Hertel C.E03.0391 Aircraft Extension Drill Bit No. 23

Product Description

The HERTEL C.E03.0391 is an aircraft extension drill bit designed for drilling in hard-to-reach locations where a standard-length bit cannot reach. Built from high-speed steel with an oxide finish, this bit measures 6 inches in overall length with a 2-inch spiral flute. The 135-degree split point is self-centering and web-thinned, reducing the need for a center punch and helping the bit walk less on entry. Wire gauge size No. 23 corresponds to a decimal diameter of 0.154 inches. A licensed HVAC technician, machinist, or aircraft maintenance professional would typically install or use this bit in light-duty to general-purpose drilling applications.

This bit is suited for use in sheet metal, aluminum, and similar materials encountered in aircraft maintenance, HVAC ductwork, and general fabrication work. The extended 6-inch overall length is engineered to access recessed surfaces, tight bays, and structural cavities where standard-length bits fall short. The straight cylindrical shank seats in standard drill chucks without adapters. Right-hand cutting direction is standard for conventional drill press or hand-drill use.

Key Features

• 135-degree split point reduces walking and improves self-centering on entry
• Web-thinned, tapered web configuration lowers thrust requirements during drilling
• High-speed steel construction handles general-purpose drilling in metal and similar substrates
• Oxide finish provides basic corrosion resistance and lubricity
• 6-inch overall length with 2-inch spiral flute for extended reach applications
• Straight cylindrical shank at 0.154 inches fits standard chucks directly
• Meets NAS 907 standards for aircraft extension drill bits

Compatibility

Designed as a general-purpose aircraft extension drill bit conforming to NAS 907, compatible with standard drill chucks accepting a 0.154-inch straight cylindrical shank.

Installation Notes

This bit is typically used by machinists, aircraft maintenance technicians, and fabricators with a hand drill or drill press. Secure the shank fully in the chuck before operation and verify the workpiece is clamped to prevent movement. Use appropriate cutting fluid on metal substrates to extend bit life and reduce heat buildup. Inspect the cutting edges for wear or chipping before each use and replace the bit if the point shows signs of damage.