Drilling Rig, Drill Bits, DTH Drill Rig manufacturer / supplier in China, offering 17 1/2 Inch 6 Blades PDC Bit with Hard Facing on Body, High Performance 17 1/2 Inch 6 Blades Steel or Matrix Body PDC Drilling Bit, 17 1/2 Inch 6 Blades Steel or Matrix Body PDC Drill Bit for Hard Rock and so on.