Precision Twist Drill 5995934 Cobalt Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5995934 is a cobalt screw machine length drill bit designed for high-performance drilling in hard and abrasive materials. Built to M40CO series specifications, it features a 135-degree split point for fast penetration and reduced walking on entry, along with a web-thinned, tapered web construction that lowers thrust and improves chip clearance. At 0.6875 inches (11/16 inch) in diameter with a straight-cylindrical shank and regular spiral fluting, this bit is suited for use in drill presses, CNC machines, and screw machine operations where precision and durability under load are required. Installation is handled by machinists and toolroom technicians.

This bit is optimized for drilling hard materials including alloy steels, stainless steels, and other high-strength workpieces where standard high-speed steel tooling falls short. The screw machine length profile — shorter than jobber length — provides added rigidity and reduced deflection, making it well suited for production drilling environments, tight machine setups, and applications where hole location accuracy is critical. The 2.5xD flute-to-diameter ratio supports efficient chip evacuation across a range of feed and speed conditions.

Key Features

• Cobalt construction (M40 grade) for heat resistance and extended tool life in hard materials
• 135-degree split point reduces entry thrust and eliminates the need for a center punch on most surfaces
• Web-thinned, tapered web improves chip flow and lowers cutting resistance
• Screw machine length provides superior rigidity over jobber-length bits in production setups
• Straight-cylindrical shank fits standard drill chucks and collet holders without modification
• ANSI-compliant construction for dimensional consistency and interchangeability

Compatibility

Designed as a high-performance replacement or production drill bit for use in screw machines, drill presses, and CNC drilling applications requiring an 11/16 inch diameter cobalt bit with a straight-cylindrical shank, conforming to ANSI standards.

Installation Notes

This bit is installed and replaced by machinists or toolroom personnel. Ensure the machine spindle is fully stopped and locked out before changing tooling. Secure the shank firmly in the chuck or collet to the manufacturer-recommended engagement depth to prevent slippage under load. Apply appropriate cutting fluid for the workpiece material to manage heat buildup and extend tool life, particularly when drilling stainless or alloy steels.