Hertel C.E05.02375 Aircraft Extension Drill Bit No. 42

Product Description

The HERTEL C.E05.02375 is a No. 42 wire-gauge 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, it features a 135-degree split point with web thinning for self-centering entry and reduced thrust. The bit measures 12 inches in overall length with a 1.25-inch spiral flute and a straight cylindrical shank diameter of 0.0935 inches. It cuts right-hand with a two-flute, tapered-web configuration suited to general-purpose metal drilling. Licensed machinists, aircraft mechanics, and sheet metal technicians are the primary installers of this tool.

This extension drill bit is built for applications that require reach beyond standard bit lengths, including aircraft structural assembly, deep-cavity metalwork, and confined-space drilling in fabrication or maintenance environments. The No. 42 diameter (0.0935 inches) is commonly used for close-tolerance fastener hole preparation in aluminum, steel, and similar materials. The 135-degree split point geometry reduces walking and allows clean entry on curved or angled surfaces without a center punch in many setups. It meets NAS 907 standards, making it appropriate for aerospace and high-specification industrial applications.

Key Features

• No. 42 wire gauge size, 0.0935 inches decimal diameter
• 135-degree split point with web thinning for self-centering, reduced-thrust entry
• 12-inch overall length for deep-reach and extension drilling
• High-speed steel construction with oxide finish for wear resistance
• Two-flute right-hand spiral, tapered web configuration for chip clearance
• Meets NAS 907 standard for aerospace-grade drill bit performance

Compatibility

Designed as a general-purpose aircraft extension drill bit for use in hand drills, right-angle drill attachments, and drill presses accepting a straight cylindrical shank of 0.0935 inches. Suitable for aerospace, sheet metal, and industrial fabrication applications requiring NAS 907-compliant tooling.

Installation Notes

This bit is installed and used by aircraft mechanics, machinists, and sheet metal technicians. Secure the straight shank firmly in a compatible chuck before use and verify concentricity to prevent premature wear or bit breakage. Always wear appropriate eye protection and follow applicable shop safety and aviation maintenance standards when drilling in structural assemblies. Do not exceed the recommended feed rate or RPM for the workpiece material and bit diameter.