Precision Twist Drill 5999427 Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5999427 is a screw machine length drill bit designed for high-performance metal cutting in demanding trade and production environments. Built from high speed steel with a coated finish, it features a 135-degree split point and web-thinned tip geometry that reduces walking and cutting force at entry. The straight-cylindrical shank seats securely in standard drill chucks. At 0.2656 inches (17/64 inch) in diameter with an overall length of 2-5/8 inches and a flute length of 1-7/16 inches, this bit fits applications where a standard jobber length would be too long for a close-clearance setup.

This R40C series bit is rated heavy duty and is suited for drilling titanium and other difficult-to-machine materials in production machining, maintenance, and repair operations. The screw machine length profile provides added rigidity compared to jobber-length bits, making it a preferred choice when drilling in fixtures, jigs, or tight machine setups. The regular spiral flute with a 2.5xD flute-to-diameter ratio provides efficient chip evacuation during through-hole and blind-hole operations in both manual and CNC-equipped machines.

Key Features

• 135-degree split point reduces entry walking and lowers required thrust force
• Web-thinned, tapered web configuration improves chip flow and reduces heat buildup
• High speed steel construction with coated finish for extended tool life
• Screw machine length body adds rigidity over standard jobber-length bits
• Right-hand cut with regular spiral flute for standard drilling applications
• Meets ANSI and NAS 907 standards for dimensional and performance consistency

Compatibility

The 5999427 falls within the R40C series drill bit size range of 0.2500 to 0.3000 decimal inches and is rated for use with titanium as the primary workpiece material. It fits any standard drill chuck or collet accepting a straight-cylindrical shank of 17/64 inch diameter.

Installation Notes

This bit is installed by machinists and maintenance technicians using standard drill presses, lathes, or CNC machining centers. Secure the shank fully in the chuck before operation and verify runout is within acceptable limits. When drilling titanium or other hard alloys, use appropriate cutting fluid and reduce feed rate to prevent work hardening. Inspect the cutting edges and point for wear before each use and replace when the split point shows signs of rounding or chipping.