Hertel 66691759 Cobalt Screw Machine Drill Bit Letter Z

Product Description

The HERTEL 66691759 is a cobalt screw machine length drill bit sized to Letter Z (0.4130 inches decimal equivalent), designed for high-productivity drilling in tough materials including alloy steels, stainless steels, and hard exotics. The bit features a TiN (titanium nitride) coating that extends tool life by reducing friction and heat buildup at the cutting edge. At 3-3/8 inches overall length with a 2-inch flute, this stub-length geometry provides rigidity and reduces deflection in production drilling applications. The 135-degree split point starts on contact without a center punch, and the web-thinned construction lowers thrust requirements. Licensed trades and production machinists install this bit in CNC equipment, drill presses, and hand-held power tools.

This bit is suited for use in metal fabrication shops, maintenance and repair operations, and general manufacturing environments where Letter Z sizing is required for tapping or close-tolerance hole preparation. The straight cylindrical shank fits standard drill chucks. The heavy-duty cobalt grade handles interrupted cuts and abrasive materials that would rapidly wear standard high-speed steel tooling. Right-hand cutting direction is standard for conventional drilling setups. The Series HSCO135-TN designation identifies this as part of a cobalt, 135-degree point, TiN-coated product family.

Key Features

• Letter Z size at 0.4130 inches decimal equivalent for precise hole sizing
• Cobalt construction rated heavy duty for hard and abrasive metals
• TiN coating reduces friction and extends cutting edge life
• 135-degree split point starts on contact, no center punch required
• Web-thinned parallel web reduces drilling thrust
• Screw machine (stub) length at 3-3/8 inches OAL for maximum rigidity
• Regular spiral flute with right-hand cutting direction

Compatibility

Designed as an OEM-style replacement or direct-use cutting tool compatible with any drill press, CNC machining center, or power drill accepting a 0.4130-inch straight cylindrical shank. Suitable for standard three-jaw drill chucks in that bore range.

Installation Notes

Install this bit into a properly rated drill press, mill, or hand-held drill with a chuck rated for the shank diameter. Ensure the workpiece is secured before drilling. Use appropriate cutting fluid for the material being drilled to further extend tool life, even though coolant-through is not supported on this bit. Inspect the cutting edge before each use and replace the bit if chipping or excessive wear is observed.