Hertel 74131269 Letter O Cobalt Drill Bit 135 Deg

Product Description

The HERTEL 74131269 is a screw machine length cobalt drill bit in Letter O size (0.3160 inches decimal equivalent), designed for high-speed drilling in tough materials including stainless steel, heat-treated alloys, and hardened steels. The 135-degree split point reduces walking and lowers the thrust needed to start a hole without a center punch. Web thinning further reduces cutting resistance at the tip. At 2-15/16 inches overall length, the screw machine format gives rigidity in short-reach applications such as drill press work, CNC turrets, and hand-held drilling in tight spaces. Machinists, tool-and-die workers, and maintenance mechanics are the primary users.

This bit suits production and job-shop environments where shorter flute length and maximum rigidity matter more than deep-hole reach. The straight cylindrical shank fits standard drill chucks without adapters. Regular spiral flutes with a parallel web configuration evacuate chips cleanly in both ferrous and non-ferrous materials. Typical applications include tapping prep holes, through-hole drilling in structural steel, and general metalworking operations where cobalt grade tooling is specified for heat resistance and edge retention at elevated cutting speeds.

Key Features

• Letter O size - 0.3160 inches decimal equivalent, within the 0.3000 to 0.3500 inch size range
• 135-degree split point for self-centering starts and reduced thrust requirements
• Cobalt (HSS-Co) tool material for heat resistance in hard and abrasive metals
• Web-thinned parallel web configuration reduces cutting resistance at the tip
• Screw machine length (2-15/16 inches OAL) provides rigidity for short-reach drilling
• Right-hand cutting with regular spiral flutes for efficient chip evacuation
• Straight cylindrical shank fits standard drill chucks without special adapters

Compatibility

Designed as an OEM-style replacement or direct substitute for Letter O screw machine length cobalt drill bits in any standard drill chuck accepting a straight cylindrical shank. Part of the HSCO135 series.

Installation Notes

Installation is performed by machinists, toolroom technicians, or maintenance mechanics. Secure the shank fully into the drill chuck and verify runout before beginning a cut. When drilling hard alloys, use appropriate cutting fluid to extend tool life and manage heat buildup. Do not exceed the recommended surface footage for cobalt tooling in the material being drilled, and never reverse-run a spiral-flute bit to clear chips.