Abstract: A cutting tool according to an aspect of the present invention is a cutting tool for cutting a rotationally symmetrical surface of a rotating workpiece. The cutting includes the step of feeding the cutting tool in a direction inclined with respect to a rotational axis of the rotationally symmetrical surface, while holding the cutting tool in contact with the rotationally symmetrical surface. In the step of feeding the cutting tool, the cutting tool has a point that is in contact with the rotationally symmetrical surface and the point shifts as the cutting tool is fed. The cutting tool includes: a rake face; a flank face; and a cutting edge connecting the rake face and the flank face. The cutting edge as seen from above the flank face has a shape including at least one arc, and the arc has a radius of curvature of not less than 100 mm and not more than 500 mm.

Abstract: The cutting edge has: a corner cutting edge; a flat cutting edge continuous to a first end portion of the corner cutting edge; and a main cutting edge continuous to a second end portion of the corner cutting edge opposite to the first end portion of the corner cutting edge. The rake face has: a first rising surface portion; and a first rake face portion continuous to the first rising surface portion and located opposite to the corner cutting edge when viewed from the first rising surface portion. When viewed in a direction perpendicular to the reference surface, the first boundary includes a first line segment extending, from one of the flat cutting edge and the corner cutting edge, in a direction crossing a straight line extending along the main cutting edge.

Abstract: A method of correcting a track of a cutting edge is provided. With movement of the cutting edge, a point on the cutting edge in contact with the rotation symmetry plane is moved along the cutting edge from a first end portion of the cutting edge to a second end portion of the cutting edge opposite to the first end portion. The correction method includes measuring, by a measurement unit, a shape of the cut and machined rotation symmetry plane, calculating, by an operation unit, an error of the measured shape of the rotation symmetry plane from a target shape of the rotation symmetry plane in a direction of the axial line of rotation, and correcting, by the operation unit, a component in the direction of the axial line of rotation of a track of a point of cutting based on the error.

Abstract: The edge portion includes an upper surface, a side surface, and a land surface. The side surface has a front side surface and a pair of lateral side surfaces. An intersection between the land surface and the front side surface forms a front cutting edge. An intersection between the land surface and each of the pair of lateral side surfaces form a corresponding one of a pair of lateral cutting edges. The edge portion contains 80 vol % or more of diamond. A chip breaker recess is provided between the upper surface and the land surface. The surfaces forming the chip breaker recess include a rake face and a breaker wall surface. The upper surface has a front edge portion opposite to the front cutting edge from the chip breaker recess. A pair of protruding portions are provided to extend from the front edge portion toward the front cutting edge.

Abstract: There is provided a throw-away tip which includes a blade containing diamond and is excellent in chip processability. The throw-away tip comprises a body and a blade provided to the body and having a cutting edge, the blade containing 80% by volume or more of diamond, the blade having a land surface extending along the cutting edge, and a chip breaker having a recess located opposite to the cutting edge with the land surface therebetween, the recess having a side surface having an inclined surface that recedes continuously as a distance thereof from the land surface increases in magnitude and that has a shape identical to that of a portion of a side surface of a shape of a body of revolution.

Abstract: There is provided a rotary tool including a rotary tool body and a blade provided to the rotary tool body and having a cutting edge, the blade containing 80% by volume or more of diamond, and the blade including a land surface extending along the cutting edge, and a chip breaker having a recess located opposite to the cutting edge with the land surface therebetween.

Abstract: A method includes positioning a linear cutting edge inclined at an angle greater than 0° and smaller than 90° with respect to a Z axis at a cutting start position displaced from a position on an X axis along a direction of a Y axis in a three-dimensional orthogonal coordinate system in which an axial line of rotation of a rotation symmetry plane is defined as the Z axis, an axis in a radial direction of the rotation symmetry plane is defined as the X axis, and an axis orthogonal to both of the Z axis and the X axis is defined as the Y axis and machining the rotation symmetry plane by feeding the cutting edge from the cutting start position along a track having an X axis component, a Y axis component, and a Z axis component while the cutting edge is in contact with a rotating machine component.

Abstract: A cutting tool for cutting a rotationally symmetrical surface of a rotating workpiece includes the step of feeding the cutting tool in a direction inclined with respect to a rotational axis of the rotationally symmetrical surface, while holding the cutting tool in contact with the rotationally symmetrical surface. In the step of feeding the cutting tool, the cutting tool has a point that is in contact with the rotationally symmetrical surface and the point shifts as the cutting tool is fed. The cutting tool includes: a rake face; a flank face; and a cutting edge connecting the rake face and the flank face. The cutting edge as seen from above the flank face has a shape including at least one arc, and the arc has a radius of curvature of not less than 100 mm and not more than 500 mm.

Abstract: A method for manufacturing a machine component having a rotation symmetry plane includes machining a rotation symmetry plane. The machining a rotation symmetry plane includes determining a track of the cutting. The determining a track determines the track in accordance with a condition that (1) a first end portion of the cutting edge is positioned at a cutting start position of the rotation symmetry plane, (2) N regions defined by division of the cutting edge successively come in contact with the rotation symmetry plane, (3) an inclination of a tangent line at a point of cutting of each of the N regions is equal to a target inclination of a tangent line which passes through the point of cutting and comes in contact with the rotation symmetry plane in a cut plane of the rotation symmetry plane, and (4) a second end of the cutting edge is positioned at a cutting end position of the rotation symmetry plane.

Abstract: There is provided a throw-away tip which includes a blade containing diamond and is excellent in chip processability. The throw-away tip comprises a body and a blade provided to the body and having a cutting edge, the blade containing 80% by volume or more of diamond, the blade having a land surface extending along the cutting edge, and a chip breaker having a recess located opposite to the cutting edge with the land surface therebetween, the recess having a side surface having an inclined surface that recedes continuously as a distance thereof from the land surface increases in magnitude and that has a shape identical to that of a portion of a side surface of a shape of a body of revolution.