Drill Bit, Cobalt, Left Hand, 135 Degree Split Point, Mechanics Length, 15/32", Bulk IRWIN offers a complete line of Metal Twist Drill Bits, including Black Oxide, Turbo Point, Titanium Nitride, and Cobalt Drill Bits.. Perfect for use with screw extractors. Constructed of M-42 8 percent cobalt high speed steel for super abrasive resistance in tough metals. Heavy duty spiral flute design produces faster chip ejection. Shorter cutting lips reduce torque for drilling in high tensile strength materials.. 135-degree split point reduces feed pressure for easier penetration without work hardening. Ideal for use with screw extractors.