Abstract: A cutting head rotatable about a central axis, comprising a tip portion and an intermediate portion. The tip portion has an axially forwardmost tip point contained in the central axis and three axially forward facing front surfaces forming three chisel edges extending axially rearwardly away from the tip point, each front surface having a radially extending cutting edge comprising a secondary cutting-edge portion extending radially outwardly from one of the chisel edges, and a primary cutting-edge portion extending radially outwardly therefrom. Each primary cutting-edge portion is contained in an imaginary annular ring surface having an annular ring width spanning at least radially inner and outer end points thereof. In a front-end view of the cutting head, each primary cutting-edge portion is concave, and radial planes intersect the imaginary annular surface to form imaginary rectilinear lines, each having a length equal to the annular ring width.

Abstract: A cutting head rotatable about a head axis has a cap portion and a rigid mounting protuberance joined to the cap portion. The cap portion has exactly four cutting portions circumferentially alternating with four head flutes and a head base surface facing in an axially rearward direction. The mounting protuberance extends axially rearwardly from the head base surface and has exactly two circumferentially spaced apart convex clamping surfaces. In a cross-section taken in a first horizontal plane perpendicular to the head axis and intersecting the mounting protuberance, only the two clamping surfaces are circumscribed by an imaginary first circle having a first diameter and a center coincident with the head axis. A rotary cutting tool has an elongated tool shank with a head receiving pocket at a forward end thereof and the cutting head of the type described above releasably secured to the head receiving pocket.

Abstract: A cutting head rotatable about a head axis has a cap portion and a rigid mounting protuberance joined to the cap portion. The cap portion has exactly four cutting portions circumferentially alternating with four head flutes and a head base surface facing in an axially rearward direction. The mounting protuberance extends axially rearwardly from the head base surface and has exactly two circumferentially spaced apart convex clamping surfaces. In a cross-section taken in a first horizontal plane perpendicular to the head axis and intersecting the mounting protuberance, only the two clamping surfaces are circumscribed by an imaginary first circle having a first diameter and a center coincident with the head axis. A rotary cutting tool has an elongated tool shank with a head receiving pocket at a forward end thereof and the cutting head of the type described above releasably secured to the head receiving pocket.

Abstract: A cutting head rotatable about a central axis, comprising a tip portion and an intermediate portion. The tip portion has an axially forwardmost tip point contained in the central axis and three axially forward facing front surfaces forming three chisel edges extending axially rearwardly away from the tip point, each front surface having a radially extending cutting edge comprising a secondary cutting-edge portion extending radially outwardly from one of the chisel edges, and a primary cutting-edge portion extending radially outwardly therefrom. Each primary cutting-edge portion is contained in an imaginary annular ring surface having an annular ring width spanning at least radially inner and outer end points thereof. In a front-end view of the cutting head, each primary cutting-edge portion is concave, and radial planes intersect the imaginary annular surface to form imaginary rectilinear lines, each having a length equal to the annular ring width.