Forming of cutting edges by the controlled graphitization of diamond

In a method for forming convex facet surfaces on opposed surfaces terminating at an edge of a cutting instrument, said opposed surfaces comprising diamond, diamond-like carbon or a mixture thereof, the improvement comprising the step of contacting said opposed surfaces with juxtaposed rotating wheels having smooth contact surfaces coated with diamond, diamond-like carbon or a mixture thereof, each wheel having an axial length defining an entry and an exit end, said wheels being arranged and adapted to concurrently contact said opposed surfaces at progressively changing angles of contact as said opposed surfaces are moved from said entry end to said exit end to thereby form a facet on each of said opposed surfaces, the rotational velocity of said wheels and the contact pressure of said wheels against said opposed surfaces being sufficient to remove a portion of said opposed surfaces by a process of graphitization.

In a method for sharpening a steel razor blade, the cutting edge of which has been coated with a hard layer of diamond, diamond-like carbon or a mixture thereof, the improvement comprising contacting said cutting edge with a rotating wheel bearing a smooth coating of diamond, diamond-like carbon or a mixture thereof, the rotational velocity of said wheel and the contact pressure of said wheel against said cutting edge being sufficient to remove a portion of said hard layer by a process of graphitization.