Precision Twist Drill 5998651 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998651 is a screw machine length drill bit designed for high-performance drilling in demanding trade and industrial applications. Built from high speed steel (HSS) with a coated finish, it measures 0.0465 inches in diameter and features a 135-degree split point angle with web thinning for fast, accurate starts with minimal walking. At 1-3/8 inches overall length with a 1/2-inch flute length, this compact stub-length bit suits tight-clearance drilling situations. Licensed machinists, tool and die workers, and mechanical contractors reach for this bit when precision and repeatability matter most.

This bit is rated for primary use in titanium workpieces and is built to Series R41C specifications, meeting ANSI and NAS 907 standards. The screw machine length format offers added rigidity compared to jobber-length bits, making it a reliable choice in drill press, CNC, and hand-drill applications where chatter and deflection need to be minimized. The right-hand spiral flute evacuates chips efficiently, reducing heat buildup during cuts.

Key Features

• High speed steel construction with coated finish for extended tool life
• 135-degree standard point angle with web thinning for reduced thrust and self-centering entry
• Tapered web configuration with 2.5xD flute-to-diameter ratio for chip clearance
• Screw machine (stub) length adds rigidity and reduces deflection in close-quarters drilling
• Straight-cylindrical shank compatible with standard drill chucks
• Meets ANSI and NAS 907 specifications for heavy duty and high performance applications

Compatibility

Designed as an OEM-style replacement or direct-use screw machine drill bit suitable for standard 3-jaw drill chucks accepting straight-cylindrical shanks; rated for drilling titanium and comparable hard materials per Series R41C specifications.

Installation Notes

Installation and use of this drill bit should be performed by qualified machinists or tradespeople familiar with proper chuck mounting and cutting parameters for HSS tooling. Secure the straight-cylindrical shank fully in the chuck before operation and verify chuck key is removed before powering the drill. Use appropriate cutting fluid or coolant when drilling titanium or hard alloys to manage heat, even though coolant-through is not supported by this bit. Follow shop safety protocols and applicable ANSI machining standards when selecting feed rates and spindle speeds.