Hertel 04138319 Cobalt Jobber Drill Bit Letter E

Product Description

The HERTEL 04138319 is a cobalt jobber-length drill bit sized to Letter E (0.2500 inches decimal equivalent), designed for heavy-duty holemaking in ferrous and hard metals. The 135-degree split point reduces walking at startup and lowers thrust required to initiate the cut. An oxide and TiN coating improves surface hardness and heat resistance across extended run times. The straight-cylindrical shank measures 1/4 inch in diameter, fitting standard drill chucks without adapters. This bit suits machinists, maintenance techs, and fabricators who need consistent hole quality in tough materials at a jobber length.

This drill bit is built for production and maintenance holemaking in steel, stainless, cast iron, and other hard-to-machine alloys where standard high-speed steel bits lose edge life quickly. The 4-inch overall length and 2-3/4-inch flute length position it as a standard jobber reach for through-holes and moderate-depth applications in both handheld and machine-spindle setups. Regular spiral geometry keeps chip evacuation predictable in most ferrous materials. Right-hand cutting direction is standard for conventional drill press, CNC, and hand-drill use.

Key Features

• Cobalt construction rated for heavy-duty service in hard and abrasive metals
• 135-degree split point reduces thrust and eliminates the need for a center punch on most surfaces
• Oxide and TiN dual coating improves wear resistance and surface hardness
• Web-thinned, tapered-web design lowers cutting resistance and extends tool life
• 1/4-inch straight-cylindrical shank fits standard three-jaw chucks without a reducer
• Regular spiral flute geometry promotes reliable chip clearing in ferrous materials

Compatibility

Designed as an OEM-style replacement or direct substitution for 1/4-inch (Letter E) jobber drill applications in standard drill press, CNC machining center, and hand-drill chucks that accept straight-cylindrical shanks.

Installation Notes

Installed by machinists, maintenance mechanics, and fabricators using standard drill press or CNC equipment. Secure the shank fully in the chuck and verify runout before engaging the workpiece. Use cutting fluid appropriate for the base material to manage heat when drilling stainless or alloy steels. Inspect the cutting edges and web area for wear before each use; a worn split point will increase thrust and reduce hole quality.