An indexable parting blade has opposite blade first and second sides, a blade peripheral edge, a central index axis, and at least first, second and third insert pockets located along the blade peripheral edge. The parting blade also has first, second and third coolant channels, each forming a coolant path from a corresponding inlet to a corresponding one of the insert pockets. Each coolant channel includes a rake outlet opening out to a rake side of its corresponding insert pocket and a relief outlet opening out to a relief side of that same insert pocket. The inlet corresponding to a given coolant channel is located further from that coolant channel's insert pocket than at least one of (a) the inlet corresponding to a different coolant channel, and (b) the central index axis.

A holder according to one embodiment has a rod shape and includes a head portion located at a front end side. The head portion includes an upper jaw portion and a lower jaw portion located at a front end, an insert pocket located between the upper jaw portion and the lower jaw portion, a first wall surface located at an upper surface of the upper jaw portion and inclined in an extending manner from one side surface side, a second wall surface located closer to a rear end side than the first wall surface and inclined upward, a concave-shaped third wall surface located closer to the rear end side than the second wall surface, and a fourth wall surface inclined upward as the fourth wall surface extends away from the third wall surface. The third wall surface is concave downward from an upper end of the second wall surface.

A holder according to one embodiment has a rod shape and includes a head portion located at a front end side. The head portion includes an upper jaw portion and a lower jaw portion located at a front end, an insert pocket located between the upper jaw portion and the lower jaw portion, a first wall surface located at an upper surface of the upper jaw portion and inclined in an extending manner from one side surface side, a second wall surface located closer to a rear end side than the first wall surface and inclined upward, a concave-shaped third wall surface located closer to the rear end side than the second wall surface, and a fourth wall surface inclined upward as the fourth wall surface extends away from the third wall surface. The third wall surface is concave downward from an upper end of the second wall surface.

An insert may include a main body. The main body may include a first surface, a second surface, a side surface, a first cutting edge and a through hole. The side surface may be located between the first surface and the second surface. The first cutting edge may be located on at least a part of a ridge line where a first side surface of the side surface intersects with a second side surface adjacent to the first side surface. The through hole may open into the first surface. The main body may further include a first concave part located from the first surface to the side surface. The first concave part may be located away from an imaginary straight line connecting the first cutting edge and a center of the through hole in a front view of the first surface.

An insert may include a main body. The main body may include a first surface, a second surface, a side surface, a first cutting edge and a through hole. The side surface may be located between the first surface and the second surface. The first cutting edge may be located on at least a part of a ridge line where a first side surface of the side surface intersects with a second side surface adjacent to the first side surface. The through hole may open into the first surface. The main body may further include a first concave part located from the first surface to the side surface. The first concave part may be located away from an imaginary straight line connecting the first cutting edge and a center of the through hole in a front view of the first surface.

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.

Tool system 1 comprising a tool holder 2 that has an insert seat 17 for receiving a cutting insert 6, and comprising a clamping element 4 that has an opening 26 for receiving a clamping means 15, an interface 30 being arranged between the tool holder 2 and the clamping element 4, and channels for the purpose of cooling by means of a fluid being arranged in the tool holder 2 and the clamping element 4, and a sealing means 31 being arranged in the region of the interface 30.

Tool system 1 comprising a tool holder 2 that has an insert seat 17 for receiving a cutting insert 6, and comprising a clamping element 4 that has an opening 26 for receiving a clamping means 15, an interface 30 being arranged between the tool holder 2 and the clamping element 4, and channels for the purpose of cooling by means of a fluid being arranged in the tool holder 2 and the clamping element 4, and a sealing means 31 being arranged in the region of the interface 30.

A blade positioning structure of a disposable milling cutter includes a cutter body and a disposable blade. The cutter body is peripherally provided with a blade seat. By passing a screw through the disposable blade and the blade seat, the disposable blade is locked to the blade seat. The blade seat has a blade seat surface and a sidewall; the blade seat surface has a groove; the disposable blade has a bottom surface provided with a projection corresponding in shape to the groove; and when the disposable blade is locked to the blade seat, the blade seat surface and the groove of the latter lie respectively and tightly against the bottom surface and the projection of the former.

A blade positioning structure of a disposable milling cutter includes a cutter body and a disposable blade. The cutter body is peripherally provided with a blade seat. By passing a screw through the disposable blade and the blade seat, the disposable blade is locked to the blade seat. The blade seat has a blade seat surface and a sidewall; the blade seat surface has a groove; the disposable blade has a bottom surface provided with a projection corresponding in shape to the groove; and when the disposable blade is locked to the blade seat, the blade seat surface and the groove of the latter lie respectively and tightly against the bottom surface and the projection of the former.