Drilling in alloyed and non alloyed steel up to tensile strength of 900nmu cast steel cast iron sintered iron die cast iron non iron metals aluminum hard plastic key features pack of 10self centering the drill bit has a particular tough core thickness and distinct hardness within its area of application thus ensuring long life specifications1 x 12 x 34 mm technical specifications diameter d mm 1 working length l1 mm 12 total length l2 mm 34