Precision Twist Drill 5996029 Cobalt Drill Bit 28

Product Description

The PRECISION TWIST DRILL 5996029 is a cobalt aircraft extension drill bit designed for drilling into hard metals and high-strength alloys in demanding industrial and aerospace maintenance applications. Built to Series CO501-6 standards and compliant with NAS 907 Type J, it features a 135-degree split point that is self-centering, reducing the need for a center punch and minimizing walking on hard surfaces. The 0.1405-inch diameter straight-cylindrical shank and web-thinned, tapered web construction promote efficient chip evacuation and reduced thrust during entry. A straw finish indicates the cobalt heat treatment applied during manufacture.

This drill bit is suited for metal fabrication shops, aircraft maintenance facilities, and industrial maintenance environments where standard HSS bits lose edge retention too quickly. The extended 6-inch overall length provides reach into recessed areas or deep fixture setups that a standard-length bit cannot access. Right-hand spiral flutes with a 4xD flute-to-diameter ratio make it appropriate for general-purpose through-hole drilling in ferrous and non-ferrous metals, stainless steel, and titanium alloys at controlled feed rates.

Key Features

• 135-degree split point with self-centering geometry reduces walk-off and eliminates the need for a center punch on most surfaces
• Cobalt tool material with straw finish provides superior heat and wear resistance compared to standard HSS
• NAS 907 Type J compliant for aircraft and aerospace maintenance applications
• Web-thinned tapered web lowers cutting thrust and improves chip flow
• 6-inch overall length gives extended reach for deep or obstructed drilling setups
• Right-hand spiral flutes with 2-flute configuration for efficient chip evacuation

Compatibility

Designed as a general-purpose cobalt extension drill bit for use in standard drill chucks accepting a 0.1405-inch straight-cylindrical shank, suitable for hand-held and machine drilling applications in metalworking and aircraft maintenance environments.

Installation Notes

This drill bit is installed and operated by machinists, tool-and-die technicians, and aircraft maintenance professionals using hand drills, drill presses, or CNC spindles. Ensure the chuck is fully tightened and the shank is clean and free of chips before securing. Use appropriate cutting fluid for the base material to extend tool life and maintain surface finish quality. Always wear eye protection and secure the workpiece before drilling.