Precision Twist Drill 5998301 Cobalt Jobber Drill 17/64 in

Product Description

The PRECISION TWIST DRILL 5998301 is a cobalt jobber-length drill bit designed for heavy-duty drilling in steel and other demanding workpiece materials. It measures 17/64 inch (0.2656 inch) in diameter with an overall length of 4.125 inches and a flute length of 2.875 inches. The 135-degree split point reduces walking on contact and requires less thrust than a 118-degree point. An oxide and straw coating provides surface protection and helps reduce friction during drilling. This bit is part of the R10CO-R15CO-R18CO series and is installed by machinists, maintenance technicians, and metal fabricators working in production or field environments.

This drill bit is suited for general-purpose drilling in steel and other ferrous and non-ferrous metals. The cobalt steel construction handles higher cutting temperatures than standard HSS, making it appropriate for harder steels and interrupted cuts. With a straight cylindrical shank at 17/64 inch (0.2656 inch) diameter and a 1.25-inch shank length, it seats directly in standard drill chucks found on bench drills, drill presses, and hand drills. It is a general-purpose selection for production shops, maintenance crews, and fabrication applications where steel drilling is routine.

Key Features

• Cobalt steel construction handles elevated cutting temperatures in hard steels
• 135-degree split point reduces thrust requirements and minimizes bit walking
• Oxide and straw coating reduces friction and provides surface protection
• Web-thinned, tapered-web design improves chip evacuation and cutting efficiency
• Regular spiral, 2-flute configuration with right-hand cutting direction
• Meets ANSI and NAS 907 standards for dimensional and performance consistency

Compatibility

Designed for use in standard drill chucks accepting a straight cylindrical shank. Suitable for drilling steel and other primary workpiece materials coded P, M, K, N, and S per the R10CO-R15CO-R18CO series specification. Fits bench drills, drill presses, and hand drills with a compatible chuck capacity.

Installation Notes

Secure the straight shank firmly in a properly sized drill chuck before operation. Ensure the workpiece is clamped or fixtured to prevent movement during drilling. Apply appropriate cutting fluid when drilling steel to manage heat and extend bit life. Inspect the cutting edges for wear before each use, as cobalt bits subjected to excessive heat can develop micro-fractures that are not always visible.