... 3.Bit size:56-153mm Civil engineering tools PDC drill bit Steel body PDC drill bit is made from PDC cutter ... blast hole, dam and roadway construction etc.PDC concave drill bitProduct Code:NW-3Standard Size: 56,65,75,94, ... 113,133,153mmWings:3WPDC concave drill bitProduct Code:NW-4Standard Size: 65,75, 94,113 ... as per clients'drawings/samples/requirements Civil engineering tools PDC drill bit