... a professional productions base of series of rock drilling tools, mining tools, DTH Drill tools. Construction tools and excavating coal pick ... abroad to come for business talks.About products1. Integral drill steels (Integral Drill Rods)Shank H22x108mm, H19x108mm, standard hex. Bit ... diameters include 20-42mm.2. Tapered drilling tools (Tapered Drill Steel)Including:Shank H22x 108mm, (6, 7, 11, 12 ...