A cutting insert according to one non-limiting example has a quadrangular prism shape extending from a front end toward a rear end along a central axis, and comprises a cutting portion, and a main body portion. The main body portion has an upper surface having a V-shaped flute extending along the central axis. An opening portion and a bottom portion of the flute each have a convex shape protruding upward in a direction along the central axis. A first flute has a first region positioned on the rear end side and a second region positioned on the front end side with respect to the first region. An opening angle of the first flute in the first region is smaller than an opening angle of the first flute in the second region.

A cutting insert according to one non-limiting example has a quadrangular prism shape extending from a front end toward a rear end along a central axis, and comprises a cutting portion, and a main body portion. The main body portion includes an upper surface including a first flute having a V-shape extending along the central axis, and a lower surface including a second flute having a V-shape extending along the central axis. A first flute has a first region positioned on the rear end side and a second region positioned on the front end side with respect to the first region. An opening angle of the first flute in the first region is smaller than an opening angle of the first flute in the second region. An opening angle of the second flute is constant in a direction along the central axis.

A cutting insert may include an upper surface, a lower surface, a front lateral surface and a rear lateral surface. The upper surface may include a first upper cutting edge and an upper constraining surface. The lower surface may include a lower constraining surface. The lower constraining surface may include a lower groove. The lower groove may include a first region, a second region and a third region. The first region may be located on a side opposite to the upper constraining surface. A wedge angle of the first region may be a first angle, a wedge angle of the second region may be a second angle, and a wedge angle of the third region may be a third angle. The first angle may be smaller than each of the second angle and the third angle.

A cutting tool system comprising a carrier tool, a cutting plate having a clamping recess and a clamping element with an associated clamping bolt, wherein on the underside of the clamping element, which underside faces the cutting plate, an engagement element is arranged that is in clamping contact with the clamping recess in the engaged state and thereby anchors the cutting plate, and the clamping element is guided via a chamfer in such a manner that when tightening the clamping bolt, the clamping element is pulled in the clamping direction.

A cutting insert may include an upper surface, a lower surface, a front lateral surface and a rear lateral surface. The upper surface may include an upper constraining surface. The lower surface may include a lower groove having a V-shape. The lower groove may include a first region, a second region, a third region a first portion and a second portion. A length of a line segment connecting the first portion and the second portion in the first region may be a first length, a length of a line segment connecting the first portion and the second portion in the second region may be a second length, and a length of a line segment connecting the first portion and the second portion in the third region may be a third length. The first length may be larger than each of the second length and the third length.