Rock Drill Bit for Mining and Well Borehole, Rock Drill Rod for Tunneling and Open Mining, Tricone Roller Bit and PDC Drag Bit for Borewell manufacturer / supplier in China, offering Hex22/Hex25*108mm/159mm Shank Taper Drill Rod, Two Cutter Wings Tungsten Carbide Coal Mining Drill Bit, High Carbon Steel Friction Welding DTH Drill Pipes Drill Rods and so on.