A cutting tool, including: a base; and a coating disposed on the base, wherein the coating includes a first layer, the first layer is composed of an alternate layer in which a first unit layer and a second unit layer are alternately stacked, the first unit layer has a hexagonal crystal structure, the first unit layer is composed of W(C.sub.1-aN.sub.a).sub.x, a represents 0.3 or more and 0.8 or less, x represents 0.8 or more and 1.2 or less, the second unit layer is composed of Al.sub.cCr.sub.1-cN, and c represents 0.40 or more and 0.80 or less.

A work holder includes: a first holding part having three attracting members that are arranged circumferentially apart from each other to attract an axial end face of an annular work; and a second holding part having a contacting member that is held in contact with an inner periphery or outer periphery of the work and restricts radial movement of the work.

A cutting tool, including: a base; and a coating disposed on the base, wherein the coating includes a first layer, the first layer is composed of an alternate layer in which a first unit layer and a second unit layer are alternately stacked, the first unit layer has a hexagonal crystal structure, the first unit layer is composed of W(C.sub.1-aN.sub.a).sub.x, a represents 0.3 or more and 0.8 or less, x represents 0.8 or more and 1.2 or less, the second unit layer is composed of Al.sub.cCr.sub.1-cN, and c represents 0.40 or more and 0.80 or less.

A constant rake planar cutting edge fluted drill bit and a method of manufacturing the same. The drill bit includes a planar cutting face formed at the tip end of the bit by a motion of a rotating machining wheel respective to a stationary blank in a first step. Once the cutting face is formed, the blank is rotated and translated in a direction parallel to an elongated axis, during which the rotating machining wheel creates a flute. Upon completion of the first flute, the bit is rotated accordingly and the processes are repeated to create each subsequent planar cutting face and respective flute. The process can also be completed in a slightly modified version of a reverse process, fabricating a flute prior to formation of the planar cutting face of the bit.

A rotary tool for machining workpieces, comprising at least one main body with a clamping segment, a tool head comprising a cutting region, and at least one coolant channel for feeding a cooling and lubricating fluid into the cutting region. At least one partial surface section of the cutting region forms a hardened region, which covers and/or defines the coolant channel and is surface-hardened. A method for producing a rotary tool.

A dual tip cutter (10) includes a body (12) defining a feed direction (F), a cutting direction (C) perpendicular to the feed direction, and a depth direction (D) perpendicular to both feed and cutting directions. A first cutting portion (35) is fixed relative to the body at a body first end. A second cutting portion (45) is fixed relative to the body at the body first end, adjacent the first cutting portion. The first and second cutting portions are stacked in the cutting direction so that the first cutting portion forms a leading cutting portion and the second cutting portion forms a trailing cutting portion for simultaneous cutting. The second cutting portion extends from the body further in the depth direction than the first cutting portion. A relative position between the first and second cutting portions is set such that a total chip load is shared between the first and second cutting portions in a predetermined ratio (K).

To provide a cutting tool that includes a coating layer capable of exhibiting optimum cutting performance in each of a cutting edge, rake face, and flank face. A cutting tool (1) includes a substrate (2) that is coated with a coating layer (6) composed of Si.sub.aM.sub.1-a(C.sub.1-xN.sub.x), where M represents at least one element selected from Ti, Al, Cr, W, Mo, Ta, Hf, Nb, Zr, and Y, 0.01a0.4, and 0x1, and that has a cutting edge (5) at an intersecting ridge line of a rake face (3) and a flank face (4). The Si content ratio in the coating layer (6) on the rake face (3) is higher than that on the cutting edge (5).

An assembly-type cutter includes a shank and a cutter head. The shank has a hole at one end. The hole has a receiving portion, which includes an internal thread and can be treated thermally for increased rigidity. The cutter head has a cutting portion and a connecting portion at opposite ends respectively. The connecting portion includes a threaded member and can also be treated thermally for increased rigidity. The cutter head and the shank are threadedly connectable via the connecting portion and the receiving portion. The threaded member includes a body portion, whose diameter is defined as a root diameter, and an external thread on the body portion. The body portion is slightly tapered such that a locus of the root diameter is inclined.

A compound sintered body contains cubic boron nitride particles and binder particles. The composite sintered body contains 40 vol % or more and 80 vol % or less of the cubic boron nitride particles. The binder particles contain TiCN particles. The composite sintered body shows a first peak belonging to a (200) plane of the TiCN particles in a range in which a Bragg angle 2 is 41.7 or more and 42.6 or less in an X-ray diffraction spectrum measured using a Cu-K ray as a ray source.

Methods of machining a body to produce a chip are provided wherein the body is formed of a material and in a state such that the material exhibits sinuous flow during a machining operation. The methods include providing a layer located on a surface of the body, and machining the body by causing engagement between a cutting tool and the body in a contact region below an area of the surface having the coating layer thereon and moving the cutting tool relative to the body to produce the chip having the layer thereon. The layer reduces sinuous flow in the material of the body and the chip is formed primarily by laminar flow.