... 4"46, 6, 7, 11, 12 —MAXDRILL Tapered Chisel BitTapered Chisel Bit is generally matched with the light-duty rock drill ... , to drill the rock hole within diameter of 50mm. It ... is widely used in metallurgy mine, geological exploration, water conservancy construction, electricity, traffic, tunnel, quarry stone project etc(1) Type: chisel ...