A cylindrical calibration head for the drilling of a shaft, includes three flutes arranged evenly around the circumference so that they are spaced one from the next by an angle of 120° with respect to a rotation with respect to the axis of the calibration head, the flutes allowing for the removal of chips and the passage of lubricant during drilling, each of the flutes including a machining insert of which the position in the flute can be adjusted using an adjusting cartridge.

A deep hole drilling system and methods provide stability and cutting performance to produce deep holes having desired straightness. The system may include a replaceable cutting head provided with a center cutting member and first and second side cutting inserts. The tool provides a major diameter with the OD cutting margins on the replaceable side inserts, as well as possibly cutting margins on the center cutting member. Adjustment mechanisms are provided to adjust the center cutting member and/side cutting inserts.

An insert includes four identical cutting edges disposed at the intersection of top and side surfaces surface. Each cutting edge includes a first part edge disposed tangent to a first reference circle aligned about the central mounting aperture; a second part edge extending from the first part edge, the second part edge being connected to the first part edge via a convex curved portion; a third part edge disposed tangent to a second reference circle aligned about the central mounting aperture, the second reference circle having a smaller diameter than the first reference circle, the third part edge being connected to the second part edge via a concave curved portion; and a convexly curved corner portion extending from the third part edge of one of the identical cutting edges to the first part edge of another one of the identical cutting edges.

A drill reamer (20) comprises an elongate body (21) disposed about a longitudinal axis. The elongate body comprises flutes (22a-22d) having separate hard cutting sections (27a, 28a, 28a, 28b, 28b) and a soft cutting section (24a, 24b). The soft cutting section is formed of a material such as carbide having a hardness that is less than that of the hard cutting sections, which may be formed of polycrystalline diamond. At least one first hard cutting section (27a) is axially displaced relative to at least one second hard cutting section (28a, 28a). The reamer has a tip cutting edge (23a, 23c) and tapered cutting edge portions (24a-24d) disposed at an acute angle relative to the longitudinal axis.

A deep hole drilling system and methods provide stability and cutting performance to produce deep holes having desired straightness. The system may include a replaceable cutting head provided with a center cutting member and first and second side cutting inserts. The tool provides a major diameter with the OD cutting margins on the replaceable side inserts, as well as possibly cutting margins on the center cutting member. Adjustment mechanisms are provided to adjust the center cutting member and/side cutting inserts.

A cutting insert includes a top face, a bottom face and a plurality of side walls extending between the top face and the bottom face. A peripheral cutting edge is defined at the juncture of each side wall and the top face. Each cutting edge includes a linear cutting edge portion and a concave cutting edge portion that curves inwardly in a plane that is perpendicular to a plane containing a central axis of the cutting insert. A radiused corner portion connects two adjacent cutting edges. Each linear cutting edge portion extends from one radiused corner portion to the concave cutting edge portion and the concave cutting edge portion extends from the linear cutting edge portion to another radiused corner portion.

An insert includes four identical cutting edges disposed at the intersection of top and side surfaces surface. Each cutting edge includes a first part edge disposed tangent to a first reference circle aligned about the central mounting aperture; a second part edge extending from the first part edge, the second part edge being connected to the first part edge via a convex curved portion; a third part edge disposed tangent to a second reference circle aligned about the central mounting aperture, the second reference circle having a smaller diameter than the first reference circle, the third part edge being connected to the second part edge via a concave curved portion; and a convexly curved corner portion extending from the third part edge of one of the identical cutting edges to the first part edge of another one of the identical cutting edges.