Precision Twist Drill 5998955 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998955 is a screw machine length drill bit designed for high-performance drilling in metal fabrication and machining applications. Built from high speed steel with a bright, uncoated finish, this bit features a 0.339 inch diameter, a 118-degree standard point angle, and a web-thinned, tapered web configuration that reduces cutting resistance at the tip. The straight-cylindrical shank seats securely in standard drill chucks. At 3 inches overall length with a 1-11/16 inch flute length, the screw machine format provides rigidity for accurate, controlled drilling in close-quarter setups. Licensed machinists and tooling technicians rely on this bit for precision work where a jobber-length bit would introduce too much deflection.

This drill bit is rated for use on titanium as its primary workpiece material, making it suitable for aerospace, medical, and industrial machining environments where titanium stock is common. The Series R42 designation identifies it within PRECISION TWIST DRILL's ANSI-conforming screw machine line. The 2.5xD flute-to-diameter ratio and regular spiral flute geometry support effective chip evacuation during short-depth drilling cycles. It is equally applicable to general-purpose ferrous and non-ferrous metal drilling where a stub-length bit is specified.

Key Features

• 0.339 inch diameter, letter size R, within the 0.3000 to 0.3500 inch range
• High speed steel construction rated as high performance general purpose grade
• 118-degree standard point angle with web-thinned tapered web for reduced entry force
• Screw machine (stub) length — 3 inches overall, 1-11/16 inches of flute — for maximum rigidity
• Right-hand cut with regular spiral flutes for efficient chip removal
• Bright, uncoated finish — no coating buildup to affect dimensional tolerance
• Meets ANSI standards; no coolant-through required

Compatibility

Designed as an OEM-style replacement or direct substitute for screw machine length drill bits in the 0.3000 to 0.3500 inch diameter range conforming to ANSI specifications. Fits standard straight-shank drill chucks used in drill presses, CNC machining centers, and hand-held drilling equipment.

Installation Notes

Installation is performed by machinists or tooling technicians using a standard drill chuck sized for straight-cylindrical shanks. Ensure the shank is fully seated and the chuck is tightened securely before operation. Power down the machine and lock out energy sources before changing or inspecting bits. Do not exceed the spindle speed rating appropriate for the workpiece material and bit diameter per standard machining tables.