A two-cutting-edge parting insert including a first cutting portion, a second cutting portion and an elongated body portion connecting the first and second cutting portions. The elongated body portion has a body width (BW) measurable parallel to a lateral axis and a body length (BL) measurable parallel to an elongation axis. The body width is smaller than both cut widths of the cutting edges of the first and second body portions and fulfills the condition: 0.65 mmBW0.95 mm; and the body length fulfills the condition: 2 mmBL14 mm.

An insert may include a first surface, a second surface, a third surface located on a side opposite to the first surface, a cutting edge located on a ridgeline between the first surface and the second surface, and a convex part located more inside the first surface than the cutting edge. The first surface may include a groove extending from a first end part closest to the cutting edge to a second end part. The groove may include an opening located in the first surface, and a bottom surface. An imaginary plane which is orthogonal to a central axis and is located between the first surface and the third surface may be a reference plane, the bottom surface may include an inclined portion inclined so as to come closer to the reference plane as going toward the first end part in a breaker region.

A cutting tool including a substrate and a coating film disposed on the substrate, wherein the cutting tool includes: a rake face, a flank face contiguous to the rake face; and a cutting edge region composed of a boundary part between the rake face and the flank face, wherein the coating film includes a TiSiCN layer, the TiSiCN layer has: a first TiSiCN layer positioned in the rake face; and a second TiSiCN layer positioned in the cutting edge region, the first TiSiCN layer has a composition of Ti.sub.(1-Xr)Si.sub.XrCN, the second TiSiCN layer has a composition of Ti.sub.(1-Xe)Si.sub.XeCN, and the Xr and the Xe each represent 0.010 or more and 0.100 or less, and satisfy a relationship of Xr?Xe?0.003.

Drilling tool systems including a drilling body and a drilling inserts are disclosed. The drilling inserts include four indexable cutting edges. The four cutting edges may each comprise a plurality of cutting edge segments. The plurality of cutting edge segments are provided at distinct angles with respect to a reference plane of the drilling insert to provide effective chip breaking and a stronger cutting edge at the drilling insert corners. Furthermore, the side surfaces of the drilling inserts allow the drilling insert to be more stably supported in a pocket of the drilling body. The drilling inserts may be used in a central pocket of a drilling body.

A method and a device for machining a workpiece rotating about a rotational axis. The machining point moves along the cutting edge of a cutting edge plane and the surface to be machined in a rolling movement on an advancement plane not intersected by the rotational axis. A pivot drive implements a large enough pivot angle so that a first workpiece surface is machined by a machining point moving along the first cutting edge in a first machining step. In a second machining step, a second workpiece surface is machined, wherein the machining point moves along the second cutting edge and the second workpiece surface. The cutting edge has a curvature radius smaller than the distance from the pivot axis of the holder to the cutting edge. The holder can additionally be displaced on the advancement plane with a movement component in a direction transverse to the rotational axis.

A cutting tool according to this invention includes a cutting edge configured to cut a workpiece; a rake surface configured to come in contact with a chip, which appears when the workpiece is cut by the cutting edge; and a relieved surface configured to come in contact with a to-be-cut surface of the workpiece. A plurality of first grooves are formed on a cutting edge side of the rake surface. The plurality of first grooves includes a plurality of aligned grooves arranged adjacent to each other, and a connection groove connecting at least two of the plurality of aligned grooves to each other.

A turning tool (1) that does not easily interfere with other tools and can supply a sufficient amount of coolant is provided. The turning tool (1) includes: a cutting insert (10) which is mirror-image symmetric with respect to a first and second symmetric surfaces (M1, M2); and a tool body (2) which has a first discharge port (5) to supply coolant to a first cutting edge (21E) of the cutting insert (10) from a first rake surface (21R) side. The first discharge port (5) is disposed between a second flat surface (32) and a first reference surface (Vxz) which is parallel with the second flat surface (32) and includes an edge line of the first cutting edge (21E).

A cutting insert includes an upper surface, a lower surface, a side surface, and a cutting edge. The upper surface includes a first side part, a second side part, and a corner part located between the first side part and the second side part. The side surface is located between the upper surface and the lower surface. The cutting edge is located at an intersection of the upper surface and the side surface. The cutting edge includes a first cutting edge located at the corner part, and a second cutting edge adjacent to the first cutting edge and located at the first side part. A height of the first cutting edge relative to the lower surface is constant. The second cutting edge is inclined toward the lower surface as going toward the corner part.

According to the present disclosure, a cutting insert includes an upper surface having a polygonal shape and includes a corner, a side surface adjacent to the upper surface, a cutting edge and a protrusion. The cutting edge is located at a ridge part in which the upper surface intersects with the side surface and includes a corner part located at the corner. The protrusion is located on the upper surface. The protrusion includes a first protrusion on a bisector of the corner in a top view. The protrusion further includes a second protrusion adjacent to the first protrusion in a direction orthogonal to the bisector. The second protrusion is closer to the corner than the first protrusion in the top view.

A cutting insert may include a coupling part, a cutting part, a connection part, a clamping part, and a recess part. Also, the cutting part may include a cutting body part through which the clamping part passes and a cutting edge disposed along an outer circumference of the cutting body part, and the cutting edge may include a main cutting edge provided in plurality to cut the workpiece, a corner cutting edge provided in number corresponding to that of the main cutting edge and extending curvedly from the main cutting edge, a minor cutting edge provided in number corresponding to that of the corner cutting edge and extending from the corner cutting edge to cut the workpiece, and an inclined cutting edge having one end connected to the minor cutting edge and the other end connected to the main cutting edge.