Milwaukee 21/64" THUNDERBOLT® Black Oxide Drill Bit (6 PK)

REINFORCED WEB GEOMETRY FOR SUPERIOR SIDE-LOAD RESISTANCE

In high-torque drilling applications, standard bits often fail at the core when subjected to lateral pressure or uneven feed rates. The Milwaukee Thunderbolt series addresses this mechanical vulnerability with a significantly thicker web, providing the structural rigidity required for heavy-duty metal, wood, and plastic boring. This 21/64" bit utilizes a parabolic flute design that doesn't just clear chips—it evacuates them at a rate that keeps the cutting edge cool, preserving the temper of the high-speed steel and extending the professional's ROI. The 3-flat Secure-Grip shank is a critical design feature, ensuring that the drill's torque is fully realized at the tip rather than slipping in the chuck under heavy load.

• / Thunderbolt Web: Reinforced core design provides maximum durability and protects against breakage from side-load forces during handheld operation.
• / 135° Split Point: Precision-ground tip starts on contact, eliminating bit walk and the need for a center punch on curved or hard surfaces.
• / Parabolic Flute: High-efficiency geometry clears chips and debris rapidly to minimize heat buildup and maintain cutting speed.
• / 3-Flat Secure-Grip™ Shank: Machined flats prevent the bit from spinning in the drill chuck, ensuring consistent power transfer in high-torque scenarios.
• / Black Oxide Coating: Provides essential lubricity and corrosion resistance, reducing friction and extending bit life in demanding environments.

WHAT'S IN THE BOX

(6) 21/64" Thunderbolt® Black Oxide Drill Bits (48-89-2837)