A drill head for deep-hole drilling includes cutting blade tips brazed to cutting chip discharge ports opened on a head distal end surface, guide pads mounted on a plurality of positions of the circumferential surface at the head distal end side, and a hollow inside portion made into a cutting chip discharge passage communicating with the cutting chip discharge ports. A guide pad portion having an arc surf ace that slide-contacts with the inner circumference of a cutting hole is formed on the outer end surface of the circumferential portion cutting blade tip.

A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.

A drill head for deep-hole drilling includes cutting blade tips brazed to cutting chip discharge ports opened on a head distal end surface, guide pads mounted on a plurality of positions of the circumferential surface at the head distal end side, and a hollow inside portion made into a cutting chip discharge passage communicating with the cutting chip discharge ports. A guide pad portion having an arc surface that slide-contacts with the inner circumference of a cutting hole is formed on the outer end surface of the circumferential portion cutting blade tip.

A rotating cutting tool configured to rotate around an axis of rotation in a rotary direction, and a support pad for such a tool is disclosed. The support pad defines a central longitudinal axis and has a first longitudinal edge side, an opposite second longitudinal edge side, a first transversal edge side and an opposite second transversal edge side. The support pad includes a first support surface, which is convexly curved as viewed in a plane perpendicular to the central longitudinal axis and a first recess, which extends into the first support surface in a direction from the first longitudinal edge side towards the second longitudinal edge side. The first recess extends to a final position on the first support surface.

A drilling head for a tubular shank having an inside diameter and threads may comprise an axial body comprising a duct exiting through a first end; threads adjacent the first end corresponding to the threads on the shank and aligning the duct with the shank inside diameter; a bore from an outer surface of the body to the duct; and two axially extending approximately parallel and offset surfaces adjacent a second end; and an insert affixed between the offset surfaces, the insert comprising: a first face at least partially contacting one offset surface and a second face at least partially contacting the other offset surface; one or more cutting edges adjacent the first face, the second face, or both; and a cutting lip adjacent one or more cutting edges.