Precision Twist Drill 5998553 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998553 is a screw machine length drill bit designed for high-performance drilling in demanding shop and field applications. Built from high speed steel with a coated finish, this bit features a 0.8438 inch diameter, a 118-degree standard point angle, and a web-thinned tapered web configuration that reduces thrust and improves chip clearance at the point. The straight-cylindrical shank seats securely in standard drill chucks. At 5.375 inches overall length with a 3.5 inch flute length, the screw machine format provides added rigidity over jobber-length bits, making it well suited for close-tolerance work in tight clearances.

This drill bit is rated for primary use on titanium workpieces and is well suited for production environments where a shorter, stiffer bit improves hole location accuracy and reduces deflection. The Series R40 designation places it in PRECISION TWIST DRILL's high performance line, manufactured to ANSI standards. A 2.5xD flute-to-diameter ratio supports efficient chip evacuation during through-hole drilling. Machinists, tool-and-die professionals, and maintenance technicians working with titanium, steel, or other ferrous materials will find this bit a reliable general-purpose option for screw machine and drill press setups.

Key Features

• 0.8438 inch (27/32 inch) diameter, screw machine length for maximum rigidity
• 118-degree standard point angle with web-thinned, tapered web for reduced entry thrust
• High speed steel construction with coated finish for extended tool life
• Right-hand spiral flute with 2.5xD flute-to-diameter ratio for efficient chip removal
• Straight-cylindrical shank fits standard drill chucks without adapters
• Manufactured to ANSI standards, Series R40 high performance designation

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for screw machine, drill press, and CNC drilling operations requiring a 0.8438 inch diameter straight-shank bit conforming to ANSI specifications.

Installation Notes

Installation and use of this drill bit should be performed by qualified machinists or tool operators familiar with proper chuck seating and spindle speed selection for the workpiece material. Ensure the machine spindle is fully stopped and power is locked out before changing bits. Use appropriate cutting fluid or coolant for the workpiece material, particularly when drilling titanium, to prevent work hardening and premature tool wear. Follow applicable shop safety standards and machine manufacturer guidelines for RPM and feed rate settings.