Precision Twist Drill 5998228 Cobalt Jobber Drill Bit 9/16 in

Product Description

The PRECISION TWIST DRILL 5998228 is a 9/16 inch cobalt jobber-length drill bit designed for heavy-duty drilling in ferrous and non-ferrous metals. Built from high-speed cobalt steel with an oxide and straw finish, it delivers extended tool life in demanding applications. The 135-degree split point reduces walking on entry and requires less axial force than a standard 118-degree point. A web-thinned, tapered web design further reduces cutting resistance. This bit ships individually and is intended for use by machinists, maintenance technicians, pipefitters, and metalworkers running standard drill presses, magnetic drills, or hand-held power tools.

The 5998228 is rated for general-purpose drilling in steel, cast iron, aluminum, copper, and other workpiece materials covered under material codes P, M, K, N, and S. With a 4-13/16 inch flute length and 6-5/8 inch overall length, it handles through-hole and deep-hole work up to 4.8125 inches depth of cut. The straight cylindrical shank fits standard 9/16 inch chuck capacity. This bit conforms to NAS 907 and ANSI standards, making it appropriate for aerospace and industrial maintenance environments where specification compliance is required.

Key Features

• Cobalt high-speed steel construction for heat and wear resistance in hard materials
• 135-degree split point reduces thrust and eliminates center-punch requirement on most metals
• Oxide and straw coating provides lubricity and corrosion resistance during cutting
• Web-thinned tapered web lowers cutting torque and chip-packing risk
• Regular spiral flute geometry promotes efficient chip evacuation in through-hole drilling
• Meets NAS 907 and ANSI standards for use in specification-controlled applications

Compatibility

Designed for use in standard drill chucks accepting a 9/16 inch straight cylindrical shank. Suitable for drilling steel and other metallic workpiece materials classified under P, M, K, N, and S material codes. Part of the R10CO-R15CO-R18CO series from PRECISION TWIST DRILL.

Installation Notes

Installation and use should be performed by qualified machinists or maintenance technicians familiar with rotating cutting tool safety. Secure the workpiece firmly before drilling and confirm chuck tightness before operation. Wear appropriate eye and hand protection per shop safety requirements. Do not exceed the rated maximum drilling depth of 4.8125 inches and apply cutting fluid when drilling hard or thick steel stock to manage heat buildup.