Hertel 74131319 Screw Machine Drill Bit Letter T Cobalt

Product Description

The HERTEL 74131319 is a screw machine length cobalt drill bit sized to Letter T (0.3580 inches decimal equivalent), designed for high-production drilling in tough materials. The 135-degree split point reduces walking and decreases thrust, making it well suited for hard metals, stainless steel, and heat-resistant alloys. At 3-1/16 inches overall length, the shortened flute-to-shank ratio of screw machine geometry provides added rigidity over jobber-length bits. The web-thinned parallel web construction improves chip evacuation and extends tool life in production environments. The straw finish indicates a heat-treatment stage consistent with HSCo (high-speed cobalt) tooling. This bit is handled by machinists, tool-and-die tradespeople, and maintenance mechanics.

This bit fits applications where a standard jobber-length drill would deflect or chatter under load. Common use cases include drilling hardened steel, stainless fastener clearance holes, and close-tolerance work in CNC or manual drill press setups. The straight cylindrical shank seats directly in standard Jacobs-style chucks and collet holders. The 1-3/4 inch flute length accommodates typical workpiece thicknesses encountered in sheet metal fabrication, pump housing repair, and general machine shop work. The right-hand cutting direction is standard for conventional spindle rotation.

Key Features

• Letter T size - 0.3580 inches decimal equivalent, within the 0.3500 to 0.4000 inch range
• 135-degree split point reduces drill walk and lowers required feed force
• Cobalt (HSCo) tool material handles elevated cutting temperatures in hard and abrasive metals
• Web-thinned parallel web improves chip flow and reduces cutting resistance
• Screw machine length (3-1/16 inches OAL) delivers greater rigidity than jobber-length equivalents
• Regular spiral flute with right-hand cut - compatible with standard drill press and CNC spindle rotation

Compatibility

Designed as a direct-fit replacement for Letter T screw machine length cobalt drill bits in standard straight-shank chuck systems. No special adapter is required for Jacobs-style chucks or ER collet holders accepting straight cylindrical shanks.

Installation Notes

Installation and use of this drill bit should be performed by qualified machinists or maintenance mechanics familiar with cutting tool selection and machine operation. Secure the shank fully in the chuck or collet before powering the spindle, and verify the workpiece is clamped before initiating the cut. Use appropriate cutting fluid for the material being drilled to manage heat buildup in cobalt tooling. Follow machine manufacturer guidelines and applicable shop safety standards when operating drill presses or CNC equipment.