Precision Twist Drill 5997888 Cobalt Jobber Drill No. 49

Product Description

The PRECISION TWIST DRILL 5997888 is a cobalt high-speed steel jobber-length drill bit sized to No. 49 wire gauge (0.0730 inches decimal equivalent). It features a 135-degree split point with web thinning for self-centering entry and reduced thrust on hard ferrous materials. The straw oxide finish provides mild lubricity and heat resistance. At 2 inches overall length with a 1-inch flute, this is a short, rigid bit suited for close-quarter drilling in tooling, fixturing, and precision sheet metal work. Licensed machinists, tool-and-die makers, HVAC fabricators, and plumbers working with steel sheet or brackets are the primary users.

This bit is built for general-purpose drilling in steel, stainless, cast iron, aluminum, non-ferrous alloys, and high-temp alloys as indicated by the P, M, K, N, and S workpiece material codes. Typical applications include small-diameter through-hole drilling in structural steel, sheet metal fabrication, and maintenance work where tight tolerances and a clean, accurate entry hole are required. The straight cylindrical shank seats directly in standard drill chucks without adapters.

Key Features

• No. 49 wire size, 0.0730 inch decimal diameter for precise small-bore drilling
• 135-degree split point with web thinning reduces walking and lowers feed pressure
• Cobalt steel construction handles elevated cutting temperatures in hard steels and stainless
• Straw oxide finish adds mild corrosion resistance and lubricity
• Regular spiral, 2-flute design promotes efficient chip evacuation in through-hole drilling
• Meets ANSI and NAS 907 standards for jobber drill geometry and tolerances

Compatibility

Designed as an OEM-style replacement or direct-fit jobber drill for use in standard drill chucks and precision collet holders accepting a 0.0730-inch straight cylindrical shank. Part of the Series R10CO-R15CO-R18CO cobalt jobber line.

Installation Notes

Install in a drill press, hand drill, or CNC spindle using a chuck rated for the shank diameter. Secure the shank fully in the chuck jaws and verify concentricity before running at speed. Use appropriate cutting fluid or oil when drilling steel to extend tool life and maintain hole tolerance. Cobalt bits can be resharpened but require a drill grinder set to the correct 135-degree included angle.