Hertel 04138558 Cobalt Jobber Drill Bit No. 8 135 Deg

Product Description

The HERTEL 04138558 is a No. 8 wire-size cobalt jobber drill bit designed for heavy-duty holemaking in tough materials. Built from cobalt high-speed steel with an oxide and TiN coating, it delivers extended tool life and heat resistance in demanding applications. The 135-degree split point reduces thrust and self-centers on the workpiece without a center punch. The web-thinned, tapered-web construction reduces cutting resistance. At 3.625 inches overall length with a 2.4375-inch flute length, this right-hand spiral-flute bit fits standard drill chucks via its straight-cylindrical shank. The decimal diameter is 0.1990 inches. Licensed tradespeople and machinists use this bit for production drilling and maintenance work.

This jobber-length drill is suited for holemaking in ferrous metals, stainless steel, cast iron, and other hard or abrasive materials where standard high-speed steel bits underperform. The cobalt alloy content and heavy-duty grade designation make it a practical choice for shop environments, fabrication work, and field service where bit longevity matters. It fits into standard drill presses, handheld power drills, and CNC-style drill setups that accept a 0.1990-inch straight shank. Single-piece packaging makes it straightforward to stock individually or add to a kit.

Key Features

• Cobalt high-speed steel construction with oxide and TiN coating for heat resistance and extended tool life
• 135-degree split point for reduced thrust and self-centering without a pilot hole
• Web-thinned tapered web reduces cutting resistance during entry
• Right-hand regular spiral flute for efficient chip evacuation
• Straight-cylindrical shank fits standard drill chucks — no adapter needed
• Heavy-duty grade rated for drilling hard and abrasive ferrous materials

Compatibility

Designed as a jobber-series replacement or addition for applications requiring a No. 8 wire-size (0.1990-inch) straight-shank drill bit; compatible with any drill press, handheld power drill, or CNC spindle that accepts a 0.1990-inch straight-cylindrical shank.

Installation Notes

This bit is installed and replaced by machinists, millwrights, and maintenance technicians using standard drill chucks or collet systems. Secure the shank fully in the chuck before operation and verify chuck key is removed before starting the drill. Use appropriate cutting fluid or coolant when drilling hard ferrous metals to preserve coating life, even though coolant-through is not supported by this bit. Follow applicable shop safety standards and personal protective equipment requirements when operating drilling equipment.