Precision Twist Drill 5996100 Cobalt Aircraft Extension Drill

Product Description

The PRECISION TWIST DRILL 5996100 is a cobalt aircraft extension drill bit designed for drilling into hard metals and alloys where standard high-speed steel bits fall short. Built to NAS 907 Type J standards, this wire gauge size 12 bit measures 0.1890 inches in diameter with a 6-inch overall length, giving technicians added reach in deep or obstructed bore locations. The 135-degree split point is self-centering and web-thinned, reducing the pressure needed to start a hole without a center punch. The straw finish indicates a cobalt substrate heat treatment and provides light surface protection. Licensed tradespeople and aerospace maintenance technicians are the primary installers of this bit.

This drill bit is suited for aircraft maintenance, sheet metal fabrication, and general metalworking applications where extended reach is required. The 2.3125-inch flute length supports chip evacuation in deeper cuts, while the straight-cylindrical shank seats securely in standard three-jaw chucks and collet holders. The series CO501-6 designation places this bit in a line of general-purpose cobalt extension drills optimized for right-hand cutting in ferrous and non-ferrous materials at conventional drill press or hand drill speeds.

Key Features

• Cobalt tool material for improved heat and wear resistance in hard metals
• 135-degree split point is self-centering and reduces walking on entry
• Web-thinned, tapered web configuration lowers thrust requirements
• 6-inch overall length provides extended reach for deep or confined bore locations
• Straw finish heat treatment indicator; right-hand spiral flute cutting direction
• Meets NAS 907 Type J standards for aircraft and aerospace drilling applications

Compatibility

Designed as an OEM-style replacement or direct-use cobalt extension drill bit for applications requiring a wire gauge size 12 (0.1890 inch) diameter in standard three-jaw chucks or collet-style drill holders.

Installation Notes

Install into a properly rated drill press, hand drill, or pneumatic drill with a compatible chuck or collet rated for the shank diameter. Power down and secure the workpiece before changing or seating the bit. Use appropriate cutting fluid when drilling hard alloys to extend bit life and manage heat buildup. Follow applicable workplace safety standards and manufacturer guidance for drill speed selection based on material type and bit diameter.