Abstract: A boring tool has a cutting insert, a holder, and a pressing member. The cutting insert includes a base member and a cutting member. The base member includes a first side surface, a second side surface, a third side surface, and a fourth side surface. The holder includes a front end surface, a rear end surface, and an outer peripheral surface. The holder is provided with a first hole and a second hole. The first hole is opened in the front end surface. The second hole is opened in the outer peripheral surface. The holder includes a stopper. A surface defining the second hole includes a first inner side surface and a second inner side surface. The pressing member is in contact with the fourth side surface in a state in which the pressing member is disposed in the first hole.

Abstract: A cutting insert includes a first surface, a second surface, and an outer peripheral side surface. A ridgeline between the first surface and the outer peripheral side surface forms a first ridgeline. A ridgeline between the second surface and the outer peripheral side surface forms a second ridgeline. The first ridgeline includes a first straight portion, a first wiper edge, a first corner cutting edge, and a second straight portion. The second ridgeline includes a third straight portion, a second wiper edge, a second corner cutting edge, and a fourth straight portion. The outer peripheral side surface includes a first wiper flank surface, a first corner flank surface, a second wiper flank surface, a second corner flank surface, a first plane, and a second plane. The first plane is contiguous to each of the first corner flank surface and the second wiper flank surface.

Abstract: A cutting insert has a top surface, a bottom surface, and an outer peripheral surface. A ridgeline between the top surface and the outer peripheral surface includes a first cutting edge. A protrusion is provided on the top surface. In a first cross section, a distance between the first cutting edge and the protrusion in a direction perpendicular to the bottom surface is defined as a first distance. In a second cross section, a distance between the first cutting edge and the protrusion in a direction perpendicular to the bottom surface is defined as a third distance. The third distance is longer than the first distance. A ratio of a height of the protrusion to a width of the protrusion in the second cross section is smaller than a ratio of a height of the protrusion to a width of the protrusion in the first cross section.

Abstract: The boundary flow path is constituted of a pair of boundary wall surfaces facing each other in a first cross section intersecting each of the first flow path, the boundary flow path, and the second flow path. An inclination of a tangent to at least one of the pair of boundary wall surfaces is continuously changed. In a second cross section perpendicular to a direction in which coolant flows, a lateral width of the first flow path is larger than a longitudinal width of the first flow path and a lateral width of the second flow path is larger than a longitudinal width of the second flow path when a longitudinal direction represents a direction in which the pair of boundary wall surfaces face each other and a lateral direction represents a direction perpendicular to the longitudinal direction.

Abstract: A cutting insert includes a first surface, a second surface, and an outer peripheral side surface. A ridgeline between the first surface and the outer peripheral side surface forms a first ridgeline. A ridgeline between the second surface and the outer peripheral side surface forms a second ridgeline. The first ridgeline includes a first straight portion, a first wiper edge, a first corner cutting edge, and a second straight portion. The second ridgeline includes a third straight portion, a second wiper edge, a second corner cutting edge, and a fourth straight portion. The outer peripheral side surface includes a first wiper flank surface, a first corner flank surface, a second wiper flank surface, a second corner flank surface, a first plane, and a second plane. The first plane is contiguous to each of the first corner flank surface and the second wiper flank surface.

Abstract: A boring tool has a cutting insert, a holder, and a pressing member. The cutting insert includes a base member and a cutting member. The base member includes a first side surface, a second side surface, a third side surface, and a fourth side surface. The holder includes a front end surface, a rear end surface, and an outer peripheral surface. The holder is provided with a first hole and a second hole. The first hole is opened in the front end surface. The second hole is opened in the outer peripheral surface. The holder includes a stopper. A surface defining the second hole includes a first inner side surface and a second inner side surface. The pressing member is in contact with the fourth side surface in a state in which the pressing member is disposed in the first hole.

Abstract: The boundary flow path is constituted of a pair of boundary wall surfaces facing each other in a first cross section intersecting each of the first flow path, the boundary flow path, and the second flow path. An inclination of a tangent to at least one of the pair of boundary wall surfaces is continuously changed. In a second cross section perpendicular to a direction in which coolant flows, a lateral width of the first flow path is larger than a longitudinal width of the first flow path and a lateral width of the second flow path is larger than a longitudinal width of the second flow path when a longitudinal direction represents a direction in which the pair of boundary wall surfaces face each other and a lateral direction represents a direction perpendicular to the longitudinal direction.