Abstract: A method of producing a plurality of discrete ultra-hard abrasive particles includes the steps of providing a plurality of granules, each comprising at least one ultra-hard abrasive particle, a precursor for the abrasive particle and a solvent/catalyst for the abrasive particle or precursor of such a solvent/catalyst, placing the granules with a separating medium between adjacent granules in the reaction zone of a high pressure/high temperature apparatus, subjecting the contents of the reaction zone to elevated temperature and pressure conditions at which the ultra-hard abrasive particle is crystallographically stable, recovering thus treated material from the reaction zone and removing the separating medium in the treated material to produce a plurality of discrete abrasive particles.

Abstract: A method is provided for producing a plurality of polycrystalline ultra-hard abrasive grit. The method includes the steps of providing a mass of ultra-hard abrasive particles or a mass of a combination of a precursor for such particles and a suitable solvent/catalyst, forming the mass into a plurality of green state granules, placing the granules with a separating medium between adjacent granules in the reaction zone of a high pressure/high temperature apparatus, subjecting the contents of the reaction zone to elevated temperature and pressure conditions which the ultra-hard abrasive particle is crystallographically stable, recovering the thus sintered material from the reaction zone and removing the separating medium in the sintered material to produce a plurality of crystalline abrasive grit. The ultra-hard abrasive is generally diamond or cubic boron nitride.

Abstract: A method is provided for producing a cutting tool such as a twist drill, end mill or the like. The method includes the steps of providing an unbonded assembly comprising a cylindrical core (10) having ends (12, 14) and an elongate side surface (16) covered partially or completely by a coherent, unsintered layer (18) comprising ultra-hard abrasive particles for producing an ultra-hard material, subjecting the unbonded assembly to elevated temperature and pressure conditions at which the ultra-hard abrasive is crystallographically stable, recovering the sintered product which comprises a cylindrical core (10) and a layer of ultra-hard abrasive material bonded to the core and working the sintered product to produce one or more cutting edges in the layer of ultra-hard abrasive material.

Abstract: A method of producing a plurality of discrete ultra-hard abrasive particles includes the steps of providing a plurality of granules, each comprising at least one ultra-hard abrasive particle, a precursor for the abrasive particle and a solvent/catalyst for the abrasive particle or precursor of such a solvent/catalyst, placing the granules with a separating medium between adjacent granules in the reaction zone of a high pressure/high temperature apparatus, subjecting the contents of the reaction zone to elevated temperature and pressure conditions at which the ultra-hard abrasive particle is crystallographically stable, recovering thus treated material from the reaction zone and removing the separating medium in the treated material to produce a plurality of discrete abrasive particles.

Abstract: A method is provided for producing a plurality of polycrystalline ultra-hard abrasive grit. The method includes the steps of providing a mass of ultra-hard abrasive particles or a mass of a combination of a precursor for such particles and a suitable solvent/catalyst, forming the mass into a plurality of green state granules, placing the granules with a separating medium between adjacent granules in the reaction zone of a high pressure/high temperature apparatus, subjecting the contents of the reaction zone to elevated temperature and pressure conditions which the ultra-hard abrasive particle is crystallographically stable, recovering the thus sintered material from the reaction zone and removing the separating medium in the sintered material to produce a plurality of crystalline abrasive grit. The ultra-hard abrasive is generally diamond or cubic boron nitride.

Abstract: A drill blank, particularly a blank for a micro-drill, comprises an elongate cylindrical cemented carbide body, having flat end surfaces, a recess formed in one end surface and taking the form of an island in that surface wholly surrounded by cemented carbide, and an abrasive compact located in the recess, bonded to a cemented carbide, and presenting a surface coincident with the carbide end surface in which the recess is located. A drill may be formed from the drill blank by suitably shaping the cemented carbide body, for example, by fluting, in the region of the abrasive compact to expose the abrasive compact.

Abstract: The invention provides a method of manufacturing an abrasive body which includes the steps of providing a mixture comprising a mass of nanosized ceramic particles and a mass of ultra-hard abrasive particles, typically diamond and cubic boron nitride, and sintering the mixture into a coherent body. The sintering conditions used are hot-pressing conditions.