Precision Twist Drill 5998220 Cobalt Jobber Drill 7/16 in

Product Description

The PRECISION TWIST DRILL 5998220 is a cobalt jobber-length drill bit designed for heavy-duty drilling in steel and other demanding workpiece materials. Built to NAS 907 and ANSI standards, it features a 135-degree split point with web thinning for faster penetration and reduced walking on entry. The straw oxide finish provides added surface hardness and corrosion resistance. At 5.5 inches overall length with a 4.0625-inch flute length, it fits standard drill chucks without adapters. This bit is suited for use by machinists, pipefitters, electricians, and HVAC technicians who need reliable performance drilling through ferrous metals in the field or shop.

This jobber drill bit is built for general-purpose drilling in steel, cast iron, aluminum, and similar materials. The regular spiral flute with tapered web configuration provides efficient chip evacuation during through-hole and blind-hole operations. The straight cylindrical shank measures 7/16 inches in diameter, making it compatible with standard keyed and keyless drill chucks. The 9xD flute-to-diameter ratio is consistent with standard jobber-length geometry, appropriate for a wide range of production and maintenance drilling tasks across mechanical, HVAC, plumbing, and electrical trades.

Key Features

• Cobalt construction rated for heavy-duty drilling in ferrous and hard materials
• 135-degree split point with web thinning reduces thrust and prevents bit walking
• Straw oxide finish improves surface hardness and extends tool life
• Regular right-hand spiral flute promotes efficient chip removal
• Straight cylindrical shank at 7/16 inches fits standard drill chucks directly
• Meets NAS 907 and ANSI specifications for consistent dimensional accuracy

Compatibility

Part of the R10CO-R15CO-R18CO series. Designed for general-purpose drilling in steel, cast iron, stainless, aluminum, and similar primary workpiece materials with material codes P, M, K, N, and S. Fits any drill press, hand drill, or magnetic drill motor accepting a 7/16-inch straight shank.

Installation Notes

Secure the shank firmly in the chuck and verify concentricity before drilling to avoid runout. Always use appropriate cutting fluid or coolant when drilling hardened steel or stainless to prevent heat buildup that can degrade the cobalt cutting edge. Power down and lock out any drill press before changing bits. Follow shop safety protocols and applicable ANSI machining guidelines when operating at high RPM.