Chicago-latrobe 50739 Extra Length Drill Bit 0.2969in Hss

Product Description

The CHICAGO-LATROBE 50739 is a high speed steel extra length drill bit designed for long-reach drilling applications where standard-length bits cannot reach. Built to Series 120X specifications, this bit features a 0.2969-inch diameter, a 12-inch overall length, and a 9-inch spiral flute for extended cutting reach. The oxide finish provides mild corrosion resistance and reduces chip welding during cutting. A notched point with web-thinned, tapered web geometry reduces thrust at entry and helps the bit self-center on the workpiece. This bit is suited for use by machinists, maintenance technicians, and trade professionals working in fabrication, HVAC equipment mounting, structural steel work, and similar trades requiring deep or obstructed hole drilling.

The 50739 is intended for long-reach drilling through cast iron and steel in situations where standard or jobber-length bits lack the reach. Typical applications include drilling through thick structural members, deep flanges, or confined mechanical assemblies. The straight-cylindrical shank seats in standard three-jaw chucks on drill presses, hand drills, and mill spindles without requiring special toolholding. Right-hand cutting direction is standard for conventional clockwise-rotation drilling equipment.

Key Features

• 12-inch overall length and 9-inch flute length for deep or long-reach drilling
• High speed steel construction handles steel and cast iron at conventional cutting speeds
• Oxide finish reduces friction and minor corrosion at the cutting zone
• 118-degree notched point with web thinning reduces entry thrust and improves self-centering
• Tapered web configuration adds rigidity along the extended flute length
• Straight-cylindrical shank fits standard three-jaw drill chucks without adapters
• Diameter tolerance of +0.0000 to -0.0010 inches for consistent hole sizing

Compatibility

Designed as a general-purpose extra length drill bit for use in standard three-jaw chucks on drill presses, hand drills, and milling machines. Primary workpiece materials are cast iron and steel per manufacturer specification.

Installation Notes

Installation and use of this bit should be performed by qualified machinists or trade professionals familiar with rotating cutting tools. Secure the straight-cylindrical shank firmly in a properly sized chuck before operation and verify runout before drilling. Always wear appropriate eye protection and secure the workpiece to prevent rotation. Reduce feed rate when drilling deep holes to allow chip evacuation and prevent bit deflection or breakage on extended-length tooling.