IRWIN 63121 Jobber Drill Bit, Spiral Flute, 3-5/16 in L Flute, Cylinder

High speed steel with M-35; five percent cobalt; for higher heat and abrasion resistance; heavy duty web construction for strength and durability. Split point begins drilling immediately; minimizing bit walk when used in applications such as metal drilling, including heavy duty abrasive alloy metal drilling on hardened steel (heat-treated).