3/8" THUNDERBOLT® Titanium Drill Bit

The Milwaukee 48-89-2218 is a 21/64" Thunderbolt® titanium-coated drill bit designed for general-purpose drilling in metal, wood, and PVC, built for durability and long service life.

Key Features

• Titanium Coating (TiN) – Helps reduce heat buildup and extends bit life up to 3× longer than standard bits
• 135° Split Point Tip – Starts on contact and helps prevent walking for accurate drilling
• Thicker Core (Thunderbolt Web) – Adds strength and reduces breakage under side load
• Parabolic Flute Design – Clears chips quickly for faster, cooler drilling
• 3-Flat Shank – Helps prevent slipping in the drill chuck

Specs (typical)

• Size: 21/64 in
• Material: High-speed steel with titanium coating
• Use: Metal, wood, plastic, PVC
• Type: Jobber-length drill bit

Best Uses

• Drilling holes in steel and sheet metal
• Wood framing and construction
• PVC/plastic fabrication
• General jobsite or maintenance drilling

Bottom Line

This is a single replacement drill bit, not a set. It’s meant for when you specifically need a durable 21/64" size bit that holds up better and drills cleaner than basic black oxide bits.