Hertel C.E03.0366 Aircraft Extension Drill Bit No. 27

Product Description

The HERTEL C.E03.0366 is a No. 27 aircraft extension drill bit engineered 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 reduces the need for a center punch on most materials. The 2-flute spiral configuration with a tapered, web-thinned construction promotes efficient chip evacuation and reduces thrust during drilling. With a 6-inch overall length and 1.875-inch flute length, it provides the extended reach common in aircraft and sheet-metal structural work. Weight is 0.3 pounds.

This bit is suited for general-purpose drilling in metal fabrication, aerospace maintenance, and structural assembly where extended reach into confined or recessed areas is required. The No. 27 wire gauge size (0.1440-inch decimal diameter) is a common sizing for pilot holes and fastener clearance holes in light-gauge steel, aluminum, and similar materials. Installation is performed by licensed machinists, aircraft mechanics, or experienced metalworking tradespeople. It meets NAS 907 standards, making it appropriate for aerospace and high-specification industrial drilling operations.

Key Features

• No. 27 wire gauge size — 0.1440 inch decimal diameter — for precise pilot and clearance hole drilling
• 135-degree split point is self-centering and reduces walking on hard or flat surfaces
• 6-inch overall length provides extended reach into confined or deep work areas
• High-speed steel construction with oxide finish for general-purpose metal drilling
• Web-thinned, tapered web configuration reduces cutting thrust and improves chip flow
• Meets NAS 907 standard for aerospace and high-specification applications

Compatibility

Designed as a general-purpose aircraft extension drill bit for use with standard straight-shank drill chucks in hand drills, drill presses, and right-angle drill motors commonly used in aerospace and metal fabrication work.

Installation Notes

This bit is installed and used by machinists, aircraft mechanics, and metalworking tradespeople following applicable shop safety and aerospace maintenance procedures. Secure the straight cylindrical shank firmly in a properly sized drill chuck before operation. Use appropriate cutting fluid or lubricant when drilling ferrous metals to extend tool life and maintain hole quality. Inspect the cutting edges before each use and do not use the bit if chipped, cracked, or dull.