Hertel 74131251 Screw Machine Drill Bit Letter N Cobalt

Product Description

The HERTEL 74131251 is a cobalt screw machine length drill bit sized to Letter N (0.3020 inches decimal equivalent) with a 135-degree split point and web-thinned geometry. Screw machine length bits are shorter than jobber length, which improves rigidity and reduces deflection in close-tolerance drilling applications. The split point geometry allows the bit to self-center on contact, eliminating the need for a center punch on most materials. Two regular spiral flutes provide efficient chip evacuation during through-hole and blind-hole work. This bit is used by machinists, tool-and-die techs, and maintenance professionals who need consistent, accurate holes in ferrous metals and stainless steel.

Screw machine length cobalt bits are a standard choice in production environments, CNC machining centers, drill presses, and manual machine tools where heat buildup from hard or abrasive materials would degrade high-speed steel tooling. The shorter overall length of 2.8125 inches keeps the bit seated firmly in the chuck and reduces runout when drilling through steel, cast iron, stainless, and similar materials. The straight cylindrical shank is compatible with standard three-jaw drill chucks and collet-style tool holders across a wide range of machine spindles.

Key Features

• Letter N size: 0.3020 inch decimal equivalent for precision fitment applications
• 135-degree split point with web thinning for self-centering and reduced thrust force
• Cobalt construction for heat resistance when drilling hard ferrous and stainless materials
• Screw machine (stub) length improves rigidity and reduces deflection versus jobber length
• Right-hand cut with regular spiral flutes for standard chip evacuation
• Straight cylindrical shank fits standard drill chucks and collet holders

Compatibility

Designed as a direct-fit replacement or stock bit for standard three-jaw drill chucks and collet-style tool holders accepting a straight cylindrical shank in the 0.3000 to 0.3500 inch drill bit size range.

Installation Notes

This bit is installed and serviced by machinists and maintenance technicians. Ensure the machine spindle is fully powered down and locked out before changing tooling. Seat the shank fully and evenly in the chuck or collet before tightening to prevent runout. Use appropriate cutting fluid for the workpiece material to extend tool life when drilling hard metals.