Hertel 04139424 Cobalt Jobber Drill Bit Letter O

Product Description

The HERTEL 04139424 is a cobalt jobber-length drill bit sized at Letter O (0.3160 inches) with a 135-degree split point and an oxide and TiN coating. Built for heavy-duty holemaking, this bit delivers increased heat and wear resistance compared to standard high-speed steel tooling. The split point geometry reduces walking at entry and requires less thrust, making it well-suited for harder or tougher workpiece materials. The overall length is 4.5 inches with a flute length of 3.1875 inches. Right-hand cutting with a regular spiral and straight-cylindrical shank rounds out the design for compatibility with standard drill chucks.

This drill bit is intended for general holemaking applications in metalworking, fabrication, and maintenance environments. The cobalt construction and heavy-duty grade make it appropriate for harder steels, stainless, and other alloys where standard tooling wears prematurely. Typical users include machinists, maintenance technicians, metal fabricators, and industrial tradespeople who require consistent performance across repeated use cycles. Sold individually as a single unit.

Key Features

• Cobalt construction with oxide and TiN coating for extended tool life in hard and abrasive materials
• 135-degree split point reduces drill walking and lowers required feed pressure
• Web-thinned, tapered web design improves chip evacuation and cutting efficiency
• Regular spiral flute with right-hand cutting direction for standard drilling operations
• Straight-cylindrical shank fits standard three-jaw drill chucks without adapters
• Heavy-duty grade rating suited for demanding production or maintenance use

Compatibility

Designed as a jobber-length drill bit for use in standard drill chucks accepting a 0.3160-inch straight-cylindrical shank, compatible with drill presses, hand drills, and CNC drilling setups configured for jobber-series tooling.

Installation Notes

Secure the shank fully in the drill chuck and verify runout before beginning operation. Use appropriate cutting fluid or coolant when drilling hard alloys to extend tool life, noting this bit does not support through-coolant delivery. Ensure the workpiece is clamped securely before starting the cut. Inspect the cutting edges for wear regularly, as cobalt bits can be reground when properly equipped.