Abstract: A method for manufacturing a cubic boron nitride cutting tool including a base metal and sintered cubic boron nitride compact at a corner portion of the base metal, capable of improving the accuracy of the center height and reducing the angle of inclination or width of a negative rake face; and the cubic boron nitride cutting tool. The method includes grinding the compact by pressing it against an end face of a grindstone of a grinder to form flank and rake faces on the compact while the base metal of the cutting tool is held by a chuck of the grinder, so that the compact is substantially ground. The rake face is formed to be recessed from a top face of the base metal or only a portion of the compact that protrudes from a base-metal rake face is ground while the tool is continuously held by the chuck.

Abstract: A cutting tool includes a cutting insert that is held in a holder in a detachable manner. The cutting insert has a substantially regular quadrangular shape in plan view and includes four round corners. The cutting insert is formed of CBN sinter as a whole. The cutting insert includes two principal surfaces that are upper and lower surfaces opposite to each other, and four side surfaces that are arranged so as to connect the principal surfaces to each other. A boundary portion (ridge line portion) between each of the principal surfaces and each of the side surfaces forms a cutting edge. In a central portion of each of the side surfaces of the cutting insert, a groove for absorbing a crack, having a substantially V-shape in cross section, is formed all around the cutting insert so as to be recessed with respect to the side surfaces.

Abstract: A cutting tool includes a cutting insert that is held in a holder in a detachable manner. The cutting insert has a substantially regular quadrangular shape in plan view and includes four round corners. The cutting insert is formed of CBN sinter as a whole. The cutting insert includes two principal surfaces that are upper and lower surfaces opposite to each other, and four side surfaces that are arranged so as to connect the principal surfaces to each other. A boundary portion (ridge line portion) between each of the principal surfaces and each of the side surfaces forms a cutting edge. In a central portion of each of the side surfaces of the cutting insert, a groove for absorbing a crack, having a substantially V-shape in cross section, is formed all around the cutting insert so as to be recessed with respect to the side surfaces.

Abstract: A method for manufacturing a cubic boron nitride cutting tool including a base metal and sintered cubic boron nitride compact at a corner portion of the base metal, capable of improving the accuracy of the center height and reducing the angle of inclination or width of a negative rake face; and the cubic boron nitride cutting tool. The method includes grinding the compact by pressing it against an end face of a grindstone of a grinder to form flank and rake faces on the compact while the base metal of the cutting tool is held by a chuck of the grinder, so that the compact is substantially ground. The rake face is formed to be recessed from a top face of the base metal or only a portion of the compact that protrudes from a base-metal rake face is ground while the tool is continuously held by the chuck.