Precision Twist Drill 5999099 Letter F Jobber Drill Bit

Product Description

The PRECISION TWIST DRILL 5999099 is a jobber length drill bit sized to Letter F, equivalent to 0.2570 inches decimal, manufactured from high speed steel with a steam oxide coating. It features a standard 118-degree drill point angle, a 2-flute spiral flute configuration with a regular spiral type, and a right-hand cutting direction. The straight-cylindrical shank diameter measures 0.2570 inches. Overall length is 4.125 inches, with a flute length of 2.875 inches. The tapered web with web-thinned geometry reduces thrust during entry. Licensed HVAC technicians, machinists, and general tradespeople who drill through metal substrates will recognize this as a general-purpose workhorse bit suited for production and maintenance drilling.

This bit is rated for use in steel, stainless steel, cast iron, non-ferrous metals, superalloys, titanium, and other hard materials, covering ISO material codes P, M, K, N, and S. It fits standard jobber-length drill applications where a flute-to-diameter ratio of 11xD provides adequate chip clearance and reach. The Series R10-R15-R18 designation places it within a family of general-purpose HSS bits designed for consistent performance across light production and maintenance drilling scenarios. No coolant-through capability is present, so external coolant or cutting fluid is recommended when drilling harder alloys.

Key Features

• Letter F sizing at 0.2570 inches decimal for precise hole diameter
• 118-degree standard point angle for general-purpose metal drilling
• Steam oxide coating reduces friction and provides light corrosion resistance during storage
• Web-thinned, tapered web geometry lowers drilling thrust and improves bit life
• 2-flute regular spiral design promotes chip evacuation in through-hole and blind-hole applications
• Straight-cylindrical shank compatible with standard 3-jaw drill chucks and keyed chuck systems
• Conforms to ANSI standards for jobber length drill geometry

Compatibility

Designed as an OEM-style jobber length drill bit for use in any standard drill press, hand drill, or machining center equipped with a chuck accepting a 0.2570-inch straight-cylindrical shank. Suitable for drilling steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium per Series R10-R15-R18 application guidelines.

Installation Notes

Machinists, maintenance technicians, and tradespeople install this bit by seating the straight shank fully into a keyed or keyless chuck and tightening securely before operation. Ensure the workpiece is clamped or fixtured to prevent rotation during drilling. When working with harder alloys such as stainless steel or titanium, apply cutting fluid to reduce heat buildup and extend bit life. Inspect the cutting edges for wear before each use and replace the bit if chipping or rounding is observed.