Osg 2951300 Spiral Flute Tap 4-40 Unc 2 Flute

Product Description

The OSG 2951300 is a spiral flute tap designed for cutting internal 4-40 UNC threads in a wide range of materials, with a specific focus on aluminum applications. Built from vanadium high-speed steel with a bright uncoated finish, this tap delivers reliable cutting performance in production and maintenance environments. The modified bottoming chamfer allows threading closer to the bottom of a blind hole than a standard plug tap. With a 50-degree helix angle and a right-hand spiral flute geometry, chips are evacuated upward out of the hole, reducing the risk of chip packing during tapping operations. This tool is well-suited for machinists, toolmakers, and maintenance technicians working with small-diameter threaded fastener applications.

The OSG 2951300 is used in applications requiring 4-40 UNC threads, particularly in aluminum components common to electronics enclosures, instrument panels, and light mechanical assemblies. The modified bottoming chamfer makes it practical for blind-hole work where full thread depth is needed close to the hole bottom. The H2 thread limit designation ensures a consistent fit for 2B and 3B class-of-fit thread tolerances, making it appropriate for both general-purpose and closer-tolerance assemblies.

Key Features

• Modified bottoming chamfer for threading closer to the bottom of blind holes
• 50-degree right-hand spiral flute geometry promotes upward chip evacuation in blind-hole applications
• Vanadium high-speed steel construction for durability in small-tap applications
• H2 thread limit supports 2B and 3B class-of-fit tolerances
• Optimized for aluminum material applications
• Bright uncoated finish suitable for use with standard tapping fluids

Compatibility

Designed for cutting 4-40 UNC internal threads with a 2B or 3B class of fit. The H2 thread limit makes this tap compatible with standard 4-40 UNC tapped hole requirements across aluminum and similar non-ferrous workpieces.

Installation Notes

This tap should be installed in a tap wrench, tapping head, or CNC spindle rated for small-diameter tooling. Power down any machine spindle and secure the workpiece before tool changes. Use an appropriate cutting fluid or tapping compound for the workpiece material to extend tool life and improve thread finish. Follow ASME B1.1 thread standard guidelines when verifying finished thread fit.