Embodiments of a cutting insert are provided. The cutting insert includes an upper surface, a lower surface, a plurality of side surfaces extending between the upper surface and the lower surface, an insert hole extending through the upper surface and the lower surface, and a corner portion provided with a cutting edge. At least one of the upper surface and the lower surface has a plurality of recesses extending between the insert hole and the corner portion. The plurality of recesses includes a first recess into which one portion of the mounting portion is inserted when the cutting insert is supported by the mounting portion, and a second recess into which another portion of the mounting portion is inserted when the cutting insert is supported by the mounting portion. The second recess has a side wall spaced apart from another portion of the mounting portion.

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.

Embodiments of a cutting insert are provided. The cutting insert includes an upper surface, a lower surface, a plurality of side surfaces extending between the upper surface and the lower surface, an insert hole extending through the upper surface and the lower surface, and a corner portion provided with a cutting edge. At least one of the upper surface and the lower surface has a plurality of recesses extending between the insert hole and the corner portion. The plurality of recesses includes a first recess into which one portion of the mounting portion is inserted when the cutting insert is supported by the mounting portion, and a second recess into which another portion of the mounting portion is inserted when the cutting insert is supported by the mounting portion. The second recess has a side wall spaced apart from another portion of the mounting portion.

In an insert clamping mechanism of an indexable grooving tool of the present invention, a shaft portion of a clamping tool has a major axis and a minor axis orthogonal to each other on a center axis thereof in a cross-sectional view perpendicular to the center axis. At least one end portion of the both end portions positioned on the major axis in an outer circumference of the shaft portion is formed into a recessed shape or a linear shape and is disposed not to come into contact with an upper wall and a lower wall of an opening-closing operation slit. Support portions are respectively formed in parts adjacent to the end portions on both sides around the center axis along the shaft portion.

In an insert clamping mechanism of an indexable grooving tool of the present invention, a shaft portion of a clamping tool has a major axis and a minor axis orthogonal to each other on a center axis thereof in a cross-sectional view perpendicular to the center axis. At least one end portion of the both end portions positioned on the major axis in an outer circumference of the shaft portion is formed into a recessed shape or a linear shape and is disposed not to come into contact with an upper wall and a lower wall of an opening-closing operation slit. Support portions are respectively formed in parts adjacent to the end portions on both sides around the center axis along the shaft portion.

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.