... Drill rods with Shank H22x108mm,(6,7,11,12 degree taper) taper rods in most lengths.button bits, cross type ... and chisel bits with(6,7,11,12 degree taper).Bit diameter:28mm-57mm.3.Extension drilling toolsButton ... a middle stop to prevent walking along the thread. Include couplings sleeve(threaded R22,R25,R28,R32 ... 4mm,25mm,30mm,33mm,38mm,etc.8.Blast furnace tap hole drill tools.(Rod, Cross type bits, ...