Chicago-latrobe 49399 Screw Machine Drill Bit 0.136 in

Product Description

The CHICAGO-LATROBE 49399 is a screw machine length drill bit designed for high-production drilling in cast iron and steel. Built from high speed steel with a coated finish, it carries a 135-degree split point that reduces walking and improves bite on hard surfaces. The web-thinned, parallel-web construction lowers thrust requirements and extends tool life under heavy-duty cycling. At 0.136 inches (Wire Size 29) in diameter with an overall length of 1-15/16 inches, this stub-length bit offers increased rigidity compared to jobber-length equivalents. It is sized for machinists, tool-and-die shops, and maintenance mechanics running screw machines or CNC drilling operations.

This bit is intended for use in metal-cutting applications involving cast iron and steel workpieces. The screw machine length format is a common choice in production environments where shorter flute length and tighter tolerances are required at the spindle. The right-hand spiral flute clears chips efficiently during through-hole drilling. It meets NAS 907 and ISO standards, making it suitable for aerospace, industrial, and general precision machining environments where specification compliance is required.

Key Features

• Wire Size 29 diameter (0.1360 inches) with a tight tolerance of +0.0000 to -0.0007 inches
• 135-degree split point reduces drill walk and improves penetration on hard metals
• Web-thinned, parallel-web construction lowers axial thrust in heavy-duty drilling
• High speed steel construction with coated finish for wear resistance
• Screw machine (stub) length at 1-15/16 inches overall increases rigidity at the spindle
• Meets NAS 907 and ISO specifications for use in compliance-driven applications

Compatibility

Designed as a heavy-duty OEM-style replacement or production-use drill bit for screw machines and CNC drilling equipment working with cast iron and steel workpieces. Fits standard straight-cylindrical shank chucks and collets accepting 0.136-inch shank diameter tooling.

Installation Notes

This bit is installed by machinists and maintenance mechanics in drill press, screw machine, or CNC spindle applications. Ensure the machine is fully powered down and the spindle is locked before changing tooling. Secure the straight-cylindrical shank fully in the chuck or collet to the rated grip depth before operation. Do not exceed the rated feed and speed for high speed steel tooling when drilling hardened steel or cast iron.