the axis of rotation. Other variants and embodiments are broadly contemplated herein.