Hertel 74131327 Drill Bit Letter U 135 Deg Cobalt

Product Description

The HERTEL 74131327 is a screw machine length drill bit sized to Letter U (0.3680 inches decimal equivalent), designed for high-production drilling in tough materials. Built from cobalt high-speed steel (HSCO), it handles harder workpiece materials and elevated cutting temperatures better than standard HSS bits. The 135-degree split point starts on contact without a center punch and reduces walking on flat or curved surfaces. A web-thinned parallel web keeps thrust loads manageable. At 3.125 inches overall length, the stub-length geometry provides rigidity in drill press, lathe, and CNC turret applications. Licensed trade professionals and machinist-grade technicians are the primary users.

This bit fits production and maintenance drilling scenarios where a short, stiff drill is preferred over jobber length. Typical applications include through-hole and blind-hole drilling in steel, stainless, cast iron, and other ferrous alloys. The straight cylindrical shank seats directly in standard drill chucks, collet holders, and quick-change tool systems. It cuts right-hand, making it compatible with conventional spindle rotation on virtually all drill presses and machining centers. The 1.8125-inch flute length accommodates moderate-depth holes within the screw machine length range.

Key Features

• Cobalt (HSCO) construction for heat resistance and extended tool life in ferrous materials
• 135-degree split point for self-centering starts and reduced thrust
• Web-thinned parallel web lowers axial cutting force
• Stub screw machine length (3.125 inches OAL) maximizes rigidity and minimizes deflection
• Straight cylindrical shank fits standard drill chucks and collet systems
• Regular spiral flute with right-hand cutting direction for standard spindle rotation

Compatibility

Designed as a direct-fit screw machine length drill bit for use in drill presses, CNC turrets, lathes, and hand-held drill drivers accepting a straight cylindrical shank in the 0.3500 to 0.4000 inch decimal inch size range.

Installation Notes

Secure the shank fully in the chuck or collet before engaging the spindle, and verify runout with a dial indicator when tight tolerances are required. Follow standard machine guarding and PPE requirements per OSHA 29 CFR 1910 Subpart O during setup and operation. Use an appropriate cutting fluid or coolant for the workpiece material to extend tool life, noting this bit does not support through-coolant delivery. Inspect the split point and cutting edges for wear or chipping before each use and replace if edge integrity is compromised.