Chicago-latrobe 49430 Screw Machine Drill Bit 0.04 in

Product Description

The CHICAGO-LATROBE 49430 is a screw machine length drill bit designed for high-precision drilling in metalworking applications. Built from high-speed steel with a coated finish, this bit features a 135-degree split point that reduces walking and allows fast penetration without a center punch. The web-thinned, parallel-web construction lowers cutting resistance and improves chip evacuation. At 0.04 inches in diameter (Wire Size 60), this is a small-diameter heavy-duty bit suited for production drilling in tight or restricted-clearance setups. Machinists, tool-and-die shops, and precision fabricators rely on this series for consistent hole quality in cast iron and steel.

The 49430 is rated for primary use in cast iron and steel workpieces. Its screw machine length body, measuring 1-3/8 inches overall with a 1/2-inch flute length, fits standard drill presses, CNC machining centers, screw machines, and hand-held drilling equipment where stub-length bits are preferred for rigidity and reduced deflection. The straight-cylindrical shank provides a secure grip in standard three-jaw chucks and collets. This bit is manufactured to NAS 907 and ISO standards, making it appropriate for aerospace and precision industrial environments.

Key Features

• Wire Size 60 (0.04 inches) diameter with a tight tolerance of +0.0000 to -0.0005 inches
• 135-degree split point reduces thrust force and eliminates center-punch requirement
• Web-thinned, parallel-web design improves chip flow and lowers cutting torque
• High-speed steel construction with coated finish for extended tool life in ferrous materials
• Screw machine (stub) length for maximum rigidity and minimal deflection in small-diameter drilling
• Meets NAS 907 and ISO specifications for precision and aerospace-grade applications

Compatibility

Designed for drilling cast iron and steel workpieces. Fits standard three-jaw chucks and collets accepting a straight-cylindrical shank at 0.04 inches diameter. Compatible with drill presses, screw machines, CNC machining centers, and handheld drilling equipment.

Installation Notes

Install and operate this bit per standard machining practices for small-diameter high-speed steel tooling. Power down and lock out the machine before changing bits or adjusting the chuck. Use appropriate cutting fluid or lubricant when drilling steel to reduce heat buildup and extend bit life. At 0.04 inches diameter, apply light, consistent feed pressure to avoid bit breakage — excessive force is the primary cause of failure at this size range.