Chicago-latrobe 49018 Screw Machine Drill Bit 8 Mm Cobalt

Product Description

The CHICAGO-LATROBE 49018 is a screw machine length cobalt drill bit designed for high-production drilling in cast iron and steel. The shortened flute length reduces deflection and increases rigidity compared to jobber-length bits, making it well suited for CNC machining centers, turret lathes, and screw machine operations where stub-length tooling is required. The 135-degree split point starts on contact without a center punch and reduces thrust load. At 8 mm (0.3150 inches) diameter and 3.224 inches overall length, the bit carries a cobalt M42 high-speed steel construction with an oxide coating for heat and wear resistance.

This bit is intended for professional machining environments where tight tolerances and consistent hole quality in ferrous materials are required. Primary workpiece materials include cast iron and steel. The straight-cylindrical shank accepts standard drill chucks and collet systems. With a 4xD flute-to-diameter ratio and a maximum drilling depth of 1.1025 inches, this bit is optimized for shallow, high-speed production drilling rather than deep-hole applications. It is appropriate for machine shops, maintenance facilities, and fabrication environments.

Key Features

• M42 cobalt construction for heat resistance in ferrous materials
• 135-degree split point for self-centering start and reduced thrust
• Screw machine (stub) length increases rigidity and reduces deflection
• Oxide coating improves surface hardness and heat dissipation
• Right-hand cut with regular spiral flutes for efficient chip evacuation
• Diameter tolerance of +0.0000 to -0.0010 inches for consistent hole sizing

Compatibility

Designed for use in standard drill chucks and collet systems accepting an 8 mm straight-cylindrical shank. Rated for cast iron and steel workpiece materials. Conforms to DIN 1897 specification for screw machine length twist drills.

Installation Notes

Install and remove this bit with the machine fully stopped and the spindle locked. Ensure the chuck or collet is clean and undamaged before seating the straight shank to maintain concentricity. Use appropriate cutting fluid or coolant when drilling steel to extend tool life, noting this bit does not support through-coolant. Replace the bit if runout or diameter tolerance is no longer within acceptable range for the application.