Chip discharge during high-feed machining and low-feed machining particularly in a high-depth-of-cut state or the like is improved so as to provide adaptability to a wide range of cutting conditions during low depth and high depth cutting and during low-feed and high-feed machining and allow so-called freedom of feed during cutting to be improved. A cutting insert includes a cutting edge body and a substrate to which the cutting edge body is joined. The cutting edge body has a prismatic shape having a longitudinal direction and a lateral direction perpendicular to the longitudinal direction and includes a cutting edge formed on an intersecting edge between a peripheral side surface and an upper surface of the cutting edge body having the prismatic shape and a recessed part formed at a position on the upper surface of the cutting edge body which is more distant from the intersecting edge than from the cutting edge. The substrate has a projected part upwardly projecting from the upper surface of the cutting edge body.

A hole-saw, including a sidewall and an endcap, is provided. The endcap includes projections that fit within notches of the sidewall to form a brazed or welded joint that couples the endcap to the cylindrical sidewall. The projections extend through the notches and are brazed or welded to the base of the sidewall. The endcap couples to the sidewall to form a cylindrical hole saw body. The endcap rotates and supports the hole-saw during operation.

The present invention provides a cutting tool which comprises a cutting tool insert with a tip portion of cBN material having a cutting edge formed therein and a base portion forming a sintered composition with the tip portion, and a body portion coupling the cutting tool insert with a shank of the cutting tool, wherein the cutting tool insert has a rake face and a first flank face defining the cutting edge. The rake face has a negative rake angle relative to an axis parallel to a center axis of the body portion. A second flank face defining a further edge with the first flank face is formed such that the cutting edge and the further edge do not have a common vertex. The second flank face is tilted with respect to an axis parallel to a center axis of the body portion by an angle greater than 0.

The strength of the bond formed by a braze material between a polycrystalline hard material and a hard composite may be physically strengthened. For example, a method of physical strengthening may include etching a bonding surface of a polycrystalline material body to produce a synthetic topography on the bonding surface of the polycrystalline material body, the bonding surface opposing a contact surface of the polycrystalline material body; and brazing the bonding surface of the polycrystalline material body having the synthetic topography to a bonding surface of a hard composite using a braze material.

Object: To provide a cBN sintered compact having high wear resistance, and a cutting tool having high wear resistance that uses the cBN sintered compact.

Solution: A cBN sintered compact (1) including 50 vol. % or greater of cBN particles (2); and a binder phase (4) including Co; wherein in the binder phase (4), intra-phase particles (8) including Co.sub.aW.sub.b (where 0a0.95 and 0.05b1) are present. Additionally, a cutting insert (20) or similar cutting tool either includes a cBN tip (25) made from the cBN sintered compact (1) or is entirely made from the cBN sintered compact (1). The cBN sintered compact (1) and the cutting insert (20) or similar cutting tool have increased wear resistance.

A tool blank (30) for a cutting tool (1), such as an end mill, drill or engraving tool, includes a tool shank (2) configured to be received in a rotating tool holder of a processing machine, and a cutting head blank (3) fixedly connected to the tool shank (2). The cutting head blank (3) includes multiple cutting head blank elements (5) fixedly connected to each other, preferably soldered to each other, and made of a high hardness material such as polycrystalline diamond. A cutting tool (1), such as an end mill, drill or engraving tool, has at least one tool cutting edge (15) that is defined on such a tool blank (30) and extends over multiple cutting head blank elements (5) that are fixedly connected to one another.

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.

The present invention provides a cutting tool which comprises a cutting tool insert with a tip portion of cBN material having a cutting edge formed therein and a base portion forming a sintered composition with the tip portion, and a body portion coupling the cutting tool insert with a shank of the cutting tool, wherein the cutting tool insert has a rake face and a first flank face defining the cutting edge. The rake face has a negative rake angle relative to an axis parallel to a centre axis of the body portion. A second flank face defining a further edge with the first flank face is formed such that the cutting edge and the further edge do not have a common vertex. The second flank face is tilted with respect to an axis parallel to a centre axis of the body portion by an angle greater than 0.

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 rotary cutting tool with an elongate body disposed about a longitudinal axis, the elongate body including a helical flute and a polycrystalline-diamond cutting tip. The cutting tip comprises an inner portion having an inner point angle and an outer portion having an outer point angle different from the inner point angle.