Precision Twist Drill 5995805 Cobalt Drill 9/64 in

Product Description

The PRECISION TWIST DRILL 5995805 is a cobalt aircraft extension drill bit designed for demanding drilling applications where standard-length bits cannot reach. Built from cobalt high-speed steel with a straw finish, this bit handles tough, hard, and abrasive materials including stainless steel, titanium, and high-alloy metals. The 135-degree split point is self-centering, eliminating the need for a center punch on most surfaces and reducing walking at startup. The 12-inch overall length gives technicians reach into deep cavities, recessed panels, and structural members. At 9/64 inch (0.1406 inch decimal) diameter with a 1.75-inch spiral flute, it fits the CO500-12 series and meets NAS 907 Type J standards.

This extension drill is suited for aerospace fabrication, HVAC sheet metal work, electrical rough-in, and structural applications where a standard-length bit cannot access the work area. Electricians drilling through deep framing, HVAC installers punching through stacked panels, and aircraft maintenance technicians all use extended-reach cobalt bits like this one. Right-hand cutting direction with a tapered web and web-thinned geometry reduces thrust and chip packing in deep-hole applications. General-purpose performance rating makes it a reliable choice across production and field service environments.

Key Features

• Cobalt construction for heat resistance in hard and abrasive metals
• 135-degree split point with self-centering geometry eliminates pilot punching on most surfaces
• 12-inch overall length provides extended reach into deep or restricted work areas
• Straw finish indicates heat-treated cobalt and aids in chip evacuation
• Web-thinned, tapered web reduces drilling thrust and minimizes bit deflection
• Meets NAS 907 Type J standard for aircraft-grade tooling

Compatibility

Designed as an OEM-compatible replacement or direct addition to cobalt aircraft extension drill sets requiring a 9/64 inch diameter, 12-inch overall length bit. Part of the PRECISION TWIST DRILL CO500-12 series.

Installation Notes

This bit is installed and operated by trained machinists, electricians, HVAC technicians, and aircraft maintenance personnel using standard 3-jaw or keyless drill chucks compatible with a straight-cylindrical shank. Secure the workpiece before drilling and use appropriate cutting fluid when working hardened or stainless alloys to extend bit life and control heat. Inspect the split point before each use and replace the bit if the cutting edges show signs of chipping or heat discoloration. Follow applicable shop safety procedures and any relevant trade codes when drilling into structural or pressurized assemblies.