A modular rotary cutting tool for conducting cutting operations on a work piece is described. The modular rotary cutting tool includes a tool shank having a pocket and a cutting head replaceably mounted in the pocket of the tool shank. The cutting head has a leading end and trailing end opposite the leading end. The drilling portion extends from the leading end of the modular rotary cutting tool to the reaming portion. The reaming portion extends from the drilling portion to a coupling portion of the cutting head. The coupling portion extends from the reaming portion to the trailing end of the cutting head.

A cutting tool may include a circular columnar body extending from a first end to a second end along a rotation axis. At least a part of the columnar body may correspond to an insert including a cutting edge at the first end. The insert may include therein a flow path extending from a side of the first end toward a side of the second end. A width of the flow path along a radial direction of the circular columnar body may be smaller than a width of the flow path along a circumferential direction of the circular columnar body in a cross section orthogonal to the rotation axis.

A cutting tool may include a circular columnar body extending from a first end to a second end along a rotation axis. At least a part of the columnar body may correspond to an insert including a cutting edge at the first end. The insert may include therein a flow path extending from a side of the first end toward a side of the second end. A width of the flow path along a radial direction of the circular columnar body may be smaller than a width of the flow path along a circumferential direction of the circular columnar body in a cross section orthogonal to the rotation axis.

Described herein is a first method of forming a hole in a workpiece, having a first surface and a second surface opposite the first surface. The method includes forming a first hole, having a first diameter, in the workpiece by passing a first cutter through the workpiece from the first surface to the second surface. Additionally, the method includes forming a chamfer in the second surface of the workpiece concentric with the first hole using a second cutter. The chamfer has a second diameter larger than the first diameter. The method further includes forming a second hole, having a third diameter larger than the first diameter, in the workpiece concentric with the first hole by passing a third cutter through the workpiece from the first surface to the second surface.

Described herein is a first method of forming a hole in a workpiece, having a first surface and a second surface opposite the first surface. The method includes forming a first hole, having a first diameter, in the workpiece by passing a first cutter through the workpiece from the first surface to the second surface. Additionally, the method includes forming a chamfer in the second surface of the workpiece concentric with the first hole using a second cutter. The chamfer has a second diameter larger than the first diameter. The method further includes forming a second hole, having a third diameter larger than the first diameter, in the workpiece concentric with the first hole by passing a third cutter through the workpiece from the first surface to the second surface.

A process for producing a tool having a main body which extends in a longitudinal direction and at least one blade for machining a workpiece includes providing a base coating on the tool; grinding the at least one blade in a manner that removes the base coating in the region of the at least one blade; and providing a second, fine coating, to the at least one ground blade.

A process for producing a tool having a main body which extends in a longitudinal direction and at least one blade for machining a workpiece includes providing a base coating on the tool; grinding the at least one blade in a manner that removes the base coating in the region of the at least one blade; and providing a second, fine coating, to the at least one ground blade.

A machining tool for use in machine tools for rotating cutting operations has a main body, which can be rotated about a center axis and which is elongate in the direction of the center axis, at least one cutting element fastened to the main body and at least one chip removal channel, which extends along the main body outside of the center axis and which is bounded inwardly by a core of the main body, through which core the center axis passes. The chip removal channel is outwardly closed at least over a longitudinal section by an outer chip space wall adjoining the core.

A surface-coated cutting tool includes a substrate and a coating that is disposed on the substrate and formed so as to cover at least a portion of a flank face, in which the coating includes an inner layer and an outer layer formed on the inner layer, the inner layer is formed of at least one layer and includes an aluminum oxide layer as a layer in contact with the outer layer, the outer layer has a multilayer structure that includes three or more layers stacked on top of one another, and each of the layers that constitute the multilayer structure contains titanium.

A cutting tool includes a substrate and a coating film provided on the substrate, wherein the substrate is a cBN sintered material including more than or equal to 30 volume % and less than 80 volume % of cBN and a binder, the coating film includes a compound layer constituted of a composition of Ti.sub.1-xAl.sub.xC.sub.1-aN.sub.a, where 0.70X0.95 and 0<a1, and the compound layer has a NaCl type crystal structure in a whole or part of the compound layer.