Milwaukee® Thunderbolt® pilot bits are designed for extreme durability and long life. The Thunderbolt® web features a thicker core than a standard pilot bit, which provides ultimate strength and protects against side-load breakage. A specially designed parabolic flute form clears chips and debris fast to keep the bit cool. A precision ground 135° split point starts on contact to prevent walking for fast, accurate holes. Great for drilling on curved surfaces, requires less effort to drill, and is highly recommended for use with portable drills.