TUNGSTEN GRIT EDGED HOLE SAW This hole saw will cut ceramics, fiberglass, hardwood, cast iron,composites, glass resins, asbestos and other abrasive materials that would wear out conventional saws. They have tough steel body with multiple carbide grits permanently bonded to the teeth. Very efficient at high speed. They prevent binding action and cut smooth holes in the materials up to 38mm or 44mm ...