Hertel C.E05.0531 Aircraft Extension Drill Bit Size 4

Product Description

The HERTEL C.E05.0531 is a wire gauge size 4 aircraft extension drill bit designed for deep-reach drilling applications where a standard-length bit cannot access the work area. Built from high-speed steel with an oxide finish, this bit features a 135-degree split point that is self-centering and eliminates the need for a center punch on most materials. The tapered web-thinned construction reduces cutting resistance and improves chip evacuation. At 12 inches overall length with a 2.5-inch spiral flute, it is the right tool for reaching into confined spaces in aerospace, automotive, and structural fabrication work. Meets NAS 907 standards.

This bit is suited for general-purpose drilling in metal, aluminum, and composite materials where extended reach is required. Typical applications include drilling through airframe structures, deep cavities in machinery, and stacked materials that exceed the reach of conventional jobber-length bits. The straight cylindrical shank accepts standard drill chucks without adapters. Right-hand cutting direction is standard for use with conventional corded or cordless drills and drill presses. The 0.2090-inch decimal diameter corresponds to wire gauge size 4.

Key Features

• 135-degree split point is self-centering and reduces walking on entry
• 12-inch overall length provides extended reach into deep or confined spaces
• High-speed steel construction handles a broad range of metals and composites
• Oxide finish provides light corrosion resistance and reduces friction during cutting
• Tapered web with web thinning lowers thrust force and improves chip flow
• Meets NAS 907 standard for aircraft-quality drill bits
• 2-flute spiral design with 2.5-inch flute length clears chips efficiently

Compatibility

Designed as a general-purpose aircraft extension drill bit in wire gauge size 4 (0.2090 inches) with a straight cylindrical shank; fits any standard drill chuck sized for a 0.2090-inch shank diameter.

Installation Notes

This bit is typically installed and used by machinists, aerospace technicians, and metalworking tradespeople. Secure the straight shank firmly in a keyed or keyless chuck before operation and verify the bit runs true before engaging the workpiece. Use appropriate cutting fluid for ferrous metals to extend tool life and maintain hole quality. Wear ANSI-rated eye protection and secure the workpiece to prevent rotation during drilling.