Precision Twist Drill 5995679 Cobalt Drill Bit Set

Product Description

The PRECISION TWIST DRILL 5995679 is a 115-piece cobalt jobber length drill bit set designed for demanding metal-cutting applications in industrial and trade environments. The set covers fractional sizes from 1/16 inch to 1/2 inch in 1/64-inch step increments, plus letter sizes A through Z. Each bit is manufactured from cobalt high-speed steel with a gold finish and features a 135-degree split-point tip that reduces walking on contact, requires no center punch on most surfaces, and cuts through hardened steels, stainless, and cast iron with less heat buildup than standard HSS. Straight shanks are compatible with standard three-jaw chucks. Bits conform to ANSI standards and are stored in a metal index case.

This set suits professional machinists, pipefitters, fabricators, maintenance mechanics, and HVAC or plumbing technicians who regularly drill through structural steel, stainless fastener stock, copper pipe hangers, and similar hard materials. The fractional range from 1/16 inch through 1/2 inch in 1/64-inch increments covers the majority of hole sizes encountered in mechanical, sheet-metal, and rough-in work. The included letter-size bits extend versatility for tap-drill and reaming applications. The metal index case keeps bits organized and protects cutting edges between uses on the job site or in the shop.

Key Features

• Cobalt high-speed steel construction for extended life in hard and abrasive metals
• 135-degree split-point tip starts on contact without center punching and reduces thrust requirements
• Gold finish provides visual wear indicator and mild lubricity
• 115-piece set covers fractional sizes 1/16 to 1/2 inch and letter sizes A through Z in 1/64-inch steps
• Straight shank fits standard drill chucks and magnetic drill press adapters
• ANSI-compliant jobber length geometry balances rigidity and reach for general-purpose drilling
• Metal index case with labeled slots for quick bit identification and secure storage

Compatibility

Bits in this set belong to Series R10CO, R15CO, and R18CO from PRECISION TWIST DRILL. Straight shanks are compatible with any standard three-jaw drill chuck accepting shanks up to 1/2 inch. Intended for use in bench drill presses, hand drills, and magnetic drills used in metal fabrication and mechanical trade applications.

Installation Notes

These drill bits are installed and serviced by machinists, maintenance mechanics, and licensed trade professionals working with drill presses or portable drilling equipment. Secure the workpiece firmly before drilling and use appropriate cutting fluid or lubricant when drilling hardened steel or stainless to extend bit life. Inspect bits for chipping or dulling before each use, and replace any bit that shows signs of edge degradation to avoid workpiece damage or breakage. Always follow ANSI machine guarding requirements and wear appropriate eye protection when operating drilling equipment.