Precision Twist Drill 5995556 Cobalt Extension Drill No.9

Product Description

The PRECISION TWIST DRILL 5995556 is a cobalt aircraft extension drill bit designed for drilling in hard metals, stainless steel, and high-temperature alloys where standard high-speed steel bits fall short. It carries a No. 9 wire gauge size with a decimal diameter of 0.196 inches and a 135-degree split point that self-centers on contact, reducing the need for a center punch. The straw finish indicates heat-treated cobalt steel construction. At 6 inches overall length with a 2.4375-inch flute length, it provides extended reach into deep holes and recessed surfaces that shorter jobber-length bits cannot access. Licensed trade professionals and aerospace MRO technicians are the primary users of this tool.

This drill bit is suited for aircraft-grade metalworking applications requiring extended reach, including airframe repair, structural drilling, and general-purpose production drilling in ferrous and non-ferrous materials. The two-flute spiral design with a tapered web and web-thinned geometry promotes chip evacuation in deep-hole drilling scenarios. It is manufactured to NAS 907 Type J standards, making it appropriate for aviation maintenance and precision fabrication environments. The straight-cylindrical shank seats in standard drill chucks and right-angle drill attachments without modification.

Key Features

• Cobalt tool material with straw finish for heat and wear resistance in hard metals
• 135-degree split point with self-centering geometry eliminates pilot hole requirement
• Extended 6-inch overall length provides reach into recessed and deep-hole locations
• Web-thinned tapered web reduces thrust and improves chip flow
• Right-hand cutting, two-flute spiral design for standard drill press and hand-drill use
• Manufactured to NAS 907 Type J standards for aerospace and precision applications

Compatibility

Designed as a general-purpose aircraft extension drill bit compatible with any drill press, handheld drill, or right-angle drill with a standard chuck accepting a 0.196-inch straight-cylindrical shank. Conforms to Series CO501-6 specifications.

Installation Notes

Installation and use should be performed by qualified machinists, aircraft maintenance technicians, or trade professionals familiar with metalworking drill bit operation. Secure the straight-cylindrical shank firmly in a properly sized chuck before use and verify chuck tightness before engaging the workpiece. Always wear appropriate eye protection and use cutting fluid or lubricant when drilling hard alloys to extend bit life and reduce heat buildup. Do not exceed recommended feed rates for cobalt tooling in the material being drilled.