A cutting tool includes: a body extending along a longitudinal axis between a leading and trailing ends, the body having a clamping region disposed at or about the trailing end and a cutting region which extends toward the clamping region from the leading end of the body; a plurality of flutes defined in the body, each extending from the leading end toward the coupling portion; a plurality of peripheral cutting edges, each extending from the leading end toward the coupling portion along a corresponding flute of the plurality of flutes; and a plurality of end cutting edges disposed at the leading end, each end cutting edge extending from at or near the longitudinal axis outward along a corresponding flute. At least one end cutting edge is defined, in-part, by a plurality of rake faces which each extend from a corresponding portion of the one cutting edge into the corresponding flute.

A cutting tool includes: a body extending along a longitudinal axis between a leading and trailing ends, the body having a clamping region disposed at or about the trailing end and a cutting region which extends toward the clamping region from the leading end of the body; a plurality of flutes defined in the body, each extending from the leading end toward the coupling portion; a plurality of peripheral cutting edges, each extending from the leading end toward the coupling portion along a corresponding flute of the plurality of flutes; and a plurality of end cutting edges disposed at the leading end, each end cutting edge extending from at or near the longitudinal axis outward along a corresponding flute. At least one end cutting edge is defined, in-part, by a plurality of rake faces which each extend from a corresponding portion of the one cutting edge into the corresponding flute.

A cutting insert includes a rake face, a flank surface, and a cutting edge, the cutting edge includes a bottom cutting edge that is positioned at a front end in a central axis direction and forms a convex arc shape and an outer peripheral cutting edge aligned with a radial-direction outer end of the bottom cutting edge and forms a convex arc shape of which a curvature radius is larger than that of the bottom cutting edge, an angle formed between a tangent line to a boundary point between the bottom cutting edge and the outer peripheral cutting edge and the central axis is less than 45, a curvature radius R1 of the bottom cutting edge is 0.3 to 10 mm, and a ratio (R2/R1) of a curvature radius R2 of the outer peripheral cutting edge to the curvature radius R1 of the bottom cutting edge is 3.6 to 333.

A cutting insert includes a rake face, a flank surface, and a cutting edge, the cutting edge includes a bottom cutting edge that is positioned at a front end in a central axis direction and forms a convex arc shape and an outer peripheral cutting edge aligned with a radial-direction outer end of the bottom cutting edge and forms a convex arc shape of which a curvature radius is larger than that of the bottom cutting edge, an angle formed between a tangent line to a boundary point between the bottom cutting edge and the outer peripheral cutting edge and the central axis is less than 45, a curvature radius R1 of the bottom cutting edge is 0.3 to 10 mm, and a ratio (R2/R1) of a curvature radius R2 of the outer peripheral cutting edge to the curvature radius R1 of the bottom cutting edge is 3.6 to 333.

Disclosed is a tool for processing an engine block. The tool for processing the engine block includes: multiple cutting inserts; and main cutting edges which are formed at end portions of the inserts, respectively, in which the main cutting edge has a positive axial inclination angle and a radial inclination angle of 5 degrees to 0 degree.

In a formed end mill, a peripheral cutting edge has a smaller-diameter cutting part and a larger-diameter cutting part. An imaginary line obtained by lining up a deepest point of a flute bottom of a chip discharge flute, which appears in a cross-sectional view perpendicular to an axis of an end mill body, in an extending direction of the chip discharge flute is defined as a virtual flute bottom line. A flute helix angle, which is formed between the virtual flute bottom line and the axis, in a side view when the end mill body is seen from a radial direction orthogonal to the axis, is 0 degrees or more at a distal end part of the chip discharge flute in the axial direction, and increases gradually from the distal end part toward a posterior end in the axial direction.

A milling cutter includes a shank and a cutting head attached to the shank. The cutting head has a plurality of helical teeth, each tooth including a cutting tip, a leading face and a rear face. A flute is defined between the leading face of a trailing tooth, and a rear face of an immediately preceding tooth. A gully of the flute has a flute base with a portion that is planar or convex in profile to provide additional volume for effective chip evacuation. A method for manufacturing the milling cutter includes rotating a cylindrical blank about its own longitudinal axis, rotating a disc-shaped flute grinding wheel) about a rotational axis of a flute wheel and moving the grinding wheel in a longitudinal direction so as to form the helical flute with the gully having the flute base with the planar or convex portion in profile.