... .8, 6, 7, 11, 12 3.Water Hole: 2 Taper Rock Bits We are a manufacturer specializes in producing kinds ... taper chisel bits, cross bits, button bits, tapered drill rods, integral drill steels, plug hole integral steels, pick rods, thread cross bits, thread ... following types according to clients' need taper:4.8,6,7,11,12The diameter for taper:15,19,22,24,25(mm ...