Precision Twist Drill 5998150 Cobalt Jobber Drill 1/8 in

Product Description

The PRECISION TWIST DRILL 5998150 is a cobalt jobber-length drill bit designed for heavy-duty metal drilling applications. Built from cobalt high-speed steel with a straw oxide finish, it resists heat buildup and wear during extended cuts through ferrous and non-ferrous materials. The 135-degree split point reduces walking on entry and requires less thrust than a standard 118-degree point. At 2.75 inches overall length with a 1.625-inch flute, this is a standard jobber proportion suited for bench drill presses, hand drills, and CNC drilling operations. The web-thinned, tapered web configuration improves chip evacuation and cutting efficiency. Licensed machinists, HVAC techs, plumbers, and electricians use bits in this class for drilling through structural steel, pipe, and enclosures.

This bit is sized at 1/8 inch (0.1250 inch decimal) and is configured for right-hand cutting with a regular spiral flute. It is rated for general-purpose drilling in steel, cast iron, aluminum, and other workpiece materials coded P, M, K, N, and S under ISO material classification. The straight cylindrical shank at 0.1250 inch diameter fits standard three-jaw drill chucks without adapters. Series R10CO-R15CO-R18CO identifies this as part of a cobalt-grade line built to NAS 907 and ANSI standards, making it appropriate for aerospace-grade and industrial fabrication work.

Key Features

• Cobalt high-speed steel construction for heat resistance and extended tool life in hard materials
• 135-degree split point reduces thrust requirements and minimizes bit walking on flat surfaces
• Straw oxide finish provides light lubricity and corrosion resistance
• Web-thinned tapered web improves chip flow and reduces cutting friction
• Right-hand, regular spiral flute optimized for general-purpose drilling applications
• Meets NAS 907 and ANSI standards for dimensional and performance consistency

Compatibility

Designed for use in standard three-jaw drill chucks accepting a 1/8-inch straight cylindrical shank. Compatible with drill presses, hand drills, and CNC equipment. Suitable for drilling steel, cast iron, aluminum, and other ISO P, M, K, N, and S workpiece materials. Part of the R10CO-R15CO-R18CO series.

Installation Notes

This bit is installed and serviced by machinists, maintenance technicians, and trade professionals working with metal fabrication or field drilling tasks. Secure the shank fully in a properly sized chuck and verify chuck key is removed before powering on. Use appropriate cutting fluid or lubricant when drilling hardened or thick steel to extend bit life and reduce heat. Do not exceed the recommended maximum drilling depth of 1.625 inches without withdrawing the bit to clear chips.