Hertel 66693557 Drill Bit Letter R Hss Tin 135 Deg

Product Description

The HERTEL 66693557 is a screw machine length drill bit designed for high-speed, high-production drilling in metal and hard materials. Built from high-speed steel (HSS) with a titanium nitride (TiN) coating, it delivers extended tool life and reduced heat buildup compared to uncoated HSS tooling. The 135-degree split point geometry reduces walking on contact and lowers the thrust required to penetrate the workpiece. At 3 inches overall length and a letter R diameter of 0.3390 inches, this short-body stub drill is suited for use in tight-clearance fixtures, drill presses, and CNC setups where rigidity matters. Installation is performed by machinists, tool and die technicians, and general metalworking trades.

This drill bit is used in screw machine shops, production machining environments, and general metalworking applications requiring a letter R size hole. The stub length body minimizes deflection during deep-feed operations in steel, cast iron, aluminum, and similar materials. The TiN coating provides a harder cutting surface and reduced friction, making it a good fit for repetitive production runs where tool longevity is a priority. It accepts standard straight-shank toolholders and collet chucks sized for a 0.3390-inch shank diameter.

Key Features

• Letter R diameter (0.3390 inches) with straight-cylindrical shank of matching diameter
• 135-degree split point reduces drill walking and lowers required feed pressure
• TiN coating extends tool life and reduces friction during metal cutting
• Screw machine (stub) length body at 3 inches OAL improves rigidity and reduces deflection
• Web-thinned parallel web configuration for improved chip clearance
• 2-flute regular spiral design for efficient chip evacuation in through-hole drilling

Compatibility

Designed for use in standard straight-shank drill chucks, collet chucks, and screw machine spindles accepting a 0.3390-inch shank diameter. Fits tooling setups within the 0.3000 to 0.3500 inch drill bit size range.

Installation Notes

This drill bit is installed and operated by machinists and metalworking technicians using standard drill presses, lathes, or CNC machining centers. Ensure the spindle and chuck are fully stopped and de-energized before inserting or removing the bit. Secure the shank fully in the chuck to the recommended grip depth to prevent pullout under load. Do not use this bit on materials or at feed rates beyond the capacity of the toolholder and machine setup.