Hertel 04139242 Cobalt Jobber Drill No 77 135 Deg

Product Description

The HERTEL 04139242 is a cobalt jobber-length drill bit sized to wire gauge No. 77 (0.0180 inches decimal equivalent). It features a 135-degree split point that self-centers on contact, reducing walking on hard or slick surfaces. The oxide and TiN coating improves surface hardness and heat resistance for extended tool life in demanding holemaking applications. At 7/8 inches overall length with a 3/16-inch flute length, this is a compact bit built for tight-clearance or precision work. The straight-cylindrical shank seats securely in standard drill chucks. Installation and use are appropriate for machinists, tool-and-die professionals, and maintenance technicians working in metal fabrication, HVAC sheet metal, or general industrial environments.

This bit is designed for holemaking in metals including stainless steel, high-alloy steels, cast iron, and other hard-to-machine materials where cobalt grades outperform standard high-speed steel. The heavy-duty cobalt construction handles the elevated temperatures generated in interrupted cuts and hard materials. The regular spiral flute and right-hand cutting direction are standard for use in conventional drill presses, hand drills, and CNC machines. With an MOQ of 12 units per order, this bit is sourced as a shop consumable for production or service environments that cycle through small-diameter bits regularly.

Key Features

• Wire gauge No. 77 size — 0.0180 inches decimal equivalent for precision small-diameter holes
• 135-degree split point with web thinning reduces thrust and self-centers without a center punch
• Cobalt construction rated heavy duty for hard metals and high-heat cutting conditions
• Oxide and TiN dual coating extends wear life and resists heat buildup
• Regular spiral right-hand flute clears chips efficiently in through-hole and blind-hole applications
• Straight-cylindrical shank fits standard keyless and keyed drill chucks

Compatibility

Designed as a jobber-series replacement or consumable drill bit for use in standard drill chucks accepting a 0.0180-inch straight-cylindrical shank. Compatible with drill presses, hand drills, and CNC spindles set up for right-hand cutting tools in the applicable size range.

Installation Notes

Secure the shank fully in the chuck and verify runout before drilling. Use appropriate cutting fluid for the workpiece material to extend bit life and maintain hole quality. Wear eye protection and secure the workpiece — small-diameter cobalt bits are brittle under side-loading or flexing. Replace the bit when point geometry shows visible wear or when breakthrough burrs increase in size.