Balax 10803-010 Extension Thread Forming Tap 4-40 H3

Product Description

The BALAX 10803-010 is a 4-40 UNC extension thread forming tap designed for producing internal threads without cutting flutes. Instead of removing material, it displaces and cold-forms metal to create strong, burr-free threads. Built from high-speed steel with a bright, uncoated finish, it measures 4 inches overall length with a 9/16-inch thread length. The bottoming chamfer allows threading close to the bottom of blind holes. At a 0.1410-inch shank diameter and H3 thread limit, this tap delivers consistent dimensional accuracy for close-tolerance applications. It is installed by machinists and maintenance technicians working with ductile metals in production or repair environments.

This extension tap is suited for applications where standard-length taps cannot reach recessed or deep-set hole locations. The extended overall length provides the reach needed in fixtures, castings, or assemblies where a standard tap would fall short. The 4-40 thread size targets small fastener applications common in light mechanical assemblies, electrical enclosures, and precision hardware. The 2B class of fit meets standard tolerance requirements for most general-purpose threaded fastener applications. Right-hand flute direction follows conventional threading operations.

Key Features

• Thread forming design cold-forms metal for stronger, burr-free threads without chip generation
• Bottoming chamfer allows threading to the base of blind holes
• H3 thread limit provides controlled oversize tolerance for consistent 2B class of fit
• 4-inch overall length extends reach into deep or recessed hole locations
• High-speed steel construction handles a wide range of ductile workpiece materials
• Bright, uncoated finish suitable for use with standard tapping fluids

Compatibility

Designed for use in 4-40 UNC threaded applications requiring an extension tap with a bottoming chamfer and 2B class of fit, typically in ductile metals compatible with thread forming operations.

Installation Notes

Thread forming taps require proper lubrication with a tapping fluid suited to the workpiece material - do not run dry. Ensure the tap is correctly aligned to the hole axis before applying torque to prevent tap breakage. Power down and secure any machine tool before changing or installing tooling. Consult applicable shop standards and the workpiece material specifications to confirm thread forming suitability before use.