Precision Twist Drill 5999588 Reduced Shank Drill Bit

Product Description

The PRECISION TWIST DRILL 5999588 is a reduced shank twist drill bit designed for boring large-diameter holes in metalworking and general fabrication applications. The bit features a 1-3/8 inch cutting diameter with a reduced 1/2 inch Weldon shank, allowing it to be chucked in standard 1/2 inch drill presses, magnetic drills, and milling machines without requiring a larger spindle. Manufactured from high speed steel with a bright uncoated finish, it carries a 118-degree standard point angle suited for general-purpose drilling into ferrous and non-ferrous metals. Licensed tradespeople and machinists in HVAC, plumbing, electrical, and fabrication shops rely on this bit for punching clean, accurate holes in structural members and sheet metal assemblies.

This bit fits within the Series R57 product family and is rated for general-purpose use across a broad range of workpiece materials. Primary target material is ferrous metal, with secondary suitability for aluminum, copper, magnesium, nickel, titanium, and synthetic materials. The 3-inch flute length supports a maximum drilling depth of 3 inches, making it well suited for structural steel plate, angle iron, tube, and similar stock encountered in mechanical and electrical rough-in work. The Weldon shank with three flats prevents slippage under high torque loads common in large-diameter drilling operations.

Key Features

• 1-3/8 inch cutting diameter with a reduced 1/2 inch Weldon shank for compatibility with standard 1/2 inch chucks and collets
• 118-degree standard point angle for general-purpose drilling in ferrous and non-ferrous metals
• High speed steel construction provides adequate hardness and heat resistance for production drilling
• Three-flat Weldon shank design resists rotational slippage under high torque
• Bright uncoated finish — no coating degradation risk; suitable for use with cutting fluids
• Right-hand spiral flute, regular spiral, 3-inch flute length for chip evacuation up to 3 inches deep

Compatibility

Designed as a general-purpose reduced shank drill bit compatible with any 1/2 inch chuck or Weldon-style tool holder on drill presses, magnetic base drills, and milling machines. Rated for ferrous metal as the primary workpiece material, with secondary compatibility in aluminum, copper, magnesium, nickel, titanium, cermet, and synthetic materials per Series R57 specifications.

Installation Notes

Installation and use should be performed by a qualified machinist or tradesperson familiar with rotating cutting tools. Secure the Weldon shank fully into the tool holder and engage the set screw against a flat before operating. Always reduce spindle speed for larger-diameter bits and apply a suitable cutting fluid when drilling ferrous metals to extend tool life and maintain hole quality. Inspect the cutting edges and shank flats for wear or damage before each use.