1.Diamond bits 2.coal mining,many types 3.good price and high quality 4. ISO9001 5. Export to many countries ... tools and excavating coal pick cutter tools.1. Integral drill steels (Integral Drill Rods)Shank H22x108mm, H19x108mm, standard hex, Bit diameters include ... 20-42mm.2. Tapered drilling tools (Tapered Drill Steel)Including:Drill rods with Shank H22x108mm,(6,7,11,12 degree ...