Precision Twist Drill 6001367 Letter U Extension Drill

Product Description

The PRECISION TWIST DRILL 6001367 is a Letter U (0.368 inch diameter) aircraft extension drill bit built for deep-hole drilling applications where a standard-length bit cannot reach. Manufactured from high speed steel (HSS) with an oxide finish, it features a 135-degree split point that is self-centering and web-thinned, reducing walking and cutting entry force. The 12-inch overall length and 3.625-inch spiral flute are sized to the 4xD flute-to-diameter ratio common in aerospace and structural drilling per NAS 907 Type B. Licensed trades and production shops use this bit for metal fabrication, airframe work, and deep structural drilling.

This drill bit fits general-purpose metal drilling tasks where extension reach is required — typical scenarios include drilling through deep structural steel members, thick weldments, or confined access points that a jobber-length bit cannot service. The straight-cylindrical shank accepts standard drill chucks without an adapter. Right-hand cutting direction is standard for conventional drill press and hand-drill operation. Series 502-12 designates the 12-inch extension family within the Precision Twist Drill line.

Key Features

• Letter U size — 0.368 inch diameter for precise dimensional drilling
• 135-degree split point with web thinning reduces thrust and eliminates center-punching on most metals
• Self-centering tip geometry improves hole location accuracy
• 12-inch overall length provides extended reach into deep or restricted workpieces
• High speed steel construction handles steel, aluminum, and general ferrous and non-ferrous materials
• Oxide finish provides mild lubricity and corrosion resistance during storage and use
• Meets NAS 907 Type B standards for aircraft-application drill bits

Compatibility

Designed as a general-purpose aircraft extension drill bit compatible with any standard drill chuck accepting a 0.368-inch straight-cylindrical shank. Suitable for use in drill presses, magnetic drills, and hand drills capable of driving the 0.368-inch shank diameter.

Installation Notes

Installation of this drill bit is performed by machinists, aircraft maintenance technicians, fabricators, and general trades using standard drill chucks. Secure the straight-cylindrical shank firmly in the chuck before operation and verify runout before drilling into finished workpieces. Use appropriate cutting fluid for the workpiece material to extend bit life and maintain hole quality. Follow applicable shop safety procedures and wear eye protection during all drilling operations.