Hertel 74131343 Cobalt Drill Bit Letter W 135 Deg

Product Description

The HERTEL 74131343 is a cobalt screw machine length drill bit sized to Letter W (0.386 inches decimal) with a 135-degree split point. Designed for shorter reach and rigid setups, screw machine length bits reduce deflection and improve hole accuracy in production and maintenance drilling. The split point geometry starts on contact without a center punch, and the web-thinned design reduces thrust load. Two regular spiral flutes clear chips efficiently while the straw finish indicates heat treatment consistent with high-speed cobalt steel. A straight cylindrical shank fits standard drill chucks. This bit is suited for drilling ferrous metals, stainless steel, cast iron, and other hard materials where standard HSS bits wear prematurely.

This drill bit fits production machining, maintenance, and repair operations in industrial, mechanical, and trade environments. The screw machine length body keeps the cutting edge close to the chuck for stability in drill presses, CNC machines, and hand-held drilling equipment. It is well-suited for applications requiring consistent hole size in the 0.35 to 0.40 inch range on hard or abrasive workpieces. Machinists, millwrights, and maintenance technicians working in metal fabrication, HVAC equipment manufacturing, and mechanical service use this bit type routinely.

Key Features

• Letter W size: 0.386 inches decimal, within the 0.35 to 0.40 inch bit size range
• 135-degree split point starts on contact without center punching and reduces walking
• Web-thinned parallel web lowers axial thrust for cleaner entry in hard materials
• Cobalt construction resists heat and abrasion, outlasting standard HSS in ferrous and stainless applications
• Screw machine (stub) length minimizes deflection for tighter hole tolerances
• Right-hand cutting, regular spiral flutes, straight shank - compatible with standard drill chucks

Compatibility

Designed as a direct-fit screw machine length drill bit for use in drill presses, CNC drill heads, and hand-held drilling equipment accepting a straight cylindrical shank. Fits applications requiring a Letter W or 0.386-inch hole diameter.

Installation Notes

Secure the straight shank fully in the chuck and verify chuck key is removed before starting the spindle. Use appropriate cutting fluid or coolant when drilling stainless steel or hardened ferrous metals to extend bit life and improve surface finish. Reduce feed pressure when breaking through to avoid grab. Inspect the split point for chipping after heavy use - a damaged point will cause runout and oversized holes.