Precision Twist Drill 5999421 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5999421 is a screw machine length (stub length) high speed steel drill bit designed for high-performance drilling in demanding production environments. Measuring 0.2031 inches (13/64 inch) in diameter with a 135-degree split point, it starts on contact without a center punch and reduces walking on hard or coated surfaces. The web-thinned, tapered web geometry lowers thrust force and improves chip evacuation. Overall length is 2.25 inches with a 1.1875-inch spiral flute. Right-hand cut with a straight cylindrical shank, this bit is built for machinists, tool-and-die technicians, and maintenance professionals running production drilling operations.

This drill bit is rated for use in titanium as its primary workpiece material, placing it in the high-performance category for difficult-to-machine alloys. The shorter screw machine length body provides greater rigidity compared to jobber-length bits, making it well suited for drill press, CNC, and hand-held power tool applications where chatter and deflection must be minimized. The coated HSS construction adds surface hardness and lubricity for extended tool life in high-cycle production runs. It is sold individually but available in multiples of 12 for shop stocking.

Key Features

• 135-degree split point starts on contact and reduces drill walking without center punching
• Web-thinned, tapered web lowers thrust and improves chip flow
• Screw machine (stub) length body increases rigidity and reduces deflection
• High speed steel construction with coating for extended tool life in hard materials
• Rated for titanium as primary workpiece material, suitable for other hard alloys
• Meets ANSI and NAS 907 standards for dimensional and performance consistency

Compatibility

Designed as an OEM-style replacement or production-stock drill bit for use in standard straight-shank drill chucks on drill presses, CNC machining centers, and hand-held power tools requiring a 0.2031-inch diameter screw machine length bit in the R40C series.

Installation Notes

Installation and use should be performed by qualified machinists or maintenance technicians familiar with rotating cutting tools. Secure the straight cylindrical shank fully in a properly sized drill chuck before operation and verify chuck key is removed before powering the machine. Apply appropriate cutting fluid or coolant at the workpiece when drilling titanium or other hard alloys to control heat buildup, as this bit does not support through-coolant delivery. Inspect the cutting edges for wear or chipping before each use and replace the bit when point geometry degrades to avoid work-hardening the workpiece surface.