Precision Twist Drill 6001345 Letter X Aircraft Drill Bit

Product Description

The PRECISION TWIST DRILL 6001345 is a Letter X aircraft extension drill bit designed for deep-hole drilling applications in metal fabrication, aerospace, and structural work. Built from high speed steel with an oxide finish, it features a 135-degree split point that is self-centering and web-thinned for reduced thrust and cleaner entry without a center punch. The straight-cylindrical shank measures 0.397 inches in diameter, matching the drill diameter, and the 3.75-inch flute length provides the reach required for extended-depth drilling in sheet metal, structural members, and assemblies where a standard-length bit falls short. This is a right-hand cutting, two-flute spiral drill with a tapered web configuration rated for general-purpose performance.

This drill bit is suited for use in residential and commercial metal fabrication, aircraft and aerospace maintenance, HVAC equipment assembly, and structural drilling applications where access depth exceeds the capacity of a jobber-length bit. The Series 502-6 designation places it within a recognized line of aircraft extension drills built to NAS 907 Type B standards, making it appropriate for use on aluminum, mild steel, and similar materials where consistent hole sizing to Letter X (0.397 inches decimal equivalent) is required. Licensed tradespeople including sheet metal mechanics, HVAC technicians, and structural fabricators regularly reach for extension drills in this size range.

Key Features

• 135-degree split point is self-centering and reduces walking on entry without a pilot hole
• Web-thinned, tapered web construction lowers cutting resistance and improves chip clearance
• High speed steel construction provides durability across aluminum, mild steel, and similar materials
• Oxide finish improves lubricity and provides basic corrosion resistance during storage
• 3.75-inch flute length delivers extended reach for deep-hole and aircraft-style drilling applications
• Meets NAS 907 Type B standards for aircraft extension drill geometry

Compatibility

Designed as an OEM-style general-purpose aircraft extension drill bit compatible with standard straight-shank drill chucks accepting a 0.397-inch diameter shank across corded drills, drill presses, and pneumatic drill motors used in metal fabrication and maintenance applications.

Installation Notes

Installation of this drill bit requires a chuck rated for the 0.397-inch straight-cylindrical shank diameter. Secure the shank fully into the chuck jaws before operation and verify the bit runs true to minimize deflection during deep-hole drilling. Use appropriate cutting fluid or lubricant when drilling steel to extend bit life and maintain hole quality. Power down the drill and allow the bit to cool before changing or handling after extended use.