Hertel 4139630 Cobalt Jobber Drill Bit 3/16 Inch

Product Description

The HERTEL 4139630 is a cobalt jobber-length drill bit with a TiAlN (titanium aluminum nitride) coating, designed for heavy-duty holemaking in demanding materials. The 135-degree split point reduces walking on entry and lowers the thrust required to start the cut, making it well-suited for hard steels, stainless, and other tough alloys. The straight-cylindrical shank measures 3/16 inch in diameter, and the overall length is 3.5 inches with a flute length of 2.3125 inches. A spiral, regular-helix flute geometry evacuates chips efficiently during through-hole and blind-hole operations. This bit is intended for use by machinists, tool-and-die tradespeople, HVAC sheet-metal workers, and other trade professionals who drill frequently into hard or abrasive materials.

This drill bit is sized at 3/16 inch (0.1875 inch decimal), placing it within the 0.1500 to 0.2000 inch heavy-duty size range. It is appropriate for use in ferrous metals, hardened steels, cast iron, and other materials that would wear out standard high-speed steel bits quickly. The right-hand cutting direction and web-thinned, tapered web configuration reduce cutting torque at the tip. The TiAlN coating adds surface hardness and heat resistance, extending tool life in dry or semi-dry cutting applications. Typical installation environments include machine shops, fabrication floors, and field service situations requiring reliable performance in hard materials.

Key Features

• Cobalt steel construction for high heat resistance and durability in hard materials
• TiAlN coating increases surface hardness and extends tool life in abrasive applications
• 135-degree split point reduces drill walking and cutting thrust on entry
• Web-thinned, tapered web lowers torque demand at the drill tip
• Right-hand spiral flute promotes efficient chip evacuation
• Straight-cylindrical shank fits standard three-jaw chucks and drill presses without adapters

Compatibility

Designed as a jobber-series replacement or stock drill bit for use in standard three-jaw chucks, drill presses, and hand drills accepting a 3/16 inch straight-cylindrical shank. Fits within the UNSPSC category 23241634 for twist drill bits.

Installation Notes

Secure the shank fully in the chuck before operation and confirm the chuck key is removed before powering the drill. When drilling hard or thick stock, use appropriate cutting fluid or coolant to manage heat buildup unless operating in a dry-rated application where the TiAlN coating is sufficient. Ensure workpiece is clamped securely to prevent movement during drilling. Inspect the cutting edges for wear before each use, as cobalt bits used dry in abrasive materials can show tip wear that is not always visible without magnification.