Patents Assigned to De Beers Industrial Diamon Division Limited
  • Patent number: 5195403
    Abstract: A method of producing a composite cutting insert for a twist drill includes the steps of cutting an intermediate blank from a composite diamond compact. The intermediate blank comprises a relatively broad tungsten carbide strip with a relatively narrow polycrystalline diamond strip at one edge. First and second cutting insert halves are cut from the intermediate blank, each cutting insert half defining a cutting edge of the diamond material. The cutting insert halves are arranged back-to-back to form a composite cutting insert, with the cutting edges on opposite sides of a central plane. 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 diametrally in the end of a twist drill body, and brazing the composite cutting insert into the seat.
    Type: Grant
    Filed: February 28, 1992
    Date of Patent: March 23, 1993
    Assignee: De Beers Industrial Diamon Division Limited
    Inventors: Mohammad N. Sani, Graeme D. Dufferwiel