Hertel 66692435 Jobber Drill Bit Letter E Hss Tialn

Product Description

The HERTEL 66692435 is a Letter E jobber-length drill bit designed for general-purpose holemaking in metal and other hard materials. It features a 135-degree split point that reduces walking and requires no center punch on most surfaces. The TiAlN coating improves surface hardness and heat resistance, extending tool life in production drilling applications. The bit is manufactured from high speed steel and includes a web-thinned, tapered web configuration that lowers thrust and improves chip evacuation. With a 4-inch overall length and 2-3/4-inch flute length, it fits standard drill chucks and is appropriate for use in hand drills, drill presses, and CNC machines. Licensed machinists, tool-and-die workers, millwrights, and maintenance technicians are the typical end users.

This drill bit is suited for drilling through mild steel, aluminum, cast iron, and similar materials in both shop and field environments. The straight cylindrical shank accepts standard three-jaw drill chucks without modification. Its heavy-duty grade designation and NAS specification make it appropriate for aerospace and industrial maintenance applications where dimensional consistency and surface finish are important. The 0.2500-inch decimal diameter corresponds to a Letter E size, making it a common choice for tapping and reaming operations that require precise pre-drill sizing.

Key Features

• 135-degree split point reduces drill walking and lowers required feed pressure
• TiAlN coating increases surface hardness and thermal resistance for extended tool life
• Web-thinned tapered web reduces axial thrust and improves chip flow
• Regular spiral flute with right-hand cutting direction for standard drill press and hand drill use
• NAS specification designation for consistent dimensional tolerances
• Heavy-duty grade construction rated for production and repeat-cycle drilling

Compatibility

Designed as a standard Letter E jobber drill bit with a 0.2500-inch straight cylindrical shank, compatible with any three-jaw drill chuck accepting that shank diameter. Suitable for use in hand drills, benchtop drill presses, and CNC machining centers.

Installation Notes

Installation is performed by machinists or maintenance technicians using a standard drill chuck and key. Secure the shank fully in the chuck and verify concentricity before drilling. Ensure the workpiece is clamped or fixtured before engaging the bit to prevent rotation and injury. Follow applicable shop safety procedures including eye protection and appropriate feed rates for the material being drilled.