Chicago-latrobe 49427 Screw Machine Drill Bit 0.043 in

Product Description

The CHICAGO-LATROBE 49427 is a screw machine length drill bit designed for high-speed steel cutting in demanding shop and field applications. It carries a wire gauge size of 57 (0.0430 inches decimal) and features a 135-degree split point for accurate self-starting without a center punch. The two-flute spiral design with web thinning reduces thrust and promotes clean chip evacuation. At 1-3/8 inches overall length with a 1/2-inch flute length, this stub-length bit provides added rigidity compared to jobber-length bits, making it well-suited for close-tolerance drilling in tight spaces. It conforms to NAS 907 and ISO standards and is rated for heavy-duty tool performance.

This bit is intended for drilling cast iron and steel in production machining, maintenance, and repair environments. The screw machine (stub) length format reduces deflection and chatter when drilling small-diameter holes on drill presses, CNC machines, turret lathes, and manual mills. The straight-cylindrical shank fits standard drill chucks without adapters. Its coated high speed steel construction extends tool life when running at elevated speeds in ferrous materials. Machinists, tool and die workers, and industrial maintenance technicians are the primary installers and users of this bit.

Key Features

• Wire size 57 (0.0430 inches) with a tight diameter tolerance of +0.0000 to -0.0005 inches
• 135-degree split point for self-centering starts on ferrous materials
• Web-thinned parallel web reduces drilling thrust and heat buildup
• Screw machine (stub) length at 1-3/8 inches overall for maximum rigidity
• Coated high speed steel construction rated for heavy-duty tool performance
• Meets NAS 907 and ISO standards for dimensional and performance compliance

Compatibility

Designed as an OEM-style replacement or direct substitute for screw machine length drill bits in wire size 57 applications involving cast iron and steel workpieces. Fits any standard drill chuck accepting a straight-cylindrical shank at this diameter.

Installation Notes

This bit is installed and used by machinists and industrial maintenance technicians on drill presses, lathes, and milling machines. Secure the straight shank firmly in the chuck and verify runout before drilling. Use appropriate cutting fluid or coolant for ferrous materials to extend tool life, noting this bit does not support coolant-through delivery. Inspect the cutting edges before each use and replace the bit if chipping or excessive wear is observed.