Hertel 66691940 Cobalt Screw Machine Drill Bit Size 18

Product Description

The HERTEL 66691940 is a cobalt screw machine length drill bit designed for high-speed drilling in tough materials including alloy steels, stainless steel, and hardened workpieces. It carries a wire gauge size 18 designation, which corresponds to a decimal diameter of 0.1695 inches. The 135-degree split point reduces walking on entry and lowers thrust requirements compared to conventional 118-degree points. A titanium nitride (TiN) coating extends surface hardness and reduces friction at the cutting edge. At 2.125 inches overall length, the screw machine format provides extra rigidity over jobber-length bits, making it well suited for close-clearance drilling on drill presses, turret lathes, CNC machining centers, and manual metalworking setups.

This bit is intended for production machining and maintenance repair operations where drill life and hole accuracy in metal are priorities. The short overall length and straight cylindrical shank allow direct mounting in standard drill chucks and collet systems without adapters. Web thinning reduces cutting resistance at the chisel edge, which is particularly useful when drilling into pre-hardened stock or stainless alloys. Machinists, tool-and-die technicians, and maintenance mechanics working in fabrication shops, production floors, and industrial maintenance environments will find this bit appropriate for repetitive drilling cycles where a standard HSS bit would dull prematurely.

Key Features

• Cobalt construction provides heat resistance for drilling hardened and abrasion-resistant metals
• TiN coating increases surface hardness and reduces cutting friction for extended tool life
• 135-degree split point reduces drill walk and lowers feed force on entry
• Web-thinned parallel web geometry reduces chisel edge resistance
• Screw machine length (2.125 inches OAL) delivers greater rigidity than jobber-length alternatives
• Straight cylindrical shank at 0.1695 inches diameter fits standard drill chucks and collet holders

Compatibility

Designed as an OEM-style replacement or direct-use screw machine drill bit for standard drill chucks, collet holders, and turret lathe tooling that accept a 0.1695-inch straight cylindrical shank.

Installation Notes

Installation and use should be performed by qualified machinists or maintenance technicians familiar with metalworking drill practices. Secure the shank fully in the chuck or collet and verify runout before drilling. Power down and lock out the machine before changing bits. Do not exceed the recommended RPM range for the workpiece material and bit diameter, and apply cutting fluid as appropriate for the material being drilled to maximize tool life.