1.coal mining tools 2.ore mining, many type 3.good price,high ... hex. Bit diameters include 20-42mm.2. Tapered drilling tools (Tapered Drill Steel)Including:Shank H22x 108mm, (6, ... Flat face, Drop centre, Normal and Retrac body.Tungsten carbide (Buttons): Spherical, Ballistic and Conical. (Threaded R32, R38 ... 33mm, 38mm, etc.8. Blast furnace tap hole drill tools. (Rod, Cross bits, button bits and X-type ...