Precision Twist Drill 5999681 Reduced Shank Drill Bit

Product Description

The PRECISION TWIST DRILL 5999681 is a reduced shank twist drill bit designed for general-purpose drilling in metal fabrication, maintenance, and machining applications. The bit measures 55/64 inches (0.8594 inches) in diameter with a 1/2-inch straight-cylindrical shank, allowing it to chuck into standard 1/2-inch drill chucks and presses without requiring a larger capacity spindle. Constructed from high speed steel with a bright, uncoated finish, it features a 118-degree standard point angle suited for drilling ferrous metals and a range of secondary materials. Overall length is 6 inches with a 3-inch flute length, providing adequate chip clearance in moderate-depth holes.

This bit is built for right-hand cutting with a regular spiral flute pattern and fits Series R56. It is appropriate for use on drill presses, magnetic drills, and hand-held power drills in industrial, shop, and field environments. Suitable primary workpiece material is ferrous metal. Secondary workpiece materials include aluminum, copper, magnesium, nickel, titanium, cermet, and synthetic materials. The reduced shank design is especially useful when drilling larger-diameter holes with equipment limited to a 1/2-inch chuck capacity.

Key Features

• 55/64-inch (0.8594-inch) drill diameter with 1/2-inch reduced straight-cylindrical shank for compatibility with standard 1/2-inch chucks
• 118-degree standard point angle for general-purpose entry on ferrous and non-ferrous metals
• High speed steel construction provides adequate hardness and heat resistance for typical shop drilling tasks
• Bright, uncoated finish — no additional coating to delaminate or obscure wear
• Regular spiral flute pattern promotes efficient chip evacuation up to 3 inches of flute length
• Right-hand cut, ANSI-standard geometry for predictable performance across common drill press setups

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for applications requiring a 55/64-inch hole diameter through equipment fitted with a 1/2-inch drill chuck. Conforms to ANSI standards.

Installation Notes

Installation and use of this drill bit should be performed by machinists, maintenance technicians, or other qualified trade professionals familiar with rotating cutting tools. Secure the reduced shank fully in the chuck and verify chuck key is removed before powering the drill or press. Wear appropriate eye protection and secure the workpiece before drilling. Do not exceed the rated speed range for the material being drilled, and allow adequate chip clearance to prevent bit binding or breakage.