... ,12 degree taper) taper rods in most lengths.button bits, cross type bits and chisel bits with( ... degree taper).Bit diameter:28mm-57mm.3.Extension drilling toolsButton bit, face design :Flat face, drop centre, Normal and ... straightness.4.Down the hole hammers and DTH button bits(Down The Hole Drilling)Offer ir hammers, ... hole drill tools.(Rod, Cross type bits, button bits and X type bits etc) DTH ...