Precision Twist Drill 5998665 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998665 is a screw machine length drill bit designed for high-performance drilling in demanding industrial and machining applications. Built from high speed steel (HSS) with a coated finish, this bit features a 135-degree split point, web-thinned tip, and a tapered web configuration that reduces walking on entry and lowers feed force. The straight cylindrical shank and spiral flute geometry promote consistent chip evacuation. At 0.041 inches (Wire Size: 59) in diameter with a 1-3/8-inch overall length and a 1/2-inch flute length, this compact bit is sized for short-hole and spot-drilling work where rigidity and precision matter. It meets ANSI and NAS 907 standards and is rated for heavy-duty service.

This bit is well suited for close-tolerance drilling in titanium and other high-strength materials where a stubby, rigid bit reduces deflection. Screw machine length bits are a standard choice on CNC lathes, screw machines, drill presses, and manual machining centers where short overhang is critical. The 2.5xD flute-to-diameter ratio and right-hand spiral flute are matched to aggressive metal removal in production environments. Machinists, toolroom technicians, and precision fabricators working with difficult alloys will find this format reliable for short-run and production drilling alike.

Key Features

• 0.041 inch diameter, Wire Size 59, for precision small-bore drilling
• 135-degree split point with web thinning reduces thrust and prevents walking
• High speed steel construction with coated finish for extended tool life
• Screw machine (stub) length at 1-3/8 inches overall for maximum rigidity
• Right-hand cut, spiral flute with 2.5xD flute ratio for efficient chip evacuation
• Meets ANSI and NAS 907 specifications for heavy-duty, high-performance service

Compatibility

Designed as an OEM-style replacement or production-use screw machine drill bit rated for drilling titanium and comparable high-strength metals; compatible with any machine spindle or chuck accepting a straight cylindrical shank at this diameter.

Installation Notes

Installation and use of this bit should be performed by qualified machinists or toolroom technicians familiar with small-diameter HSS tooling. Secure the straight cylindrical shank firmly in a properly sized collet or drill chuck before operation to prevent runout and bit breakage. At this diameter, use appropriate low feed rates and cutting fluid to manage heat buildup and prolong tool life. Inspect the cutting edges for wear or chipping before each use, as small-diameter bits are susceptible to breakage under side load or excessive feed pressure.