Hertel 66691791 Cobalt Screw Machine Drill Bit Size 3

Product Description

The HERTEL 66691791 is a cobalt screw machine length drill bit designed for high-performance drilling in hard and abrasive materials. Built to heavy-duty grade standards, it features a 135-degree split point that reduces walking and allows faster penetration with less feed pressure. The titanium nitride (TiN) coating extends tool life by reducing friction and heat buildup at the cutting edge. With an overall length of 2.375 inches and a flute length of 1.25 inches, this short-length bit offers maximum rigidity for precision work on drill presses, CNC machines, and manual drilling equipment in metal fabrication, maintenance, and production environments.

This bit is sized to wire gauge number 3, with a decimal diameter of 0.2130 inches, placing it in the 0.2000 to 0.2500 inch size range. It is suited for drilling ferrous metals, stainless steel, and other hard alloys where standard high-speed steel bits lose edge quickly. The screw machine length format makes it a common choice for production drilling where stub-length rigidity matters and drill press depth capacity is limited. Machinists, tool and die workers, and industrial maintenance technicians are the typical end users.

Key Features

• Cobalt construction rated for heavy-duty drilling in hard and abrasive metals
• TiN coating reduces friction, heat, and wear for extended tool life
• 135-degree split point minimizes bit walking and lowers required feed force
• Web-thinned parallel web configuration improves chip clearance and cutting efficiency
• Screw machine length provides maximum rigidity compared to jobber or long-series formats
• Right-hand spiral flute with straight-cylindrical shank for standard chuck compatibility

Compatibility

Designed as an OEM-style replacement or direct-use drill bit for any standard three-jaw or collet chuck accepting a 0.2130-inch straight-cylindrical shank, including most bench drill presses, CNC machining centers, and handheld drilling equipment in that capacity range.

Installation Notes

Installation is performed by machinists and industrial maintenance technicians using standard drill press or machining center procedures. Secure the straight-cylindrical shank firmly in a three-jaw or collet chuck before operation and confirm runout is within acceptable limits. Always power down and lock out the spindle before changing bits. Do not exceed the recommended feed rate for the workpiece material, as cobalt bits are rigid but can fracture under excessive lateral load.