Precision Twist Drill 5998903 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998903 is a screw machine length drill bit designed for high-performance metal drilling in demanding shop and production environments. Built from high speed steel with a coated finish, this bit measures 0.413 inches (Letter Z) in diameter and features a 135-degree split point for fast, accurate starts with minimal walking. The web-thinned, tapered web construction reduces thrust and improves chip evacuation. At 3-3/8 inches overall length with a 2-inch flute, it is optimized for short-reach, high-precision applications. Licensed machinists, tool-and-die technicians, and metalworking professionals install and use this bit in manual and CNC drill presses.

This screw machine drill bit is built for right-hand cutting with a regular spiral flute pattern and a straight-cylindrical shank for standard chuck compatibility. It is rated for titanium as a primary workpiece material, making it well suited for aerospace, medical, and high-alloy machining environments where tool durability under aggressive feed rates is required. The heavy duty grade and 2.5xD flute-to-diameter ratio support consistent chip clearance during deep-hole operations in hard materials. It meets ANSI and NAS 907 standards and is sold as a single unit.

Key Features

• 0.413 inches (Letter Z) diameter with 135-degree split point for accurate, self-centering entry
• Web-thinned, tapered web reduces drilling thrust and improves chip flow
• High speed steel construction with coated finish for extended tool life
• Screw machine length at 3-3/8 inches overall with 2-inch flute for rigid, close-clearance setups
• Right-hand cut, regular spiral flute — compatible with standard drill chucks via straight-cylindrical shank
• Rated for titanium and other high-performance primary workpiece materials
• Meets ANSI and NAS 907 specifications; heavy duty grade

Compatibility

Designed as a Series R42C screw machine length drill bit conforming to ANSI and NAS 907 standards, suitable for use in manual drill presses, CNC machining centers, and production drilling fixtures that accept a straight-cylindrical shank in the 0.4000 to 0.4500 inch diameter range.

Installation Notes

Installation and use of this drill bit should be performed by qualified machinists or tooling technicians familiar with proper chuck torque and feed-rate settings for the workpiece material. Always power down and lock out the spindle before mounting or removing the bit. Ensure the straight-cylindrical shank is fully seated and secure in the chuck before operation. Follow applicable shop safety standards and machine manufacturer guidelines for speeds and feeds when drilling titanium or other hard alloys.