Precision Twist Drill 6001394 No. 42 Hss Extension Drill

Product Description

The PRECISION TWIST DRILL 6001394 is a No. 42 wire-size aircraft extension drill bit engineered for deep-reach drilling applications where standard-length bits cannot access the work area. Built from high speed steel with an oxide finish, this bit measures 12 inches in overall length with a 1.25-inch spiral flute. The 135-degree split point is self-centering and web-thinned, reducing walking on entry and lowering feed force on hard or layered materials. Two right-hand flutes evacuate chips efficiently during extended-reach operations. The straight-cylindrical shank measures 0.093 inches in diameter for secure chuck engagement.

This extension drill is suited for aerospace, sheet metal, and general fabrication work where access depth is a constraint. The aircraft extension designation makes it a common choice when drilling through structural assemblies, deep cavities, or stacked materials that standard jobber-length bits cannot reach. General-purpose tool performance ratings make it appropriate across a wide range of ferrous and non-ferrous base materials encountered in professional trade and production environments. It is sized to the No. 42 wire gauge standard, corresponding to a decimal diameter of 0.0935 inches.

Key Features

• No. 42 wire size, 0.0935-inch cutting diameter for precision small-diameter work
• 12-inch overall length provides extended reach into deep or restricted areas
• 135-degree split point is self-centering and reduces thrust force on entry
• Web-thinned, tapered web configuration lowers drilling torque and improves chip clearance
• Oxide finish on high speed steel body for basic wear and lubrication retention
• Meets NAS 907 Type B standard for aircraft-grade drill bit performance

Compatibility

Designed as a general-purpose aircraft extension drill bit compatible with standard drill chucks and collets accepting a 0.093-inch straight-cylindrical shank, suitable for use in hand drills, drill presses, and pneumatic drilling equipment.

Installation Notes

Installation and use of this drill bit should be performed by machinists, sheet metal mechanics, or qualified trade professionals familiar with small-diameter bit handling. Secure the straight-cylindrical shank fully in the chuck before operation and confirm the workpiece is clamped or fixtured. Small-diameter bits are susceptible to breakage under side load or misalignment — maintain axial alignment throughout the drilling stroke. Apply appropriate cutting fluid for the base material to extend bit life and improve hole quality.