A non-indexable, one-sided cutting insert includes opposite insert side surfaces which define an insert width therebetween, opposite insert front and rear surfaces which extend between the insert side surfaces and define an insert depth therebetween and opposite insert top and bottom surfaces which extend between the insert side surfaces and the insert front and rear surfaces. The insert top and bottom surfaces define an insert height therebetween. The insert further includes a main cutting edge formed at an intersection between the insert top and front surfaces. A maximum value of the insert width is smaller than minimum value of the insert height, and a minimum value of the insert depth. The insert includes a deep opening which opens out only to the insert bottom surface and defines an opening depth. A depth ratio defined between the opening depth and the insert height is greater than 0.3.

A cutting insert includes a base body and a coating layer, and also includes a rake surface, a flank surface, and a cutting edge located along an intersecting ridge therebetween. The rake surface includes an outer peripheral part and a middle part protruded relative to the outer peripheral part. The middle part includes a constraining surface. The outer peripheral part includes a first breaker part, a second breaker part, and the third breaker part adjacent to the constraining surface. The constraining surface is configured by the base body and the coating layer does not exist at the constraining surface. A skewness Rsk of a roughness curve at the constraining surface is −1.5 μm to −0.5 μm. A skewness Rsk at the third breaker part is −0.2 μm or less. The skewness Rsk at the constraining surface is smaller than the skewness Rsk at the third breaker part.

A cutting insert suitable for a small-diameter milling tool is provided. A cutting insert has a rake face, a bottom surface, a circumferential side surface, and a through hole. A first ridgeline at which the rake face and the circumferential side surface intersect each other includes a first main cutting edge, and a first corner cutting edge connected to a tip of the first main cutting edge. The bottom surface includes a first bottom surface that comes closer to the rake face gradually toward a side at which the first main cutting edge is located when viewed from a central axis of the through hole, and a second bottom surface that comes closer to the rake face gradually toward a side opposite to the first main cutting edge when viewed from the central axis. A distance between a virtual intersection line, at which a first virtual surface formed by extending the first bottom surface and a second virtual surface formed by extending the second bottom surface intersect each other, and the first main cutting edge decreases from a tip side, at which the tip of the first main cutting edge is located, toward an end side, at which an end opposite to the tip is located, in an extending direction of the first main cutting edge.

A cutting tool has a cutting body with a first insert pocket and an indexable cutting insert removably mounted therein. The first insert pocket has a first seat surface with a plurality of first engagement elements and a first support wall transverse thereto. The cutting insert has upper and lower surfaces and a boundary surface extending therebetween. The lower surface has a plurality of lower engaging elements and the boundary surface has a plurality of alternating first and second peripheral surfaces intersecting the upper surface to form first and second upper cutting edges. In each index position with the lower surface in contact with the first seat surface, the first support wall prevents translation of the cutting insert in a first direction, and the first engagement elements eccentrically contact the lower engaging elements to prevent translation of the cutting insert in a second direction perpendicular to the first direction.

A cutting tool has a cutting body with a first insert pocket and an indexable cutting insert removably mounted therein. The first insert pocket has a first seat surface with a plurality of first engagement elements and a first support wall transverse thereto. The cutting insert has upper and lower surfaces and a boundary surface extending therebetween. The lower surface has a plurality of lower engaging elements and the boundary surface has a plurality of alternating first and second peripheral surfaces intersecting the upper surface to form first and second upper cutting edges. In each index position with the lower surface in contact with the first seat surface, the first support wall prevents translation of the cutting insert in a first direction, and the first engagement elements eccentrically contact the lower engaging elements to prevent translation of the cutting insert in a second direction perpendicular to the first direction.

A cutting insert includes a base body and a coating layer, and also includes a rake surface, a flank surface, and a cutting edge located along an intersecting ridge therebetween. The rake surface includes an outer peripheral part and a middle part protruded relative to the outer peripheral part. The middle part includes a constraining surface. The outer peripheral part includes a first breaker part, a second breaker part, and the third breaker part adjacent to the constraining surface. The constraining surface is configured by the base body and the coating layer does not exist at the constraining surface. A skewness Rsk of a roughness curve at the constraining surface is ?1.5 ?m to ?0.5 ?m. A skewness Rsk at the third breaker part is ?0.2 ?m or less. The skewness Rsk at the constraining surface is smaller than the skewness Rsk at the third breaker part.

A non-indexable, one-sided cutting insert includes opposite insert side surfaces which define an insert width therebetween, opposite insert front and rear surfaces which extend between the insert side surfaces and define an insert depth therebetween and opposite insert top and bottom surfaces which extend between the insert side surfaces and the insert front and rear surfaces. The insert top and bottom surfaces define an insert height therebetween. The insert further includes a main cutting edge formed at an intersection between the insert top and front surfaces. A maximum value of the insert width is smaller than minimum value of the insert height, and a minimum value of the insert depth. The insert includes a deep opening which opens out only to the insert bottom surface and defines an opening depth. A depth ratio defined between the opening depth and the insert height is greater than 0.3.

A rotary cutting tool includes a cutter body having a plurality of insert-receiving pockets. Each pocket includes a bottom support surface, an axial support surface, a radial support surface, a top clearance surface and an intermediate clearance surface extending between the axial support surface and the top clearance surface. A cutting insert includes a helical top surface, a helical side surface, a side surface opposite the helical side surface, a pair of opposed side walls, a bottom surface, and a cutting edge formed at an intersection between the helical top surface and the helical side surface. The cutting insert further includes an undercut for accommodating the axial support surface, the top clearance surface and the intermediate clearance surface of the pocket when the cutting insert is mounted in the pocket.

A rotary cutting tool includes a cutter body having a plurality of insert-receiving pockets. Each pocket includes a bottom support surface, an axial support surface, a radial support surface, a top clearance surface and an intermediate clearance surface extending between the axial support surface and the top clearance surface. A cutting insert includes a helical top surface, a helical side surface, a side surface opposite the helical side surface, a pair of opposed side walls, a bottom surface, and a cutting edge formed at an intersection between the helical top surface and the helical side surface. The cutting insert further includes an undercut for accommodating the axial support surface, the top clearance surface and the intermediate clearance surface of the pocket when the cutting insert is mounted in the pocket.