Winner - Tapered Drill Bit

Diameter：28mm to 70mm. Taper: 4° 46`, 6°, 7°, 11° and 12°. Skirt: short skirt and long skirt. Bit type: chisel bits, cross bits and spherical / ballistic / parabolic button bits. Quality aircraft alloy steel and tungsten carbide, optimum design, state of art manufacturing, multiple precise heat-treatment. Highest penetration rate, maximum wear resistance, longest lifespan and outstanding performance  in roughest working conditions.