Hertel 66691569 Drill Bit Letter G Cobalt Tin 135 Deg

Product Description

The HERTEL 66691569 is a cobalt screw machine length drill bit sized to letter G (0.2610 inches decimal equivalent) with a 135-degree split point and a titanium nitride (TiN) coating. Screw machine length bits are shorter than jobber-length bits, which increases rigidity and reduces deflection when drilling in tight setups or on CNC machines, manual mills, and drill presses. The TiN coating reduces friction and extends tool life when cutting through ferrous and harder materials. This bit is intended for use by machinists, tool-and-die shops, and trade professionals requiring consistent hole tolerance in metal fabrication work.

This drill bit suits applications in production machining, maintenance, and repair environments where letter-size holes are required in steel, stainless steel, cast iron, and similar hard materials. The shorter overall length of 2.625 inches and the 1.4375-inch flute length make it appropriate for use in gang drilling fixtures, turret setups, and close-clearance drilling situations. Its heavy-duty grade designation reflects construction for demanding, repetitive metal-cutting operations.

Key Features

• Letter G size - 0.2610 inches decimal equivalent for precision hole sizing
• 135-degree split point reduces walking and lowers required thrust force at entry
• Cobalt construction provides heat resistance for drilling hard and abrasive metals
• TiN coating extends cutting edge life and reduces built-up edge on ferrous materials
• Web-thinned, parallel web configuration improves chip evacuation and cutting efficiency
• Screw machine (stub) length increases rigidity and minimizes deflection versus jobber-length bits

Compatibility

Designed as an OEM-style replacement or direct working substitute for letter G screw machine length drill bits used in standard straight-shank drill chucks across CNC machining centers, manual drill presses, and mill/drill setups accepting a 0.2610-inch straight cylindrical shank.

Installation Notes

Install in a properly sized drill chuck rated for the shank diameter before powering on the machine. Ensure the shank is fully seated and the chuck is tightened with a chuck key before beginning any cutting operation. Use cutting fluid or coolant appropriate to the workpiece material to preserve coating integrity and edge life. Inspect the cutting edges for wear or chipping before each use and replace when the split point geometry shows degradation to avoid oversized or out-of-round holes.