Hertel C.E03.0531 Aircraft Extension Drill Bit No.4 Hss

Product Description

The HERTEL C.E03.0531 is a No. 4 wire size aircraft extension drill bit designed for deep-reach drilling applications in metal fabrication, aerospace maintenance, and general industrial work. Manufactured from high-speed steel (HSS) with an oxide finish, this bit features a 135-degree split point that self-centers on contact, reducing walking and the need for a center punch. The 6-inch overall length provides the reach required to access recessed or obstructed bore locations that standard-length bits cannot reach. With two right-hand spiral flutes and a web-thinned, tapered web configuration, the bit clears chips efficiently and reduces thrust during drilling.

This aircraft extension drill bit is suited for use in aviation maintenance, sheet metal work, structural fabrication, and other trades where extended reach into tight or layered assemblies is required. The straight cylindrical shank seats securely in standard drill chucks or right-angle drill attachments commonly used in aircraft and structural applications. Its general-purpose performance rating and compliance with NAS 907 make it appropriate for a range of ferrous and non-ferrous materials encountered in the field.

Key Features

• No. 4 wire size, 0.2090-inch decimal diameter for precise, spec-driven hole sizing
• 135-degree split point with self-centering geometry reduces walk-off and eliminates center-punching on most materials
• Web-thinned tapered web lowers cutting resistance and reduces required thrust force
• 6-inch overall length provides extended reach into recessed and obstructed locations
• 2.5-inch spiral flute length promotes efficient chip evacuation during deep drilling
• High-speed steel construction with oxide finish for heat resistance in general-purpose drilling
• Meets NAS 907 standard for aircraft-industry drill bit performance

Compatibility

Designed as a general-purpose aircraft extension drill bit compatible with standard drill chucks accepting a 0.2090-inch straight cylindrical shank, suitable for use with portable drills, right-angle drills, and drill presses in aviation maintenance and industrial fabrication environments.

Installation Notes

Installation should be performed by qualified machinists, aviation maintenance technicians, or experienced fabricators familiar with hand and machine drilling procedures. Secure the workpiece fully before drilling to prevent movement, and ensure the shank is fully seated and tightened in the chuck before operation. Use appropriate cutting fluid for the material being drilled to extend bit life and maintain hole quality. Inspect the cutting edges and web area before each use and remove from service if chipping or excessive wear is observed.