Precision Twist Drill 5998906 Drill Bit Letter S Hss

Product Description

The PRECISION TWIST DRILL 5998906 is a jobber-length drill bit sized to Letter S (0.3480 inches) designed for general-purpose drilling in metal and hard materials. Built from high-speed steel with a bright uncoated finish, it features a standard 118-degree split point and a tapered web-thinned core that reduces thrust and improves chip evacuation. The straight-cylindrical shank measures 0.3480 inches in diameter, making it compatible with standard drill chucks. With an overall length of 4.875 inches and a 3.5-inch spiral flute, this bit is suited for production and maintenance drilling where consistent hole diameter and clean entry are required.

This drill bit is intended for use on steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium. It fits the R10P-R15P-R18P series and is appropriate for machine shop, fabrication, and field service applications. The regular spiral flute geometry suits a wide range of rotational speeds and feed rates typical in drilling through ferrous and non-ferrous stock. Licensed trades including machinists, millwrights, pipefitters, and HVAC-R mechanics commonly use jobber-length bits in this size range for tapping preparation, conduit work, and bracket fabrication.

Key Features

• Letter S size — 0.3480 inches decimal equivalent for precise hole sizing
• 118-degree standard point angle with web-thinned, tapered web for reduced entry force
• High-speed steel construction handles steel, stainless steel, cast iron, and titanium
• 2-flute regular spiral design promotes efficient chip clearing
• Straight-cylindrical shank fits standard keyless and keyed drill chucks
• ANSI-conforming geometry and tolerances for consistent, repeatable performance

Compatibility

Part of the R10P-R15P-R18P series. Designed as a general-purpose jobber-length drill bit suitable for use in standard drill presses, CNC drilling centers, and handheld power drills equipped with a 3/8-inch or larger chuck accepting a 0.3480-inch straight shank.

Installation Notes

Install in a properly sized drill chuck and tighten securely before operation. Ensure the workpiece is clamped or fixtured to prevent movement during drilling. Use appropriate cutting fluid or coolant when drilling stainless steel, superalloys, or titanium to extend tool life and manage heat buildup. Inspect the cutting edges for wear or chipping before each use and replace the bit if the point shows visible damage.