Taper Rock DrillingTools 1.Diameter: 30mm - 46mm 2.Taper: 4.8, 6, 7, 11 ... in producing kinds of rock drilling tools includes taper chisel bits, cross bits, button bits, tapered drill rods, integral drill steels, plug ... -duty rock drill, to drill the rock hole within diameter of 50mm. The drill tools are used in metallurgy ... clients' need taper:4.8,6,7,11,12The diameter for taper:15,19,22,24,25(mm) Drill ...