Hertel 74131756 Letter a Cobalt Screw Machine Drill Bit

Product Description

The HERTEL 74131756 is a screw machine length drill bit designed for high-productivity drilling in metal and hard materials. Built from cobalt steel with a TiAlN coating, it handles elevated cutting temperatures and abrasive workpiece materials that would quickly wear standard high-speed steel bits. The split point geometry at 135 degrees reduces walking on entry and decreases the thrust required to start a hole without a center punch. At 2-7/16 inches overall length, the stub-length body provides rigidity in short-reach drilling applications. Licensed machinists, tool-and-die technicians, and production shop operators are the primary users.

This drill bit is suited for drilling ferrous metals, stainless steel, cast iron, and other hard alloys in CNC machining centers, drill presses, and hand-held drill motors where stub-length rigidity is preferred over jobber-length reach. The Letter A size corresponds to 0.2340 inch decimal diameter, placing it in the 0.2000 to 0.2500 inch drill bit size range. The straight-cylindrical shank seats directly in standard drill chucks without an adapter. It is a common choice for production runs requiring repeatable hole size and finish.

Key Features

• Cobalt steel construction resists heat buildup during high-speed or dry cutting operations
• TiAlN coating extends tool life on abrasive and hard ferrous materials
• 135-degree split point reduces entry walking and lowers required feed pressure
• Web-thinned, parallel-web configuration improves chip evacuation and reduces thrust
• Screw machine (stub) length of 2-7/16 inches overall provides superior rigidity over jobber-length alternatives
• Right-hand spiral flute with regular helix geometry for controlled chip flow

Compatibility

Designed as an OEM-style replacement or direct-use screw machine drill bit for standard drill chucks and collet systems accepting a straight-cylindrical shank in the 0.2340 inch diameter class.

Installation Notes

A licensed machinist or qualified shop technician should confirm spindle speed and feed rate against published cobalt drill speed-and-feed tables before use. Secure the straight-cylindrical shank fully into the chuck to the recommended grip depth before starting the spindle. Coolant through is not supported on this bit, so external coolant or cutting fluid should be applied at the cutting zone when drilling harder alloys. Inspect the split point for chipping or wear before each production run.