Chicago-latrobe 48249 Screw Machine Drill Bit 0.339 in Hss

Product Description

The CHICAGO-LATROBE 48249 is a screw machine length drill bit designed for high-productivity drilling in cast iron and steel. Built from high speed steel with a coated finish, it features a 135-degree split point and web-thinned geometry that reduces thrust and improves hole entry accuracy. The straight-cylindrical shank fits standard drill chucks without modification. At 3 inches overall length, the screw machine format provides added rigidity compared to jobber-length bits, making it well suited for production drilling and CNC or turret applications where runout and deflection must be minimized. This is a heavy-duty series bit appropriate for use by machinists and trade professionals working in metal fabrication and mechanical service environments.

The 48249 is rated for primary workpiece materials of cast iron and steel. Its short, rigid body makes it a common choice for screw machine operations, drill press work, and CNC machining centers where a standard jobber bit would introduce too much flex. The Series 2159 designation places it within a heavy-duty production line. The 2-flute spiral design with regular spiral type promotes consistent chip evacuation during through-hole and blind-hole drilling in ferrous metals. Diameter tolerance is held to +0.0000 to -0.0010 inches, supporting close-tolerance work to NAS 907 specification.

Key Features

• 135-degree split point reduces entry thrust and self-centers on contact
• Web-thinned, parallel web configuration lowers cutting resistance in ferrous materials
• High speed steel construction with coated finish for extended tool life
• Screw machine length body provides rigidity and reduces deflection
• Diameter tolerance of +0.0000 to -0.0010 inches for close-tolerance holes
• Meets NAS 907 and ISO standards for production-grade tooling

Compatibility

Designed for drilling cast iron and steel. Straight-cylindrical shank is compatible with standard drill chucks used on drill presses, screw machines, and CNC machining centers. Rated for workpiece materials within the 0.3000 to 0.3500 inch drill bit size range.

Installation Notes

Install and replace drill bits only while the machine spindle is fully stopped and locked out per applicable machine safety procedures. Ensure the chuck or collet is clean and free of chips before seating the shank to maintain concentricity. Inspect the cutting edges and point before each use and discard bits showing chipping or excessive wear to avoid workpiece damage or bit breakage. Coolant-through is not supported on this bit; apply cutting fluid externally when drilling in steel at higher feed rates.