Precision Twist Drill 5997842 Wire 79 Cobalt Drill Bit

Product Description

The PRECISION TWIST DRILL 5997842 is a wire gauge size 79 cobalt jobber-length drill bit designed for precision drilling in ferrous metals and hard alloys. It features a 135-degree split-point geometry with web thinning, which reduces walking on entry and lowers thrust force required at the spindle. The bit measures 0.75 inches overall with a 0.125-inch flute length and carries a straw oxide finish that provides mild lubricity and heat resistance. Rated as a heavy-duty general-purpose tool, it meets ANSI and NAS 907 standards. Machinists, tool-and-die techs, and maintenance tradespeople reach for this bit when drilling small, tight-tolerance holes in steel and other demanding materials.

This bit is suited for drilling in steel, cast iron, non-ferrous metals, and high-temperature alloys, covering primary workpiece material codes P, M, K, N, and S. The 9xD flute-to-diameter ratio of this jobber-length configuration makes it a practical choice for through-hole operations in thin stock, sheet metal, and precision machined components. It installs into standard drill chucks and collet systems accepting a 0.0145-inch straight cylindrical shank. The series R10CO-R15CO-R18CO designation indicates it is part of PRECISION TWIST DRILL cobalt oxide-finish product lines intended for production and maintenance shop use.

Key Features

• Cobalt high-speed steel construction for drilling steel and hard alloys
• 135-degree split point with web thinning reduces bit walk and feed pressure
• Straw oxide finish adds lubricity and mild corrosion resistance
• Regular spiral, right-hand cutting flute with tapered web configuration
• Meets ANSI and NAS 907 standards for heavy-duty jobber drill classification
• Straight cylindrical shank fits standard drill chucks and collet holders

Compatibility

Designed as a jobber-length replacement drill bit in the PRECISION TWIST DRILL Series R10CO-R15CO-R18CO cobalt oxide-finish line. Compatible with any standard drill chuck or collet system that accepts a 0.0145-inch straight shank.

Installation Notes

Installation and use of this bit should be performed by machinists or qualified tradespeople familiar with machine tool operation and small-diameter bit handling. Ensure the drill press, lathe, or hand drill is fully powered down and the chuck is secured before changing bits. Small-diameter cobalt bits are brittle under side-loading or flex -- use rigid fixturing and appropriate feed rates to avoid breakage. No coolant-through capability; apply cutting fluid externally when drilling steel to extend tool life.