Precision Twist Drill 5999436 Drill Bit Letter X Hss

Product Description

The PRECISION TWIST DRILL 5999436 is a jobber-length drill bit sized to Letter X (0.3970 inches decimal), manufactured from high speed steel with a steam oxide coating for improved lubricity and basic corrosion resistance. It features a 118-degree standard point angle, a two-flute regular spiral configuration, and a web-thinned, tapered web for reduced thrust during entry. Overall length is 5.125 inches with a 3.75-inch flute length and a straight-cylindrical shank of 0.3970 inches diameter. This is a general-purpose drilling tool suited for production and maintenance shops where reliable, consistent hole quality is required across a range of workpiece materials.

This drill bit is designed for drilling steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium. It fits standard drill chucks without modification due to its straight-cylindrical shank. Typical use cases include fabrication, MRO maintenance, and field service work where a Letter X diameter hole is required for tapping, reaming prep, or clearance fits. The 9xD flute-to-diameter ratio provides adequate chip evacuation in through-hole and moderate-depth drilling applications up to 3.75 inches maximum depth.

Key Features

• Letter X size: 0.3970 inches decimal equivalent for precise sizing
• 118-degree standard point angle with web thinning for reduced entry thrust
• Steam oxide coating improves lubricity and provides basic corrosion protection
• Two-flute regular spiral design supports efficient chip evacuation
• Straight-cylindrical shank fits standard drill chucks without adapters
• Conforms to ANSI standards for jobber-length drill bit geometry

Compatibility

Designed as a general-purpose jobber-length drill bit compatible with standard three-jaw drill chucks and drill presses, CNC machining centers, and hand-held power drills that accept straight-shank tooling up to 0.3970 inches in diameter. Suitable for workpiece materials coded P, M, K, N, and S per ISO material classification.

Installation Notes

Installation is performed by machinists, tool-and-die technicians, maintenance mechanics, or other trades requiring precision drilling. Secure the shank fully within the chuck jaws to the recommended grip depth before tightening. Ensure the workpiece is clamped or fixtured securely to prevent rotation or movement during drilling. Do not exceed the maximum drilling depth of 3.75 inches, and retract periodically to clear chips when drilling deep holes or gummy materials.