Hertel C.E03.0253 Aircraft Drill Bit No 39 Hss

Product Description

The HERTEL C.E03.0253 is a No. 39 wire-gauge aircraft extension drill bit engineered for deep-reach drilling in sheet metal, airframe structures, and tight-clearance assemblies. Built from high-speed steel with an oxide finish, it features a 135-degree split point that is self-centering and reduces the need for a center punch. The tapered web and web-thinned geometry lower cutting resistance and improve chip evacuation. At 6 inches overall length with a 1.375-inch spiral flute, it gives technicians the reach required for stacked-material and hard-to-access drilling without sacrificing rigidity. This bit meets NAS 907 standards and is suited for general-purpose production and maintenance work.

This drill bit is used where standard-length bits cannot reach — structural panel assemblies, fuselage repairs, HVAC sheet metal ductwork, and deep-counterbore setups in light fabrication. The straight cylindrical shank seats directly in standard drill chucks and pneumatic drill motors commonly used in aviation maintenance, sheet metal shops, and industrial assembly environments. Right-hand cutting direction is compatible with all standard rotary drilling equipment. The 0.0995-inch decimal diameter corresponds to No. 39 wire gauge, making it a direct fit for close-tolerance hole sizing in thin-gauge materials.

Key Features

• 135-degree split point is self-centering and reduces walking on hard or curved surfaces
• Web-thinned tapered web lowers thrust requirements and improves chip flow
• 6-inch overall length provides extended reach for deep or obstructed drilling locations
• High-speed steel construction with oxide finish for corrosion resistance and reduced friction
• Spiral flute with right-hand cut clears chips efficiently in sheet metal and stacked materials
• Meets NAS 907 standard for aircraft extension drill bits

Compatibility

Designed as a general-purpose aircraft extension drill bit compatible with standard straight-shank drill chucks and pneumatic drill motors used in aviation maintenance, sheet metal fabrication, and industrial assembly applications.

Installation Notes

Installation and use of this bit should be performed by qualified machinists, aviation maintenance technicians, or experienced tradespeople familiar with drilling procedures for the specific material being worked. Secure the workpiece firmly before drilling and confirm the chuck is fully tightened on the straight cylindrical shank before operation. Use appropriate cutting fluid for harder alloys to extend bit life and maintain hole quality. Inspect the cutting edges before each use and replace the bit if chipping, dullness, or deformation is observed.