... quality of best quality alloy steel bar and tungsten carbides, through heat treatment. —MAXDRILL Tap hole Drill RodIt was widely used in big steel mill ... , SAE1020, AISI1020, ASTM A106B, ASTM A53B, ST45, ST42.(2)Out diameter: hex.19mm, hex.22mm ,hex.28mm , hex.32mm, dia.32mm ... .—MAXDRILL Tap hole Drill Bit(1)Diameter:38mm-70mm.(2) shape:carbide 3-blade type , steel cross bit , carbide cross bit ,button ...