Chicago-latrobe 50740 Extra Length Drill Bit 5/16 in Hss

Product Description

The CHICAGO-LATROBE 50740 is an extra length, high speed steel drill bit engineered for long reach drilling applications in cast iron and steel. It carries a 5/16 inch diameter with a 12 inch overall length and a 9 inch spiral flute, giving technicians and machinists the reach needed to bore through deep sections or confined structural members that standard-length bits cannot access. The 118-degree notched point and web-thinned, tapered web geometry reduce entry force and improve chip evacuation. An oxide finish adds mild corrosion resistance for shop and field storage. This is a Series 120X general purpose bit suited for professional drilling in metal fabrication, mechanical, and industrial maintenance trades.

The 50740 is designed for long reach applications where a standard jobber-length bit falls short. Typical use cases include drilling through structural steel, cast iron housings, deep flanges, and thick assemblies in manufacturing, maintenance, and mechanical contracting environments. The straight-cylindrical shank fits standard drill chucks without adapters. Right-hand cutting direction, regular spiral flute, and a two-flute configuration make this bit compatible with conventional corded or cordless drilling equipment running appropriate feeds and speeds for steel and cast iron stock.

Key Features

• 5/16 inch (0.3125 inch) diameter with diameter tolerance of +0.0000 to -0.0010 inches for precision fitment
• 12 inch overall length and 9 inch flute length for deep and long reach boring
• 118-degree notched point with web-thinned, tapered web for reduced thrust and improved starts
• High speed steel construction handles cast iron and steel cutting demands
• Oxide finish provides basic surface protection during storage and handling
• Straight-cylindrical shank at 0.3125 inch diameter fits standard three-jaw drill chucks directly

Compatibility

Designed as an OEM-style general purpose extra length drill bit for use in standard drill chucks accepting a 5/16 inch straight-cylindrical shank. Primary workpiece materials are cast iron and steel per manufacturer specification.

Installation Notes

Installation of this bit is performed by qualified machinists, mechanical contractors, or maintenance technicians using appropriate drilling equipment. Secure the straight-cylindrical shank firmly in a calibrated drill chuck before operation and confirm the workpiece is clamped or fixtured to prevent movement. Use cutting fluid or coolant appropriate for the workpiece material when drilling cast iron or steel to manage heat and extend bit life. Inspect the cutting edges for wear or chipping before each use and replace the bit if point geometry is compromised.