Precision Twist Drill 5999041 Jobber Drill Bit Wire 21

Product Description

The PRECISION TWIST DRILL 5999041 is a jobber-length drill bit sized to wire gauge No. 21, with a decimal diameter of 0.1590 inches. Made from high speed steel with a bright uncoated finish, it features a standard 118-degree split point, a tapered web, and a two-flute right-hand spiral for efficient chip evacuation. The overall length is 3.25 inches with a flute length of 2.125 inches, giving a flute-to-diameter ratio of 13xD. It is part of the R18P series and is designed for general-purpose drilling in production and maintenance shop environments.

This bit is suited for drilling steel, stainless steel, cast iron, non-ferrous metals, superalloys, titanium, and other hard materials. It fits standard drill chucks and is used by machinists, maintenance technicians, pipefitters, and sheet-metal workers across light industrial and commercial applications. The straight-cylindrical shank with zero flats seats cleanly in three-jaw chucks. No coolant-through capability is required for typical applications at this diameter.

Key Features

• Wire gauge No. 21 size — 0.1590 inches decimal diameter
• 118-degree standard point angle with web-thinned, tapered web for reduced thrust
• High speed steel construction for general-purpose ferrous and non-ferrous drilling
• Bright uncoated finish — no coating buildup to affect tolerance on small-diameter holes
• Right-hand cut, regular spiral, two-flute design for consistent chip removal
• ANSI standard compliance — Series R10P/R15P/R18P

Compatibility

Designed as a general-purpose jobber-length drill bit for use in standard three-jaw drill chucks and compatible with drill presses, hand drills, and CNC drilling operations requiring a wire-gauge No. 21 or 0.1590-inch diameter hole.

Installation Notes

A licensed machinist or qualified technician should confirm chuck compatibility and runout before use at close-tolerance applications. Secure the shank fully in the chuck to the depth of the straight-cylindrical shank before tightening. For drilling hard materials such as stainless steel or superalloys, use appropriate cutting fluid to extend bit life and maintain hole quality. Do not exceed the maximum drilling depth of 2.125 inches in a single pass without pecking to clear chips.