Chicago-latrobe 48421 Screw Machine Drill Bit 0.067 in

Product Description

The CHICAGO-LATROBE 48421 is a screw machine length drill bit designed for high-production and close-tolerance drilling in ferrous materials. Built from high speed steel with a coated finish, it carries a 135-degree split point angle that reduces walking and lowers thrust on entry. The web-thinned, parallel-web construction supports clean starts without a center punch. At 0.067 inches (Wire Size 51) in diameter, it is sized for tight-clearance fastener and pilot-hole work. Overall length is 1-11/16 inches, making it well-suited to drill press, CNC, and screw machine applications where a stub-length tool improves rigidity and reduces deflection. Licensed machinists, tool-and-die techs, and industrial maintenance professionals are the primary users.

This bit is intended for drilling cast iron and steel in production and maintenance environments. The short screw machine length provides added stiffness over jobber-length bits, which matters in high-cycle drilling on automatic screw machines, CNC lathes, and turret-style drill presses. The spiral flute geometry and right-hand cut are standard for conventional drilling operations. It conforms to NAS 907 and ISO standards, making it appropriate for aerospace and precision industrial work where dimensional consistency and tolerance documentation are required. Diameter tolerance is held to +0.0000 to -0.0005 inches.

Key Features

• 135-degree split point reduces thrust and eliminates walking on entry
• Web-thinned, parallel-web design improves chip evacuation and cutting efficiency
• High speed steel with coated finish for extended tool life in steel and cast iron
• Screw machine (stub) length improves rigidity and reduces deflection in tight setups
• Straight-cylindrical shank fits standard 3-jaw and keyless drill chucks
• Meets NAS 907 and ISO standards for use in tolerance-critical applications

Compatibility

Designed as an OEM-style replacement and production drill bit for use in standard straight-shank drill chucks on drill presses, CNC machining centers, turret lathes, and automatic screw machines. Primary workpiece materials are cast iron and steel.

Installation Notes

Installation and use should be performed by qualified machinists or tool-and-die professionals familiar with cutting tool setup and speeds-and-feeds selection. Secure the shank fully in the chuck before operation and verify runout before high-cycle use. Always reduce spindle speed and feed rate when drilling into hardened or abrasive steel grades. Inspect the cutting edges and split point for wear at regular intervals, as a worn point on a small-diameter bit can cause breakage and workpiece damage.