Cobalt Screw Machine Length Drills ? Heavy duty construction ? 135 self-centering point eliminates walking and reduces thrust ? Short length provides maximum rigidity for increased hole accuracy and extended tool life ? Cobalt steel offers increased hardness, toughness, wear resistance and heat resistance ? Recommended for drilling tough, high tensile strength materials and materials that generate higher cutting temperatures including high alloy steels, ferrous castings, titanium, inconel, stainless steels and other difficult-to-drill materials