Milwaukee Thunderbolt cobalt drill bits are designed for extreme durability and long life in specialty applications. The Thunderbolt web features a thicker core than a standard drill bit to provide ultimate strength and protect against side-load breakage. A specially designed parabolic flute form clears chips and debris fast to keep the bit cool. The 135 degree split point tip delivers a precision start and prevents walking for fast, accurate holes. Effective for drilling on curved surfaces, Milwaukee Thunderbolt cobalt bits require less effort to drill through stainless steel, high alloy steel and cast iron and are highly recommended for use with portable drills. RED HELIX™ - designed for rapid chip removal135 degree split point for precision start no walkingChip breaker to reduce heat build-upFast, accurate drilling - 135° split point tip starts on contact to prevent walking, while the parabolic flute clears chips fastCobalt steel 10x life versus black oxideDesigned with a Variable Helix ™ that includes an aggressive 35° Helix Angle which ends at 15° providing rapid chip removalCorrosion resistant - cobalt coating keeps the bit sharp and provides added protection from heat build-up1/8 in. diameterUp to 10x life vs. black oxideRed Helix design for rapid chip removal