A method for manufacturing a roll mold by cutting a roll, includes generating a control waveform based on a signal corresponding to a rotary position of the roll, and making a plurality of cuts on a surface of the roll by, while the roll is rotated, reciprocating a cutting blade in a radial direction of the roll in accordance with the control waveform. Making the plurality of cuts includes at each of a plurality of predetermined locations, making a predetermined number of cuts of predetermined depth based on the control waveform. Generating the control waveform includes generating a control waveform dictating that, when multiple cuts are made at a predetermined location, each subsequent cut will have a smaller depth than a preceding cut.

A cutting tool rotates about a rotation axis, and includes a tip end portion. The tip end portion includes a partially spherical surface that is brought into contact with a workpiece. The surface is provided with a plurality of recesses disposed apart from each other. An opening edge of each of the plurality of recesses constitutes a cutting edge.

Disclosed is a mounting device (6) including a receiving opening (8) with a circular inner locating surface (10) which is coaxial with the axis of rotation (3) and serves for engagement with radially outer vertices (24) of the polygon profile of a holding pin (23). Arranged adjacent to the inner locating surface is a positioning disk (14) which has an opening (15) coaxial with the axis of rotation (3) and of such polygonal shape and size that the polygon profile of the holding pin (23) engaging in the opening (15) is supported in the opening (15) in a manner preventing relative rotation.

A collet-type mechanism for releasably gripping either an external or internal target surface of a tubular workpiece includes a collet receiver defining a collet receiver contact surface configured as a curved lateral surface of a truncated right circular cone, and a segmented collet assembly comprising a plurality of collet segments. Each collet segment defines a workpiece engagement surface configured for gripping engagement with a workpiece target surface, and a collet segment contact surface configured for at least partial contacting engagement with the collet receiver contact surface. The collet segment contact surface may comprise two axially-contiguous regions, one of which corresponds to a curved lateral surface of either an oblique circular cylinder or a right circular cylinder, and the other of which corresponds to a curved lateral surface of a truncated right circular cone.

A rotary tool may include a base. The base may be extended from a first end to a second end. The base may include a first part and a second part. The first part may include the first end. The second part may have a larger outer diameter than the first part. The first part may include a first flute. The second part may include a second flute. In a first cross section of the first part, the first flute may include a first bottom part. A center of a first imaginary circle overlapping with the first bottom part may be located outside a circumscribed circle of the first part. In a second cross section of the second part, the second flute may include a second bottom part. A center of the second imaginary circle overlapping with the second bottom part may be located inside a circumscribed circle of the second part.

A hole saw including a plurality of sidewall openings is provided. The sidewall openings are shaped and grouped in patterns that improve debris ejection of the hole saw, and that allows for easy access to the interior of the hole saw for manual debris removal by the user. The opening groups are space from each other by larger uninterrupted areas such that the hole saw has a high strength despite the number and size of openings provided in the saw sidewall.

A collet-type mechanism for releasably gripping either an external or internal target surface of a tubular workpiece includes a collet receiver defining a collet receiver contact surface configured as a curved lateral surface of a truncated right circular cone, and a segmented collet assembly comprising a plurality of collet segments. Each collet segment defines a workpiece engagement surface configured for gripping engagement with a workpiece target surface, and a collet segment contact surface configured for at least partial contacting engagement with the collet receiver contact surface. The collet segment contact surface may comprise two axially-contiguous regions, one of which corresponds to a curved lateral surface of either an oblique circular cylinder or a right circular cylinder, and the other of which corresponds to a curved lateral surface of a truncated right circular cone.

A hole saw including a plurality of sidewall openings is provided. The sidewall openings are shaped and grouped in patterns that improve debris ejection of the hole saw, and that allows for easy access to the interior of the hole saw for manual debris removal by the user. The opening groups are space from each other by larger uninterrupted areas such that the hole saw has a high strength despite the number and size of openings provided in the saw sidewall.

A cutting tool rotates about a rotation axis, and includes a tip end portion. The tip end portion includes a partially spherical surface that is brought into contact with a workpiece. The surface is provided with a plurality of recesses disposed apart from each other. An opening edge of each of the plurality of recesses constitutes a cutting edge.