This Irwin cobalt drill bit cuts a 1/2" hole but is ground to a 3/8" reduced shank, so it fits a standard 3/8" drill chuck instead of requiring a 1/2" chuck. The 8 percent cobalt high-speed steel resists the heat and abrasion that ruin ordinary bits in tough metal, and the 135-degree split point starts drilling immediately with less force instead of walking across the work surface.

• 8 percent cobalt alloy high-speed steel for heat and abrasion resistance
• 135-degree split point starts on contact and minimizes bit walk
• Heavy-duty web construction for added strength and durability
• 3/8" reduced straight shank fits standard 3/8" chucks
• For tough metal drilling, including heavy-duty abrasive alloy metal and hardened steel
• Jobber length
• Size: 1/2" diameter x 6" overall length
• Irwin catalog number 3016032, one bit per card

Tip: Drill hard metals at low speed with cutting oil and steady, moderate pressure. Too much speed is what burns a cobalt bit; too much pressure is what breaks it.