... 800mm 3.Diameter: 17mm - 22mm 4.Hex: 19mm, 22mm Plug Hole Drill Rod We are a manufacturer specializes in producing kinds of ... chisel bits, cross bits, button bits, tapered drill rods, integral drill steels, plug hole integral steels, pick rods, thread cross bits, ... working conditions. The plug hole integral drill rod is widely used in stone pit field to drill small holes. Because of the integration ...