Hertel 74131905 Screw Machine Drill Bit Letter Q Cobalt

Product Description

The HERTEL 74131905 is a screw machine length drill bit sized to Letter Q (0.3320 inches decimal equivalent) and built for high-performance drilling in demanding shop and field applications. The bit is manufactured from cobalt steel and finished with a TiAlN coating, making it well suited for drilling hard and abrasive materials including stainless steel, hardened alloys, and cast iron. The 135-degree split point reduces walking on entry and lowers the thrust needed to start the hole. Overall length is 3 inches with a 1-11/16-inch flute length, keeping the tool compact for screw machine and close-tolerance work. A web-thinned, parallel-web construction reduces cutting resistance through the full depth of cut.

This bit is used in production drilling, machine shop work, and maintenance applications where short overall length improves rigidity and reduces deflection. The straight-cylindrical shank seats directly in standard drill chucks and collets without adapters. Right-hand spiral flutes clear chips efficiently during through-hole and blind-hole operations. The TiAlN coating extends tool life in dry or minimal-lubrication cutting conditions, which is common in HVAC fabrication shops, sheet metal operations, and general mechanical work.

Key Features

• Letter Q size - 0.3320 inches decimal equivalent, within the 0.3000 to 0.3500 inch size range
• 135-degree split point for self-centering entry and reduced thrust
• Cobalt steel construction for heat resistance in hard-material drilling
• TiAlN coating extends tool life in dry and low-lubrication cutting
• Web-thinned parallel web reduces cutting resistance
• Screw machine length (3 inches OAL) improves rigidity and minimizes deflection
• Straight-cylindrical shank fits standard drill chucks and collets without adapters

Compatibility

Designed as a direct-fit replacement for standard Letter Q screw machine length drill bits with straight-cylindrical shanks used in bench-top drill presses, CNC turret lathes, and hand-held drill applications requiring short-length geometry.

Installation Notes

This bit is installed by machinists and maintenance trades using standard drill chucks or collet-style tool holders. Ensure the shank is fully seated and the chuck is tightened before operation. Inspect the cutting edges for wear or chipping before each use, and replace when point geometry degrades to avoid work-hardening the base material. Follow applicable shop safety procedures including eye protection and secure workpiece fixturing.