Precision Twist Drill 5998571 7/16 Inch Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5998571 is a screw machine length drill bit designed for high-performance drilling in demanding shop and field environments. Built from high speed steel with a bright uncoated finish, this bit measures 7/16 inch (0.4375 inches) in diameter and features a 118-degree standard point angle with web thinning for easier penetration and reduced thrust. The straight-cylindrical shank fits standard drill chucks without modification. At 3-7/16 inches overall length, the shortened screw machine geometry provides greater rigidity than jobber-length bits, making it well suited for drill press, CNC, and turret lathe applications where chatter and deflection must be minimized.

This Series R40 bit is rated for general purpose use with a high-performance designation, covering a drill size range of 0.4000 to 0.4500 inches. The primary workpiece material listed is titanium, though the high speed steel construction also handles steel, aluminum, cast iron, and plastics in typical production and maintenance environments. The 2-1/16 inch flute length provides a 2.5xD flute-to-diameter ratio, allowing adequate chip evacuation in short-depth holes. It is installed and used by machinists, tool and die technicians, HVAC fabricators, plumbers, and electricians who require consistent, repeatable hole sizing.

Key Features

• 7/16 inch (0.4375 inches) diameter, screw machine length for added rigidity
• 118-degree standard point angle with web thinning and tapered web configuration
• High speed steel construction, bright uncoated finish — no coating buildup to affect tolerance
• Right-hand cut, regular spiral flute for positive chip removal
• Straight-cylindrical shank fits standard 3-jaw and keyed chucks
• Meets ANSI standards; Series R40 general purpose grade

Compatibility

Designed as a screw machine length replacement bit fitting any standard drill chuck accepting a straight-cylindrical shank in the 7/16 inch size range, conforming to ANSI specification.

Installation Notes

Secure the shank fully in the chuck before operation and verify chuck key removal. Power down or de-energize the drill press, lathe, or hand drill completely before changing bits. Use appropriate cutting fluid or coolant when drilling titanium or hardened steel to extend tool life and prevent work hardening. Dispose of worn bits per shop safety protocols — edges remain sharp after tool failure.