Precision Twist Drill 6001348 Letter Y Aircraft Extension Drill

Product Description

The PRECISION TWIST DRILL 6001348 is a Letter Y aircraft extension drill bit engineered for deep-hole drilling in aerospace and industrial applications. Built from high speed steel with an oxide finish, it features a 135-degree split point that self-centers on contact, eliminating the need for a center punch on most surfaces. The two-flute spiral design and web-thinned, tapered web configuration promote aggressive chip evacuation during extended cuts. With a 0.404-inch diameter straight-cylindrical shank and a flute length of 3.875 inches within a 6-inch overall length, this bit is suited for drilling in tight or recessed locations where a standard-length drill cannot reach. Licensed trades and aerospace MRO technicians are the primary installers.

This drill bit is designed for general-purpose drilling in metal, aluminum, and structural materials where an extended reach is required. The Series 502-6 classification places it in the aircraft extension category, making it appropriate for airframe work, fabrication shops, and heavy industrial environments where hole depth or obstruction clearance exceeds the reach of standard jobber-length bits. The Letter Y size corresponds to a 0.404-inch decimal diameter, commonly used for tapping and close-tolerance bore applications.

Key Features

• 135-degree split point self-centers and reduces walking on entry without a pilot hole
• High speed steel construction provides durability across a range of metals and hard materials
• Oxide finish improves lubricity and surface hardness for extended tool life
• Web-thinned tapered web lowers thrust force and improves chip clearance in deep cuts
• 3.875-inch flute length within a 6-inch overall length delivers extended reach in confined areas
• Right-hand cutting, two-flute spiral design compatible with standard drill press and hand-drill operation

Compatibility

Designed as an OEM-style aircraft extension drill bit conforming to NAS 907 Type B standards, suitable for use in any compatible right-hand-drive drill press, magnetic drill, or handheld drill motor accepting a 0.404-inch straight-cylindrical shank.

Installation Notes

Installation of this bit is performed by machinists, aircraft mechanics, or licensed tradespeople using appropriate drill equipment. Secure the shank firmly in a chuck rated for the shank diameter before operation, and verify the workpiece is clamped or fixtured to prevent movement. Apply cutting fluid appropriate to the base material to extend bit life and improve hole finish. Inspect the split point for wear or chipping before each use, as a damaged point will reduce centering accuracy and increase the risk of bit breakage.