Precision Twist Drill 5999059 Letter Q Cobalt Jobber Drill

Product Description

The PRECISION TWIST DRILL 5999059 is a Letter Q cobalt jobber-length drill bit designed for heavy-duty drilling in ferrous and non-ferrous metals. It carries a 135-degree split point that reduces walking on entry and cuts faster than a standard 118-degree point. The bit measures 4.75 inches overall with a 3.4375-inch flute length and is finished with an oxide and straw coating to improve lubricity and heat resistance. The straight cylindrical shank fits standard drill chucks without modification. This bit is a general-purpose production tool suited for machine shop, maintenance, and field drilling work performed by machinists, pipefitters, ironworkers, and millwrights.

Letter Q corresponds to a decimal diameter of 0.3320 inches, making it a common choice when drilling tap holes and clearance holes in steel plate, structural steel, and alloy materials. The web-thinned, tapered-web construction reduces thrust load at the cutting edge, which extends bit life in repetitive drilling applications. The 10xD flute-to-diameter ratio provides adequate chip evacuation without sacrificing rigidity. This bit meets ANSI and NAS 907 standards, confirming dimensional and performance consistency for production environments.

Key Features

• Letter Q size — 0.3320-inch decimal diameter for precise hole sizing
• 135-degree split point reduces bit walk and lowers entry thrust
• Cobalt high-speed steel construction handles elevated cutting temperatures in hard steels
• Oxide and straw finish improves lubricity and extends tool life
• Web-thinned, tapered web reduces cutting resistance in deep-hole drilling
• Meets ANSI and NAS 907 standards for dimensional conformance

Compatibility

Designed for use in standard drill chucks accepting a 0.3320-inch straight cylindrical shank. Rated for drilling steel, stainless, cast iron, aluminum, and other materials within the P, M, K, N, and S workpiece material classifications. Belongs to Series R10CO-R15CO-R18CO.

Installation Notes

This bit is installed by machinists and trade professionals using drill presses, magnetic drills, or portable electric drills with a compatible chuck. Secure the shank fully in the chuck and confirm concentricity before cutting to prevent runout. Use appropriate cutting fluid when drilling steel or stainless to extend bit life and maintain cut quality. Wear appropriate eye protection and secure workpieces before drilling operations begin.