Precision Twist Drill 5997666 Jobber Drill Bit No. 8

Product Description

The PRECISION TWIST DRILL 5997666 is a jobber-length twist drill bit in wire gauge size No. 8, equivalent to 0.1990 inches in decimal. It is manufactured from high speed steel with a steam oxide coating that reduces friction and provides basic corrosion resistance during storage and use. The 135-degree split point reduces the tendency to walk on entry and requires no center punch on most metals. With an overall length of 3.625 inches and a spiral flute length of 2.4375 inches, this bit handles general-purpose drilling tasks in a wide range of shop and field applications. Licensed machinists, maintenance technicians, and pipefitters are the typical end users.

This drill bit is designed for drilling steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium. It is suited for production drilling environments as well as maintenance and repair work on mechanical equipment. The regular spiral flute and web-thinned, tapered web geometry aid chip evacuation in deep-hole conditions up to the maximum drilling depth of 2.4375 inches. The straight cylindrical shank fits standard three-jaw chucks on drill presses, hand drills, and milling machine spindles without an adapter.

Key Features

• Wire gauge No. 8 diameter — 0.1990 inches decimal equivalent
• 135-degree standard point angle with web thinning for reduced thrust and clean entry
• High speed steel construction rated for heavy-duty general-purpose use
• Steam oxide coating provides lubricity and light corrosion protection
• Spiral flute with tapered web design promotes efficient chip evacuation
• Meets ANSI standards and NAS 907 specification designation

Compatibility

Designed as an OEM-style replacement or direct equivalent for wire gauge No. 8 jobber-length drill bits in Series R10B, R15B, and R18B from PRECISION TWIST DRILL. Fits any standard three-jaw chuck accepting a 0.1990-inch straight cylindrical shank.

Installation Notes

This bit should be installed by a qualified machinist or maintenance technician familiar with rotating cutting tools. Secure the straight shank fully in the chuck and verify runout before beginning a cut. Always power down and lock out the machine spindle before changing bits. Use appropriate cutting fluid or coolant for stainless steel and superalloy materials to extend tool life, as coolant-through is not supported on this bit.