Precision Twist Drill 5999092 Jobber Drill Bit 21 Hss

Product Description

The PRECISION TWIST DRILL 5999092 is a jobber-length twist drill bit designed for general-purpose drilling in a wide range of materials. Built from high speed steel with a steam oxide coating, it carries a wire gauge size of 21, which corresponds to 0.1590 inches in decimal diameter. The 135-degree split point reduces walking on entry and lowers the thrust needed to start a hole, making it well-suited for production drilling environments. Overall length is 3.25 inches with a 2.125-inch flute length. The two-flute spiral design with a tapered web and web-thinned point promotes chip evacuation and keeps the cut clean through the full depth of the hole. Licensed HVAC techs, plumbers, machinists, and general tradespeople reach for this size regularly.

This drill bit is appropriate for use in steel, stainless steel, cast iron, non-ferrous metals, superalloys, titanium, and other hard materials. The straight-cylindrical shank seats in standard three-jaw chucks on hand drills, drill presses, and CNC drilling setups alike. At 0.1590 inches diameter, this wire size 21 bit covers light-to-medium pilot holes, tap drill applications, and clearance holes across residential and commercial trade work. It conforms to ANSI standards and meets NAS 907 specification, making it appropriate for aerospace-adjacent and precision fabrication applications.

Key Features

• Wire size 21 diameter — 0.1590 inches decimal equivalent
• 135-degree standard split point reduces walking and lowers drilling thrust
• High speed steel construction with steam oxide coating for corrosion resistance and lubricity
• Web-thinned, tapered web design promotes chip clearance at depth
• Two spiral flutes with 13xD flute-to-diameter ratio for balanced chip evacuation
• Meets ANSI standards and NAS 907 specification
• Heavy-duty grade suitable for steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium

Compatibility

Designed as a general-purpose jobber-length drill bit compatible with any standard three-jaw chuck or collet accepting a 0.1590-inch straight-cylindrical shank, across hand drills, drill presses, and CNC drilling equipment. Part of the R10B-R15B-R18B series from PRECISION TWIST DRILL.

Installation Notes

This bit is installed by machinists, fabricators, and trade professionals using standard drill chucks — confirm the chuck capacity accommodates a 0.1590-inch shank before seating. Secure the workpiece before drilling and use appropriate cutting fluid when working in stainless steel, superalloys, or titanium to extend bit life. Maximum recommended drilling depth matches the flute length of 2.125 inches — do not exceed this depth in a single pass without retracting to clear chips. Inspect the cutting edges before each use and replace the bit if the point shows signs of wear or chipping.