A cutting tool includes a substrate and a diamond layer that covers the substrate. The diamond layer includes a rake face and a flank continuous to the rake face. A ridgeline between the rake face and the flank forms a cutting edge. The substrate includes a top surface opposed to the rake face. When viewed in a direction perpendicular to the top surface, the rake face includes a plurality of protrusions. In a cross-section perpendicular to a direction of extension of the cutting edge, each of the plurality of protrusions includes an inclined portion and a curvature portion continuous to the inclined portion. In the cross-section, a height of the inclined portion in the direction perpendicular to the top surface increases as a distance from the cutting edge increases.

A single-crystal diamond cutting tool is provided with a flank and a rake face, a cutting edge being provided at a boundary between the flank and the rake face, an inclined surface being provided at a location distant from the cutting edge, the inclined surface being contiguous to the rake face and inclined at 0.05 degrees or more and 80 degrees or less with respect to the rake face, the rake face having a roughness Ra of 1 .Math.m or less, the cutting edge being provided with a chamfered surface or round honing having a width of 1 .Math.m or less, the cutting edge having projections and depressions having a width of 100 nm or less and smaller than that of the chamfered surface or round honing.

A parting/grooving insert and a method of grinding a parting/grooving insert including rotating a plane grinding surface having a normal vector parallel to the axis of rotation and a tangential direction of rotation; providing a parting/grooving insert including a rake surface, a main clearance surface, and a main cutting edge formed between the rake and main clearance surfaces; orienting/positioning the insert relative to the grinding surface, such that the main clearance surface is parallel to the grinding surface, the normal vector of the main cutting edge being in the plane of the main clearance surface and with a vector component in the direction of rotation forming an angle to the tangential direction of rotation at the insert of at least 20 degrees from parallel orientation; and grinding the main clearance surface to provide grinding marks having an angle to the normal vector of the main cutting edge corresponding to the angle to the tangential direction of rotation.

A cutting insert includes a body having an upper face, a lower face, a plurality of planar flank faces joining the upper and lower faces, and a plurality of curved flank faces joining the plurality of flank faces. A T-land is formed at a downward sloping angle with respect to the upper face. A cutting edge is formed at an intersection of a respective flank face and the T-land. A curved cutting edge is formed at an intersection of a respective curved flank face and the T-land. A micro-channel is formed in one of the flank faces, the curved flank faces and the T-land and proximate one of the cutting edge and the curved cutting edge.

The present invention provides a cutting tool that can firmly hold four types of cutting inserts by one tool main unit. A cutting insert of a cutting tool 1 has an approximately triangular stereoscopic shape including three corner portions. A tool main unit has a fixing portion that can selectively fix a plurality of types of cutting inserts, including: a negative type cutting insert of which angle of the corner portion exceeds 60°, a positive type cutting insert of which angle of the corner portion exceeds 60°; a negative type cutting insert of which angle of the corner portion is less than 60°; and a positive type cutting insert of which angle of the corner portion is less than 60°. The fixing portion has a bottom face that contacts with a bottom face of the cutting insert, and a side wall face that contacts with a side face of the cutting insert. A portion, which contacts with the cutting insert, of the side wall face of the fixing portion differs depending on the type of the cutting insert.

A turning tool for internal turning of a metal work piece having a rear end, an opposite forward end and a longitudinal center axis extending therebetween. The first nose cutting edge includes a first radially distal point having an associated first rake face and separates and connects a first forward cutting edge and a first rearward cutting edge. A second nose cutting edge of the turning tool includes a second radially distal point having an associated second rake face and separates and connects a second forward cutting edge and a second rearward cutting edge. The second radially distal point is positioned ahead of the first radially distal point. The first forward cutting edge forms an acute first entering angle, the second forward cutting edge forms an obtuse second back clearance angle, and the second rearward cutting edge forms an acute second entering angle.

A cutting part (1) for a tool head (2) for a lathe (3) for machining a workpiece (4), having a cutting edge (5) for removing material from the workpiece (4) and having a rake face (6) for guiding away the removed material or cuttings. The problem of providing a cutting part (1) which can be realized in a simple manner and with which lead-free materials can also be machined is solved in that a flat structure (7) is formed in the rake face (6) of the cutting part (1) adjoining the cutting edge (5) for breaking the cuttings. A lathe (3) for machining a workpiece (4), having a tool head (2) is provided with at least one such cutting part (1).

The present invention provides a cutting tool that can firmly hold four types of cutting inserts by one tool main unit. A cutting insert of a cutting tool 1 has an approximately triangular stereoscopic shape including three corner portions. A tool main unit has a fixing portion that can selectively fix a plurality of types of cutting inserts, including: a negative type cutting insert of which angle of the corner portion exceeds 60°, a positive type cutting insert of which angle of the corner portion exceeds 60°; a negative type cutting insert of which angle of the corner portion is less than 60°; and a positive type cutting insert of which angle of the corner portion is less than 60°. The fixing portion has a bottom face that contacts with a bottom face of the cutting insert, and a side wall face that contacts with a side face of the cutting insert. A portion, which contacts with the cutting insert, of the side wall face of the fixing portion differs depending on the type of the cutting insert.

In accordance with various illustrative embodiments of the present disclosure, a rotationally symmetric surface of a workpiece is machined by a turning apparatus, wherein the workpiece is rotationally driven around a rotational axis, a cutting tool with a cutting edge positioned at the edge of a rake face is arranged relative to the workpiece, the cutting tool is brought into contact with the workpiece, and the cutting tool is advanced relative to the workpiece along a feed direction parallel to the rotational axis, the normal to the rake face being tilted relative to the feed direction, a first axis and a second axis, the first axis and the second axis are perpendicular to the feed direction and perpendicular to each other.

A parting/grooving insert and a method of grinding a parting/grooving insert including rotating a plane grinding surface having a normal vector parallel to the axis of rotation and a tangential direction of rotation; providing a parting/grooving insert including a rake surface, a main clearance surface, and a main cutting edge formed between the rake and main clearance surfaces; orienting/positioning the insert relative to the grinding surface, such that the main clearance surface is parallel to the grinding surface, the normal vector of the main cutting edge being in the plane of the main clearance surface and with a vector component in the direction of rotation forming an angle to the tangential direction of rotation at the insert of at least 20 degrees from parallel orientation; and grinding the main clearance surface to provide grinding marks having an angle to the normal vector of the main cutting edge corresponding to the angle to the tangential direction of rotation.