Hertel 74131780 Screw Machine Drill Bit Letter D Cobalt

Product Description

The HERTEL 74131780 is a screw machine length drill bit sized to Letter D (0.2460 inches decimal equivalent), designed for high-performance drilling in tough materials. Built from cobalt steel and finished with a TiAlN coating, this bit handles elevated cutting temperatures and abrasive workpiece materials without premature edge wear. The 135-degree split point reduces walking on contact and lowers required thrust force, making it a practical choice for production drilling on manual or CNC machines. The web-thinned, parallel-web configuration supports efficient chip evacuation. Right-hand spiral flutes and a straight cylindrical shank make this bit compatible with standard drill chucks and collet systems.

This bit is suited for metalworking applications in machine shops, fabrication facilities, and maintenance environments. Its screw machine length profile - shorter overall length than a jobber bit - provides added rigidity and reduced deflection when drilling steel, stainless steel, cast iron, and other hard or work-hardening materials. The 2.5-inch overall length and 1.375-inch flute length keep the cutting zone compact, which is ideal for drilling operations on lathes, drill presses, and CNC machining centers where overhang must be minimized.

Key Features

• Letter D size: 0.2460 inches decimal equivalent
• Cobalt steel construction for heat and wear resistance in hard materials
• TiAlN coating extends tool life in high-speed and dry cutting applications
• 135-degree split point reduces thrust and prevents bit walking
• Web-thinned parallel web promotes efficient chip evacuation
• Screw machine length for added rigidity and reduced deflection
• Right-hand cut with straight cylindrical shank for standard chuck compatibility

Compatibility

Designed as a direct-fit screw machine length drill bit for use in standard drill chucks and collet holders accepting a straight cylindrical shank in the 0.2000 to 0.2500 inch diameter range.

Installation Notes

Installation and use should be performed by qualified machinists or tooling technicians familiar with cutting tool safety. Secure the shank fully in the chuck or collet and verify runout before beginning a cut. Follow the machine manufacturer and tooling supplier recommendations for speeds and feeds appropriate to the workpiece material. Inspect the cutting edge for wear or chipping before each use and replace if the edge is degraded.