An insert includes a base. The base includes first and second surfaces, and a cutting edge on at least a part of a ridgeline of the first and second surfaces. The first surface includes a groove away from the ridgeline and at an angle ?1 of 20-90? relative to the ridgeline. The groove extends from a first end part closest to the cutting edge to a second end part most away from the cutting edge. The groove includes an opening and a bottom surface. An angle ?2 formed by the bottom surface and a raised surface extended from the bottom surface toward the first end part is 95-135?. A cutting tool includes a holder, which has a length extending from a first end to a second end and includes a pocket located on a side of the first end, and the insert located in the pocket.

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 in the cutting edge side of the rake surface. A plurality of second grooves are formed in the cutting edge side of the relieved surface.

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 first region, a second region and a third region. The first region may be located on a side opposite to the upper constraining surface. The second region may be located closer to the front lateral surface than the first region. The third region may be located closer to the rear lateral surface than the first region. 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 coated tool includes a base body and a coating layer with crystals having a cubic structure. The coating layer has a striped structure with two layers alternating in a thickness direction. The two layers contain Si and at least one metal element, and differ from each other in a content of the metal element. The two layers each contain crystals having a cubic structure. A peak angle of a (200) plane of a crystal having a cubic structure by X-ray diffraction of the coating layer is a first angle, a peak angle of a (200) plane of a crystal having a cubic structure by X-ray diffraction of the coating layer after heat treatment of the coated tool in a nitrogen atmosphere at 900? C. for 1 hour is a second angle, and a difference between the first angle and the second angle is 0.05? or less.

A cutting insert, a holder, and a cutting tool with which the cutting insert can be easily and stably mounted on the holder and a fabrication target object can be excellently fabricated are provided. A cutting tool 100 that is used to fabricate a fabrication target object W by cutting includes a holder 50 and a cutting insert 10 that is mounted on a distal end of the holder 50. The holder 50 includes an insert pocket 53 into which the cutting insert 10 is fitted and a stopper portion 61 that elastically locks the cutting insert 10 to be fitted into the insert pocket 53. The cutting insert 10 includes a cutting portion 11 including a cutting edge 13, a fitting portion 12 that is fitted into the insert pocket 53, and a lock portion 21 that is formed at the fitting portion 12 and is to be locked to the stopper portion 61 of the holder 50.

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 cutting tool for cutting a rotationally symmetrical surface of a rotating workpiece includes the step of feeding the cutting tool in a direction inclined with respect to a rotational axis of the rotationally symmetrical surface, while holding the cutting tool in contact with the rotationally symmetrical surface. In the step of feeding the cutting tool, the cutting tool has a point that is in contact with the rotationally symmetrical surface and the point shifts as the cutting tool is fed. The cutting tool includes: a rake face; a flank face; and a cutting edge connecting the rake face and the flank face. The cutting edge as seen from above the flank face has a shape including at least one arc, and the arc has a radius of curvature of not less than 100 mm and not more than 500 mm.

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.

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 (100,100) includes a body (102) having a top face (104), a bottom face (106) opposite the top face (104), and at least one flank face (108, 110, 112, 114). A coolant inlet aperture (126), a coolant outlet aperture (132, 134), and an internal coolant passage (128, 130) in fluid communication with the coolant inlet aperture (126) and the coolant outlet aperture (132, 134) are formed using electro-magnetic radiation. The coolant inlet aperture (126) can be formed in the top face (104), the bottom face (106) and/or the flank face (108, 110, 112, 114), and the coolant outlet aperture (132, 134) can be formed in any different face (104, 106, 108, 110, 112, 114). A method of forming the internal coolant passages (128, 130) is described.