A rotary cutting tool. The tool has a body with outside diameter (OD), and outer surface, and a longitudinal axis, a plurality of flutes, helical in some embodiments. Flutes include a narrow leading edge land portion with circular segment profile and having flute cutting edge portions along a substantially uniform circumferential location, with an eccentric relief margin rotationally rearward of the narrow leading edge land portions. Face portions are provided with face cutting edge portions, and with a first dish portion adjacent each of the cutting edge portions sloping inwardly and downwardly generally toward a central longitudinal axis at a first dish angle alpha () Corner blend portions extend from flute cutting edge portions to the face cutting edge portions. Corner blend portions are provided in a variety of profiles, including an embodiment wherein the profile of the corner blend portions are truncated before the segment of curvature becomes tangential to the face cutting edge portions. Large core diameters of cutting tools are provided, which gives high strength at when working with axial depths of cut of about three times outside tool diameter or less.

A hard lubrication film, with which a surface of a base material is coated, has two or more alternately laminated layers that are one or more A-layers made of (Cr.sub.aMo.sub.bW.sub.cV.sub.dB.sub.e).sub.1x.sub.yC.sub.xN.sub.y and one or more B-layers made of (Cr.sub.aMo.sub.bW.sub.cV.sub.dB.sub.e).sub.1xyzC.sub.xN.sub.yO.sub.z. Atom ratios a, b, c, d, e=1abcd, x+y, and y related to A-layers satisfy 0.2a0.7, 0.05b0.6, 0c0.3, 0d0.05, 0e0.05, 0.3x+y0.6, and 0y0.6, respectively. Atom ratios a, b, c, d, e=1abcd, x, y, z, and x+y+z related to B-layers satisfy 0.2a0.7, 0.05b0.6, 0c0.3, 0d0.05, 0e0.05, 0x0.6, 0y0.6, 0<z0.6, and 0.3x+y+z0.6, respectively. Each A-layer has a film thickness within a range of 2 nm or more to 1000 nm or less, each B-layer has a film thickness within a range of 2 nm or more to 500 nm or less, and wherein the hard lubrication film has a total film thickness within a range of 0.1 m or more to 10.0 m or less.

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.

The present disclosure relates to a cutting tool of a cemented carbide substrate including WC and a binder phase having one or more of Co, Fe and Ni, wherein the cemented carbide also includes a finely dispersed eta phase of Me12C and/or Me6C carbides, where Me is one or more metals selected from W, Mo and the binder phase metals, wherein the substoichiometric carbon content in the cemented carbide is between 0.30 to 0.16 wt %. The disclosed cutting tool will achieve an improved resistance against comb cracks.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The coating includes an -Al.sub.2O.sub.3 layer. The -Al.sub.2O.sub.3 layer contains -Al.sub.2O.sub.3 crystal grains and sulfur, and has a TC(006) of more than 5 in texture coefficient TC(hkl). The sulfur has a concentration distribution in which a concentration of the sulfur decreases in a direction away from a base-material-side surface of the -Al.sub.2O.sub.3 layer, in a thickness direction of the -Al.sub.2O.sub.3 layer.

The present invention provides a more practical hard-coated cutting tool having improved cutting performance during finishing so as to obtain a better finished surface. Provided is a hard-coated cutting tool including a tool body (7) coated with a hard coating (4) and having a cutting edge (3) formed on a ridge line intersecting a flank face (1) and a rake face (2). In the hard-coated cutting tool, the thickness h1 of the hard coating (4) on the flank face (1) side and the thickness h2 of the hard coating (4) on the rake face (2) side near the cutting edge (3) satisfies conditions 8 mh130 m and 0h2/h10.5 in a cross-section perpendicular to the cutting edge (3) in a range equal to or less than 0.3 times the tool diameter in the axial direction from the tip of the tool.

A surface-coated cutting tool includes a base material and a coating formed on the base material. The coating includes an -Al.sub.2O.sub.3 layer. The -Al.sub.2O.sub.3 layer contains -Al.sub.2O.sub.3 crystal grains and sulfur, and has a TC(006) of more than 5 in texture coefficient TC(hkl). The sulfur has a concentration distribution in which a concentration of the sulfur decreases in a direction away from a base-material-side surface of the -Al.sub.2O.sub.3 layer, in a thickness direction of the -Al.sub.2O.sub.3 layer.

One aspect of the disclosure relates to a cutting tool for forming a final opening in a stack that includes at least two layers and a pilot opening having a pilot-opening dimension and extending through at least one of the at least two layers. The cutting tool includes a shank. The cutting tool also includes a first portion including at least one of a first coating or the first coating and a second coating, wherein the first coating at least partially covers the first portion. The cutting tool also includes a second portion between the shank and the first portion, wherein the second portion includes the second coating, and wherein the second coating at least partially covers the second portion.

Herein is provided a method of milling a brittle workpiece (46) using a milling tool (10), the workpiece (46) comprising a material, the material having a Ductile-Brittle Transition Undeformed Chip Thickness, DBh.sub.rn, the milling tool (10) comprising a tool shank (12) having an axis of rotation (14), and further comprising a tool head (16) comprising superhard material at one end thereof, the tool head (16) having a diameter (42), and operating the milling tool (10) such that an Undeformed Chip Thickness, h.sub.m, of the workpiece (46) is less than said Ductile-Brittle Transition Undeformed Chip Thickness, DBh.sub.m of the material.

Provided are: a hard lubricating coating film which is hard and has wear resistance; and a hard lubricating coating film-covered tool. A hard coating film (10), which is hard and has wear resistance, and an end mill (12) can be obtained by alternately forming two or more (CraMobWcVdBe)1-x-yCxNy layers A (22) and two or more (CraMobWcVdBe)1-x-y-zCxNyOz layers B (24) by controlling the composition ratios of Cr, Mo, W, V and B and various reaction gases during the film formation, or alternatively by controlling only the various reaction gases during the film formation. In this connection, the atomic ratios a-e, y and (x+y) of the layers A (22) are within predetermined ranges; the atomic ratios a-e, x, y, z and (x+y+z) of the layers B (24) are within predetermined ranges; the film thickness (D1) of the layers A (22) is within the range from 2 nm to 1,000 nm (inclusive); the film thickness (D2) of the layers B (24) is within the range from 2 nm to 500 nm (inclusive); and the total film thickness (D) is within the range from 0.1 m to 10.0 m (inclusive).