Abstract: Glass bonded grinding wheels including graphite or other inert dry film lubricant filler can be made by conventional techniques if the filler material is protected from oxidation by a metal cladding. Diamond or cubic boron nitride wheels are particularly described and high grinding ratios are achieved. Low porosity can be achieved because of the wettability of the metal cladding by the glass during firing.

Abstract: Ceramic bonded grinding and honing tools employing diamond or cubic boron nitride abrasive particles are improved by the inclusion of from 10 to 53%, by volume, of graphite in the bond, based on the total bond solids, including graphite. The bond must have a porosity volume less than 15% for honing applications and less than 10% for grinding wheels, preferably the graphite should be finely particulate. Applications in dry grinding and honing of hard materials are described. For dry grinding the optimum graphite content of the bond is from 34 to 45 volume percent. The bond may include crystalline filler such as alumina, zirconia, silicon carbide, or crystalline filler formed in situ by devitrification; and the abrasive particles may be metal coated. MoS.sub.2 or hexagonal boron nitride may substitute for all or part of the graphite and metal powders may be employed to replace up to 50% by volume of the graphite or graphite substitute materials.