A cutting tool has an insert holder with an indexable cutting insert removably secured therein. The cutting insert has upper and lower end surfaces with a peripheral side surface and a through bore extending therebetween, and a plurality of upper cutting edges formed on an upper peripheral edge. The peripheral side surface includes a non-circular upper relief surface adjacent the upper peripheral edge and a circular upper abutment surface spaced apart from the upper peripheral edge. Each upper cutting edge exhibits mirror symmetry about a bisector plane, and is non-linear in a side view. The through bore has an inner undercut formed by upper and lower bore surfaces located on opposite sides of a median plane, and a clamping member makes contact with one of the upper and lower bore surfaces at an inner contact zone located between the median plane and a seat surface of the insert holder.

A turning insert includes a top surface, an opposite bottom surface, and a reference plane therebetween. A center axis intersects the top and bottom surfaces and a side surface connects the top and bottom surfaces. A circular cutting edge is adjacent the top surface and the side surface. The top surface includes a set of first protrusions, which are elongated in a direction parallel to the adjacent cutting edge. A greatest distance from the reference plane to the first protrusions is greater than a distance from the reference plane to the cutting edge. The bottom surface has a set of radial grooves and includes a set of flat surfaces. The flat surfaces extend in a plane parallel to the reference plane, wherein in a top view each first protrusion is symmetrical in relation to a line extending between the center axis and a mid-point of the first protrusion.

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 turning tool includes a tool body, insert seat and a turning insert. The turning insert has a top surface and an opposite bottom surface, a reference plane between the top and bottom surfaces, and a center axis intersecting the top and bottom surfaces. A circular cutting edge of the insert is concentric in relation to the center axis. The bottom surface includes a set of radial grooves and a set of flat surfaces. The flat surfaces extend in a plane parallel to the reference plane. The insert seat includes a bottom surface and a rear surface. The bottom surface of the insert seat has a first ridge and a support surface, wherein at least one of the flat surfaces of the turning insert is in contact with the support surface. A cross-section of the first ridge is smaller than a corresponding cross section of one of the radial grooves.

A cutting insert includes a body made of a ceramic material. The body has a first surface, a second surface and at least one flank surface extending between the first surface and the second surface. The first surface includes a chip forming feature extending in a radially outwardly direction to a cutting edge and extending in a radially inwardly direction to an inner edge. The chip forming feature includes a front wall that slopes downward from the cutting edge radially inward toward a rounded bottom surface and a back wall that slopes upward from the rounded bottom surface radially inward to the inner edge. The chip forming feature can include an optional land surface between the cutting edge and the front wall.

Provided is a cutting-edge replaceable cutting tool having a configuration capable of stably supporting a rotational moment acting on a cutting insert clamped on an insert mounting face of a body. It includes a cutting insert, a body including an insert mounting portion for removably mounting the cutting insert and a reception mechanism to receive the rotational moment acting on the cutting insert so as to rotate the cutting insert mounted on the insert mounting portion on a base surface, the mechanism including a first engagement portion formed on a lower surface of the cutting insert and a second engagement portion formed on the base surface of the insert mounting portion which is formed to engage with a specific portion of a surface defining the first engagement portion to receive the rotational moment.

A cutting tool has an indexable cutting insert removably secured to a holding portion of an insert holder. The cutting insert has opposing first and second end surfaces with an insert peripheral surface and a central axis extending therebetween, at least two cutting portions, and at least one mounting cut-out. Each cutting portion has a cutting edge formed by the intersection of rake and relief surfaces formed on the insert peripheral surface, one rake surface facing in a first rotary direction about the central axis and one rake surface facing in an opposite second rotary direction. Each mounting cut-out extends between the first and second end surfaces and has spaced apart first and second flank surfaces disposed on a cut-out peripheral surface which is separate and spaced apart from the insert peripheral surface. The first and second flank surfaces face in the first and second rotary directions, respectively.