Precision Twist Drill 5998919 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998919 is a screw machine length drill bit designed for high-performance drilling in metal and hard materials. Built from high speed steel (HSS) with a bright/uncoated finish, this bit measures 0.261 inches in diameter and carries a standard 118-degree point angle. The overall length is 2-5/8 inches with a flute length of 1-7/16 inches, making it a compact stub-length tool suited for close-quarters work. Web-thinned construction reduces thrust and improves chip flow. Licensed machinists, tool-and-die technicians, and maintenance mechanics are the primary users.

This drill bit is engineered for use in screw machine operations, CNC drilling setups, and general-purpose production environments. The R42 series is rated for high performance applications and is listed by the manufacturer as suitable for titanium as a primary workpiece material, making it a capable choice for aerospace, medical, and precision machining workflows. The straight-cylindrical shank fits standard three-jaw chucks and collet holders without modification. The 2.5xD flute-to-diameter ratio supports efficient chip evacuation in short-hole drilling cycles.

Key Features

• 0.261 inch diameter with a standard 118-degree point angle for accurate entry in metal stock
• High speed steel construction provides heat resistance during high-cycle drilling
• Web-thinned, tapered web design reduces cutting thrust and improves penetration
• Bright/uncoated finish allows visual inspection of wear and edge condition
• Straight-cylindrical shank fits standard chucks and collet systems
• ANSI-compliant screw machine length for use in tight clearance setups

Compatibility

Designed as a screw machine length replacement or production drill bit in Series R42, sized for general purpose drilling in the 0.2500 to 0.3000 inch decimal inch range per ANSI standards. Primary workpiece material listed by the manufacturer is titanium, though the general purpose grade is compatible with a range of metals in typical shop use.

Installation Notes

Installation and use of this drill bit should be performed by qualified machinists or tool operators familiar with drilling parameters for the target workpiece material. Secure the straight-cylindrical shank fully in the chuck or collet before operation and confirm runout is within tolerance. Coolant-through is not supported on this bit, so apply cutting fluid externally when drilling titanium or other difficult alloys. Follow applicable shop safety standards and machine manufacturer guidelines for spindle speed and feed rate selection.