S&D Black Gold cobalt drill bits are designed for extreme durability and long life. A specially designed parabolic flute form clears chips fast, while the straight shank fits most drill chucks. The 135 degree split point tip delivers a precision start and prevents walking for fast, accurate holes. Effective for drilling on curved surfaces, Black gold bits require less effort to drill through stainless metal, wood and PVC, and are highly recommended for use with portable drills. Features: Fast, accurate drilling: 135 degree split point tip starts on contact to prevent walking, while the parabolic flute clears chips fast. Reduced slipping: straight shank fits most drill chucks. Corrosion resistant: Black gold fully ground finish provides lubricity and resists corrosion of the bit. Versatile: Reduced shank diameter for use in 1/2 in. Specifications: Shank: 1/2 in. Reduced Pack: Qty 8 Type: Twist Drill Bits Coating: Black Gold Length: 6 in. Flute Length: 3 in. Size: 9/16″, 5/8″, 11/16″, 3/4″, 13/16″, 7/8″, 15/16″, 1″ in. Black and gold polished treatment adds lubricity and creates small pockets on the surface of the tool that act to hold coolant near the cutting edge. 135-Degree split point for accurate centering and fast penetration and round shanks allow use with a wide variety of toolholding systems. When run in a counterclockwise direction (right-hand cut) spiral fluted tools evacuate chips up and out of the cut to reduce clogging. Ideal for drilling in cast iron, zinc alloy, copper, stainless steel and so on.