Hertel 4140208 Cobalt Jobber Drill Bit No.28 135 Deg

Product Description

The HERTEL 4140208 is a cobalt jobber-length drill bit with a TiAlN (titanium aluminum nitride) coating, designed for heavy-duty holemaking in demanding materials. Built to a wire gauge size of No.28 (0.1405 inches decimal), it features a 135-degree split point for self-centering entry and reduced thrust. The spiral flute geometry is regular-style with a web-thinned, tapered web configuration that improves chip evacuation and reduces walking on entry. Right-hand cutting direction. Overall length is 2-7/8 inches with a 1-3/4 inch flute length. The straight-cylindrical shank diameter matches the bit diameter at 0.1405 inches. This drill is suited for machinists, tool-and-die techs, and maintenance professionals working in production or job-shop environments.

The 4140208 falls in the Jobber series, the standard drill length most commonly used in drill presses, CNC machining centers, and hand-held power tools with standard chucks. Its cobalt construction and TiAlN coating make it appropriate for drilling stainless steel, hardened alloys, cast iron, and other abrasive or heat-generating workpiece materials where high-speed steel bits wear prematurely. The heavy-duty grade rating reflects its suitability for continuous or high-cycle production use rather than occasional light-duty applications.

Key Features

• Cobalt construction with TiAlN coating for heat resistance and extended tool life in hard or abrasive materials
• 135-degree split point reduces thrust and self-centers on entry without a center punch in many applications
• Web-thinned tapered web improves chip flow and lowers cutting resistance
• Regular spiral flute geometry compatible with standard drill press and CNC spindle feeds
• Straight-cylindrical shank at 0.1405 inches fits standard drill chucks without an adapter
• Heavy-duty grade rating for production and high-cycle holemaking

Compatibility

Designed as a jobber-series replacement or production-stock drill bit for any application requiring a No.28 wire gauge (0.1405 inch) hole. Fits standard drill chucks accepting a straight-cylindrical shank of 0.1405 inches.

Installation Notes

Install in a drill press, CNC machining center, or power drill with a properly tightened chuck before use. Secure the workpiece firmly before drilling to prevent rotation or movement. Use appropriate cutting fluid or coolant when drilling stainless steel or hardened alloys to manage heat, noting this bit does not support through-coolant. Inspect the cutting edges for wear or chipping before each use, as a damaged split point will affect hole quality and increase thrust load.