A plurality of cutting edges that are arranged on an outer circumference of a shaft-shaped broach body are provided with a spline teeth group, which contains a plurality of spline teeth 8 that groove a prepared hole of a work material, and a round teeth group, which is disposed in a different position from the spline teeth group along an axis direction and contains a plurality of round teeth that machine an inner circumference of the prepared hole. At least one gullet is formed to extend along the outer circumference of the broach body in a circumferential direction around the axis between the round teeth that are adjacent to one another in the axis direction in the round teeth group. The gullet extends toward the axis direction, gradually twisting toward the circumferential direction. The spline teeth group and the round teeth group are formed integrally on the outer circumference of the broach body.

The tool holder device for broaching and slotting, comprising: one main frame associated with one machine adapted to machine one workpiece; one working assembly associated with the main frame and comprising one supporting bar movable longitudinally along a first axis and a guiding mechanism for the supporting bar movable longitudinally along the first axis; one tool associated with the supporting bar and adapted to machine the workpiece; angular adjustment mechanism for adjusting the supporting bar, interposed between the main frame and the guiding mechanism and adapted to rotate the supporting bar around a second axis substantially orthogonal with respect to the first axis; and straight adjustment mechanism for adjusting the tool with respect to the supporting bar, interposed between the tool and the supporting bar, the straight adjustment mechanism being adapted to adjust the position of the tool along the second axis.

Provided is a coated cutting tool that has a nitride hard coating that contains Ti at 70 at % to 95 at % and Si at 5 at % to 30 at % with respect to the total amount of metallic elements, and Ar at 0.05 at % to 0.20 at % with respect to the total amount of metallic and non-metallic elements, has a NaCl-type crystalline structure, exhibits maximum diffraction peak intensity in the (200) plane, and has an average grain size of 5 nm to 30 nm. When 100 at % is defined as the total of content rates of the metallic elements, nitrogen, oxygen, and carbon in a composition at intervals of 20 nm from a depth of 20 nm to 200 nm from a surface of the hard coating, the content rate of nitrogen is 50.0 at % or more.

An internal helical broaching tool has a pre-broaching tool portion extending in one broaching direction and a subsequent precise sizing tool portion. The latter, as a whole, is made of a hard metal with a density of greater than 10 g/cm3. This results in an internal helical broaching tool with increased service life at a defined machining performance.

A hard coating film of a coated cutting tool contains Al within a range of 70 at % to 80 at % and Ti within a range of 20 at % to 30 at % with respect to a total amount of metallic (including metalloid) elements, and contains Ar of 0.50 at % or less with respect to a total amount of the metallic elements (including metalloid) and nonmetallic elements. The film has a diffraction peak due to each of a TiN (111) plane, a TiN (200) plane, and a TiN (220) plane of an fcc structure and an AlN (100) plane and an AlN (002) plane of a hcp structure, in which the diffraction peak of the TiN (200) plane indicates a maximum intensity and an intensity of the diffraction peak due to the TiN (111) plane is next thereafter. The average crystal grain size is within a range of 5 nm to 50 nm.

A hard coating film of a coated cutting tool contains Al within a range of 70 at % to 80 at % and Ti within a range of 20 at % to 30 at % with respect to a total amount of metallic (including metalloid) elements, and contains Ar of 0.50 at % or less with respect to a total amount of the metallic elements (including metalloid) and nonmetallic elements. The film has a diffraction peak due to each of a TiN (111) plane, a TiN (200) plane, and a TiN (220) plane of an fcc structure and an AlN (100) plane and an AlN (002) plane of a hcp structure, in which the diffraction peak of the TiN (200) plane indicates a maximum intensity and an intensity of the diffraction peak due to the TiN (111) plane is next thereafter. The average crystal grain size is within a range of 5 nm to 50 nm.

Provided is a coated cutting tool that has a nitride hard coating that contains Ti at 70 at % to 95 at % and Si at 5 at % to 30 at % with respect to the total amount of metallic elements, and Ar at 0.05 at % to 0.20 at % with respect to the total amount of metallic and non-metallic elements, has a NaCl-type crystalline structure, exhibits maximum diffraction peak intensity in the (200) plane, and has an average grain size of 5 nm to 30 nm. When 100 at % is defined as the total of content rates of the metallic elements, nitrogen, oxygen, and carbon in a composition at intervals of 20 nm from a depth of 20 nm to 200 nm from a surface of the hard coating, the content rate of nitrogen is 50.0 at % or more.

A cutting element for a tool to create a helically extending, trapezoidally undercut groove in a cylindrical surface of a bore. The cutting tool, preferably configured as a cutting insert, has groove-cutting teeth to create a symmetrically cross-sectioned groove which are arranged in series in a division harmonized with the pitch of the groove to be created. These groove-cutting teeth comprise at least one pre-machining tooth to create and machine a base groove and several trapezoidal teeth following the at least one pre-machining tooth, which have a tooth head profile which expands trapezoidally in cross-section in the vertical direction of the tooth with two flanks delimiting a flank angle for further machining the base groove to a trapezoidally undercut final cross-section. The flank angle delimited by the two flanks increases from at least one trapezoidal tooth to a following trapezoidal tooth to a defined final dimension.

A hard coating film of a coated cutting tool contains Al within a range of 70 at % to 80 at % and Ti within a range of 20 at % to 30 at % with respect to a total amount of metallic (including metalloid) elements, and contains Ar of 0.50 at % or less with respect to a total amount of the metallic elements (including metalloid) and nonmetallic elements. The film has a diffraction peak due to each of a TiN (111) plane, a TiN (200) plane, and a TiN (220) plane of an fcc structure and an AlN (100) plane and an AlN (002) plane of a hcp structure, in which the diffraction peak of the TiN (200) plane indicates a maximum intensity and an intensity of the diffraction peak due to the TiN (111) plane is next thereafter. The average crystal grain size is within a range of 5 nm to 50 nm.

A hard coating film of a coated cutting tool contains Al within a range of 70 at % to 80 at % and Ti within a range of 20 at % to 30 at % with respect to a total amount of metallic (including metalloid) elements, and contains Ar of 0.50 at % or less with respect to a total amount of the metallic elements (including metalloid) and nonmetallic elements. The film has a diffraction peak due to each of a TiN (111) plane, a TiN (200) plane, and a TiN (220) plane of an fcc structure and an AlN (100) plane and an AlN (002) plane of a hcp structure, in which the diffraction peak of the TiN (200) plane indicates a maximum intensity and an intensity of the diffraction peak due to the TiN (111) plane is next thereafter. The average crystal grain size is within a range of 5 nm to 50 nm.