| 摘要 |
A method of producing a composite cutting insert for a twist drill includes the steps of cutting an intermediate blank (16) from a composite diamond compact (10). The intermediate blank comprises a relatively broad tungsten carbide strip (20) with a relatively narrow polycrystalline diamond strip (18) at one edge. First and second cutting insert halves (22.1, 22.2) are cut from the intermediate blank, each cutting insert half defining a cutting edge (26, 28) of the diamond material. The cutting insert halves are arranged back-to-back to form a composite cutting insert (24), with the cutting edges on opposite sides of a central plane (A-A). The cutting edges are arranged to define a chevron shaped composite cutting edge. The cutting insert halves are preferably brazed together to form a unitary cutting insert. The invention extends to a method of producing a twist drill including the steps of forming a slot-shaped seat (30) diametrally in the end of a twist drill body, and brazing the composite cutting insert into the seat. <IMAGE> |
