Hertel 74130386 Cobalt Screw Machine Drill Bit 27/64 in

Product Description

The HERTEL 74130386 is a cobalt screw machine length drill bit designed for drilling in tough materials where standard high-speed steel bits wear prematurely. Built to a 27/64-inch (0.4200 inch decimal) diameter with a 135-degree split point, this bit reduces walking on entry and requires less feed pressure to start a hole. The 3-3/8-inch overall length is suited to screw machine and close-tolerance drilling applications. Right-hand cutting with a regular spiral flute pattern, it is used by machinists, tool-and-die workers, and maintenance technicians working with stainless steel, hardened steel, cast iron, and other abrasion-resistant materials.

This bit fits production and job-shop environments where shorter flute length and rigid geometry improve hole accuracy. With a 2-inch flute length, the 74130386 is well matched to shallow-to-moderate depth holes in metal fabrication, automotive, aerospace maintenance, and general industrial settings. The straight cylindrical shank seats directly in standard drill chucks and collets without adapters. The straw finish indicates the cobalt content has been heat-treated to final hardness and is ready for use without additional coating.

Key Features

• Cobalt construction for extended tool life in hard and abrasive metals
• 135-degree split point reduces drill walking and lowers required feed pressure
• Web-thinned parallel web for improved chip clearance and reduced thrust
• Regular spiral flute pattern provides consistent chip evacuation
• Straight cylindrical shank fits standard drill chucks and collets
• Screw machine length for greater rigidity and improved hole location accuracy

Compatibility

Designed as a screw machine length replacement drill bit for use in standard drill chucks, collets, and drill press spindles accepting straight cylindrical shanks in the 0.4000 to 0.4500 inch diameter range.

Installation Notes

Secure the shank fully in the chuck or collet before operation and verify concentricity to minimize runout. Use cutting fluid or coolant appropriate for the workpiece material to maximize bit life, particularly when drilling stainless or alloy steel. Inspect the split point for chipping before reuse; a damaged point should be reground before continuing. Follow applicable machine shop safety practices including eye protection and proper workholding.