Precision Twist Drill 5996056 No. 34 Cobalt Extension Drill

Product Description

The PRECISION TWIST DRILL 5996056 is a cobalt aircraft extension drill bit designed for drilling in tough materials where standard-length bits fall short. Built to Series CO501-6 specifications, this bit features a 135-degree split point that is self-centering and web-thinned, reducing walking and cutting load on entry. The wire gauge size is No. 34, corresponding to 0.111 inches in decimal. The straight-cylindrical shank seats securely in standard chucks and collets. A straw finish indicates the cobalt steel was heat-treated, contributing to hardness retention at elevated cutting temperatures. Overall length is 6 inches with a 1.5-inch spiral flute, giving extended reach in recessed or deep-hole applications.

This drill bit is suited for aerospace, sheet metal, and general metalworking applications where extended reach is required. The cobalt construction handles stainless steel, high-nickel alloys, hardened steel, and other abrasion-resistant materials that would prematurely dull high-speed steel tooling. Machinists, aircraft maintenance technicians, and metalworking tradespeople use this bit in both handheld drill motors and drill press setups. The 4xD flute-length-to-diameter ratio provides chip clearance on moderate-depth passes.

Key Features

• No. 34 wire gauge size — 0.111 inches decimal diameter
• 135-degree split point with web thinning for self-centering entry and reduced thrust
• Cobalt tool steel construction for elevated heat and wear resistance
• Extended 6-inch overall length for reach in deep or recessed drilling locations
• Straw finish indicating heat-treated cobalt for hardness retention
• Right-hand cutting, 2-flute spiral design with tapered web configuration

Compatibility

Designed as a general-purpose aircraft extension drill bit conforming to NAS 907 Type J standards, suitable for use in standard straight-shank chucks and collets sized for 0.111-inch shanks.

Installation Notes

Installation and use of this drill bit should be performed by a qualified machinist or aircraft maintenance technician familiar with proper cutting speeds and feeds for cobalt tooling. Secure the shank fully in the chuck or collet before operation and verify runout is within acceptable limits. Use appropriate cutting fluid when drilling ferrous or hardened materials to extend tool life and manage heat. Inspect the cutting edges before each use and remove the bit from service if chipping or excessive wear is observed.