Precision Twist Drill 5998176 Cobalt Jobber Drill 3/16 in

Product Description

The PRECISION TWIST DRILL 5998176 is a cobalt jobber-length drill bit designed for production drilling in steel and other demanding workpiece materials. Built to NAS 907 and ANSI standards, this bit features a 135-degree split point with web thinning for fast starts without center-punching and reduced thrust on hard stock. The straw oxide finish provides light lubricity and heat resistance during high-speed drilling cycles. At 3.5 inches overall length with a 2.3125-inch flute, it delivers the reach and chip clearance needed for through-hole work in plate, structural members, and fabricated assemblies. A straight cylindrical shank fits standard Jacobs-style and keyless chucks without adapters.

This drill bit is suited for drilling operations in steel, cast iron, nonferrous alloys, and similar materials — corresponding to workpiece material codes P, M, K, N, and S. Typical applications include production shops, maintenance and repair, HVAC equipment fabrication, plumbing rough-in metalwork, and electrical panel fabrication where hole quality and bit longevity in ferrous stock are priorities. The cobalt construction and heavy-duty grade make it appropriate for harder alloys that would quickly degrade standard high-speed steel bits.

Key Features

• Cobalt construction for increased heat resistance and durability in ferrous and hard alloy drilling
• 135-degree split point with web thinning reduces walking and lowers drilling thrust
• Straw oxide finish provides light lubricity and corrosion resistance during service
• Regular spiral, 2-flute design promotes efficient chip evacuation in through-hole drilling
• Straight cylindrical shank fits standard drill chucks without sleeves or adapters
• Meets NAS 907 and ANSI standards for consistent dimensional tolerances

Compatibility

Designed as an OEM-style replacement or standard-stock jobber drill bit for use in any 3/16-inch capable drill chuck in handheld, bench, or mill applications. Part of the R10CO-R15CO-R18CO series.

Installation Notes

Installation is performed by machinists, fabricators, and trade technicians using standard drill presses, handheld drills, or milling machines. Secure the shank firmly in a properly sized chuck before operation and verify chuck key is removed before starting the spindle. Apply cutting fluid or oil when drilling hard steel or stainless alloys to extend bit life and maintain hole quality. Inspect the cutting edges and web area for wear or chipping before each use and replace if the point geometry is compromised.