Precision Twist Drill 5999659 Reduced Shank Drill Bit

Product Description

The PRECISION TWIST DRILL 5999659 is a reduced shank twist drill bit designed for general-purpose hole drilling in ferrous metals, aluminum, copper, titanium, nickel, magnesium, and synthetic materials. The bit measures 27/32 inch (0.8438 inch decimal) in cutting diameter with a 1/2 inch Weldon shank that seats securely in standard drill chucks and holders equipped for flat-drive retention. Built from high speed steel with a bright uncoated finish, it delivers reliable performance across a wide range of shop and field drilling applications. The 118-degree standard point angle suits most common workpiece materials without requiring specialized point geometry.

This drill bit is well suited for use in drill presses, CNC knee mills, and manual milling machines where a reduced shank allows a larger cutting diameter to be chucked in a standard 1/2 inch capacity holder. The 3-inch flute length and 6-inch overall length make it practical for moderate-depth holes in structural steel, plate, aluminum extrusions, and similar materials. The three-flat Weldon shank prevents slipping under torque, which is important when cutting larger diameters in harder ferrous stock. Series R57 positions this as a general-purpose production bit appropriate for maintenance shops, fabrication, and light manufacturing environments.

Key Features

• 27/32 inch cutting diameter (0.8438 inch decimal) with a 1/2 inch Weldon shank for reduced-shank chuck compatibility
• 118-degree standard point angle for general-purpose drilling across ferrous and non-ferrous materials
• High speed steel construction provides toughness and heat resistance in production drilling
• Three-flat Weldon shank resists rotational slipping under high torque loads
• 3-inch flute length supports a maximum drilling depth of 3 inches
• Bright uncoated finish; no coating delamination concern in interrupted cuts or re-sharpening
• Right-hand cut with regular spiral flutes for standard chip evacuation

Compatibility

Designed as a general-purpose reduced shank drill bit compatible with 1/2 inch capacity drill chucks, Weldon-style end mill holders, and set-screw-style drill holders used on drill presses, knee mills, and CNC machining centers. Rated for use in ferrous metals, aluminum, copper, magnesium, nickel, titanium, cermet, and synthetic materials per Series R57 specifications.

Installation Notes

A licensed machinist or qualified maintenance technician should secure the Weldon shank fully into the holder before tightening all set screws against the flats to prevent axial pullout under load. Power down and lock out the machine before installing or changing the bit. Confirm runout with a dial indicator before drilling finished or close-tolerance holes. No coolant is specified for this bit; follow shop standard dry-cutting or mist-cooling practices appropriate to the workpiece material.