Hertel 66691379 5/16 Inch Cobalt Drill Bit 135 Deg

Product Description

The HERTEL 66691379 is a screw machine length drill bit designed for high-performance drilling in metal and hard materials. Built from cobalt steel with a titanium nitride (TiN) coating, it delivers extended tool life and heat resistance under demanding conditions. The 135-degree split point reduces walking and allows the bit to self-center without a pilot hole. At 2-13/16 inches overall length with a 5/16-inch diameter, this is a stub-length format optimized for rigidity and minimal deflection. Machinists, tool-and-die workers, and maintenance technicians reach for this bit when drilling steel, stainless, cast iron, and other abrasive alloys.

This bit fits standard drill chucks and CNC machine spindles accepting a straight cylindrical shank with a 0.3125-inch shank diameter. Its compact screw machine length makes it well suited for drill presses, turret lathes, machining centers, and hand drill applications where clearance is limited and hole accuracy matters. The regular spiral flute and web-thinned, parallel web construction promote chip evacuation and reduce thrust in production drilling environments.

Key Features

• Cobalt steel construction for elevated heat and wear resistance in hard-metal drilling
• TiN coating extends cutting edge life and reduces friction at the tool-workpiece interface
• 135-degree split point with web thinning for self-centering entry and reduced thrust
• Screw machine (stub) length at 2-13/16 inches overall for maximum rigidity and reduced deflection
• Right-hand spiral flute promotes efficient chip evacuation during through-hole and blind-hole drilling
• Straight cylindrical shank fits standard drill chucks and collets without an adapter

Compatibility

Designed for use in any drill press, CNC machining center, turret lathe, or hand drill accepting a 5/16-inch straight cylindrical shank drill bit.

Installation Notes

Secure the shank fully in the chuck before operation and verify runout is within acceptable limits for the application. Power down and lock out the machine before changing bits. Use appropriate cutting fluid or coolant when drilling ferrous metals to protect both the bit and the workpiece. Follow shop safety standards and applicable OSHA machine-guarding requirements during all drilling operations.