Precision Twist Drill 5999636 Reduced Shank Drill Bit

Product Description

The PRECISION TWIST DRILL 5999636 is a reduced shank twist drill bit designed for drilling into ferrous metals and a range of secondary materials including aluminum, copper, nickel, and titanium. The bit measures 15/16 inches (0.9375 inches) in diameter with a 1/2-inch Weldon flat shank, allowing it to seat securely in standard 1/2-inch chucks and holders without slippage under load. Overall length is 6 inches with a 3-inch spiral flute length, providing a maximum drilling depth of 3 inches. Constructed from high speed steel with a bright uncoated finish, this Series R57 bit is ground to a 118-degree standard point angle for general-purpose work. Right-hand cut with regular spiral flutes.

This drill bit is suited for production and maintenance drilling in ferrous metal stock including steel plate, structural shapes, and fabricated components. The reduced shank design allows a larger-diameter bit to run in a standard 1/2-inch capacity chuck or Weldon-style tool holder, expanding the range of a common setup without requiring a larger machine spindle. It also sees use in aluminum, copper, magnesium, and synthetic materials where a general-purpose HSS bit is appropriate. Machinists, tool-and-die technicians, fabricators, and maintenance mechanics are the typical installers.

Key Features

• 15/16-inch (0.9375-inch) cutting diameter with 1/2-inch reduced Weldon flat shank for use in standard 1/2-inch holders
• 118-degree standard point angle for general-purpose drilling in ferrous and non-ferrous materials
• 3-inch flute length supports drilling depths up to 3 inches with adequate chip clearance
• High speed steel construction provides good wear resistance across a broad range of workpiece materials
• Bright uncoated finish — compatible with cutting fluids and oils where required by the application
• Right-hand cut, regular spiral flutes, Series R57 — no coolant through-holes, external coolant only

Compatibility

Designed for use in 1/2-inch Weldon-style end mill holders and 1/2-inch capacity drill chucks. Suitable for ferrous metal as the primary workpiece material, with secondary compatibility for aluminum, cermet, copper, magnesium, nickel, synthetic, and titanium materials per Series R57 specifications. Conforms to ANSI standards.

Installation Notes

Secure the Weldon flat shank fully into the holder before tightening the set screw against the flat to prevent axial pull-out under cutting load. Ensure the drill press, lathe, or milling machine spindle is powered down and locked out before changing bits. Apply appropriate cutting fluid or oil when drilling ferrous metals to extend tool life and improve hole quality. Inspect the cutting edges and point for wear or chipping before each use.