Precision Twist Drill 5998912 Jobber Drill Bit Letter T

Product Description

The PRECISION TWIST DRILL 5998912 is a jobber-length drill bit sized to Letter T, equal to 0.3580 inches in diameter, made from high speed steel with a bright uncoated finish. It features a standard 118-degree point angle, a two-flute regular spiral design, and a web-thinned tapered web for reduced thrust when starting holes. Overall length is 4.875 inches with a flute length of 3.5 inches, giving it the reach needed for general-purpose through-hole and blind-hole work. Licensed HVAC technicians, machinists, plumbers, and electricians reach for this bit when drilling through steel, stainless steel, cast iron, non-ferrous metals, and similar hard materials in the field or shop.

This bit is suited for production and maintenance drilling in both residential and commercial settings. It fits standard three-jaw drill chucks accepting a 0.3580-inch straight cylindrical shank. Typical applications include drilling pilot and clearance holes in ferrous and non-ferrous structural material, equipment enclosures, conduit hangers, and mechanical supports. The Series R10P-R15P-R18P designation places it in a proven general-purpose jobber family built to ANSI specification. One bit per package.

Key Features

• Letter T size — 0.3580 inches diameter, ANSI-compliant jobber length
• 118-degree standard point angle with web-thinned tapered web for easier hole starting
• High speed steel construction rated for steel, stainless steel, cast iron, non-ferrous metals, and superalloys
• Two-flute regular spiral, right-hand cut — compatible with standard drill presses and hand drills
• Straight cylindrical shank with 0 flats for secure chuck retention
• Bright uncoated finish — suitable for use with cutting fluid on harder materials

Compatibility

Designed as a general-purpose jobber-length drill bit for use in any standard drill press or portable drill accepting a straight cylindrical shank up to 0.3580 inches. Confirmed workpiece material compatibility includes steel, stainless steel, cast iron, non-ferrous metal, superalloys, and titanium per supplier material codes P, M, K, N, and S.

Installation Notes

A licensed machinist or qualified trades professional should secure the shank fully in a properly rated three-jaw chuck before operation. Always power down and de-energize the drill press or tool before changing bits. Use appropriate cutting fluid when drilling stainless steel, superalloys, or titanium to manage heat and extend bit life. Do not exceed the maximum drilling depth of 3.5 inches per pass without clearing chips.