A cutting head rotatable about a central axis, includes a tip portion and an intermediate portion. The tip portion has an axially forwardmost tip point contained in the central axis and at least two axially forward-facing front surfaces, each front surface having a radially extending cutting edge. The intermediate portion has at least two head lands circumferentially alternating with at least two chip evacuation passages, each head land having a leading edge extending axially rearwardly from the tip portion. The cutting edges are contained in an imaginary annular ring surface, and a first imaginary radial plane containing the central axis intersects the imaginary annular ring surface to form two imaginary radial cutting profiles. Each imaginary radial cutting profile has consecutively radially outward extending first, second, and third cutting profile portions, and the second cutting profile portion includes first and second concave sub-portions spaced apart by a first convex sub-portion.

A tool for generating a threaded hole is rotatable in a rotational movement about a tool axis extending through the tool, and is movable in an axial forward direction axially of the tool axis. The tool comprises at least one thread generation area and at least one drilling area, which are rigidly motion-coupled to each other. The drilling area is provided for generating a core hole and is arranged axially offset to the tool axis with respect to the thread generation area. The thread generation area projects radially to the tool axis, runs along a helical line, and a predetermined winding sense of the thread to be generated, and has a working profile which corresponds to the thread profile of the thread to be generated. The drilling area has a drilling edge, and at least one chip divider is arranged on the drilling edge, interrupts the drilling edge.

The negative land includes: a first region in which a space between the upper cutting edge and the lower cutting edge becomes wider toward the outer circumferential surface; and a second region which is continuous to the first region and in which the space becomes wider toward the rotation axis. In a cross section perpendicular to the rotation axis, the rake face includes a return face continuous to the outer circumferential surface, the return face being recessed opposite to a rotation direction of the drill. When a first boundary represents a boundary between the outer circumferential surface and the first region and a second boundary represents a boundary between the first region and the second region, a length of the first boundary is larger than a length of the second boundary in a direction parallel to the rotation axis. The second boundary is continuous to the return face.

The negative land includes: a first region in which a space between the upper cutting edge and the lower cutting edge becomes wider toward the outer circumferential surface; and a second region which is continuous to the first region and in which the space becomes wider toward the rotation axis. In a cross section perpendicular to the rotation axis, the rake face includes a return face continuous to the outer circumferential surface, the return face being recessed opposite to a rotation direction of the drill. When a first boundary represents a boundary between the outer circumferential surface and the first region and a second boundary represents a boundary between the first region and the second region, a length of the first boundary is larger than a length of the second boundary in a direction parallel to the rotation axis. The second boundary is continuous to the return face.

A cutting head rotatable about a central axis, includes a tip portion and an intermediate portion. The tip portion has an axially forwardmost tip point contained in the central axis and at least two axially forward-facing front surfaces, each front surface having a radially extending cutting edge. The intermediate portion has at least two head lands circumferentially alternating with at least two chip evacuation passages, each head land having a leading edge extending axially rearwardly from the tip portion. The cutting edges are contained in an imaginary annular ring surface, and a first imaginary radial plane containing the central axis intersects the imaginary annular ring surface to form two imaginary radial cutting profiles. Each imaginary radial cutting profile has consecutively radially outward extending first, second, and third cutting profile portions, and the second cutting profile portion includes first and second concave sub-portions spaced apart by a first convex sub-portion.

The present disclosure relates to cutting tools and cutting inserts in general, and more particularly to the specific shapes of cutting edges on cutting tools and cutting inserts. In an embodiment, a cutting tool with a cutting edge formed as a sinusoidal curve is provided. In an embodiment, a rotary drill bit including a cutting insert comprising a sinusoidal curve is provided.

The present disclosure relates to cutting tools and cutting inserts in general, and more particularly to the specific shapes of cutting edges on cutting tools and cutting inserts. In an embodiment, a cutting tool with a cutting edge formed as a sinusoidal curve is provided. In an embodiment, a rotary drill bit including a cutting insert comprising a sinusoidal curve is provided.

A spirally-fed drilling and milling cutter to be driven spirally in order to drill and mill includes a shank, a groove at one of a plurality of offset positions at one end of the shank, a blade at a bottom side of the groove, and a spiral flute on the periphery of the main body of the shank, wherein the spiral flute has a flute end connected with the groove. When the cutter is rotated at high speed and in high torsion, drilling/milling chips are pushed upward, along with a cutting liquid, through the spiral flute out of a hole being made. Thus, the heat generated by the cutting action is reduced, and the chips are efficiently discharged, allowing the cutting edges to stay sharp and the cutter to make deep holes.

Methods of forming a drill bit or boring tool having a cutting edge that includes a pair of generally smooth curvilinear shaped portions that are positioned near the radial outer portions of the cutting edge and connected to one another by a pair of generally linear portions that traverse a longitudinal centerline of the tool.

A drill bit or boring tool having cutting edge that includes a pair of generally smooth curvilinear shaped portions that are positioned near the radial outer portions of the cutting edge and connected to one another by a pair of generally linear portions that traverse the longitudinal centerline of the tool.