Balax 10805-010 Extension Thread Forming Tap 4-40 Hss

Product Description

The BALAX 10805-010 is a high-speed steel extension thread forming tap designed for cutting 4-40 UNC internal threads in confined or deep-reach applications. Thread forming taps displace material rather than cut chips, producing stronger threads with no swarf to clear. This tap carries an H5 thread limit and a 2B class of fit, making it suitable for close-tolerance fastener assemblies. The bright, uncoated finish suits general-purpose use across a range of ferrous and non-ferrous materials. The extended overall length of 4 inches gives technicians clearance to tap holes that standard-length taps cannot reach. It is used by machinists, maintenance technicians, and toolmakers in production and repair operations.

The 10805-010 is built for bottoming applications where threads must run to the bottom of a blind hole. The 4-inch overall length and 9/16-inch thread length are suited to assemblies where the fastener engagement zone is deep within a workpiece or housed behind a structural feature. Applications include tapping enclosures, brackets, and light mechanical assemblies that use 4-40 machine screws. Right-hand flute direction matches standard right-hand thread cutting practice. The tap belongs to the BXEXT series, which covers extended-reach thread forming tools.

Key Features

• Thread forming design displaces material for stronger, chip-free threads
• 4 inches overall length provides extended reach into deep or obstructed holes
• Bottoming chamfer allows threading to the base of blind holes
• H5 thread limit with 2B class of fit for consistent close-tolerance results
• High-speed steel construction handles repeated use in production settings
• Right-hand flute direction for standard tapping operations

Compatibility

Designed for use with 4-40 UNC threaded hole applications requiring an extended-reach bottoming tap. Fits standard tap holders and extension handles sized for a 0.1410-inch shank diameter with a 0.1100-inch square drive.

Installation Notes

This tap is installed and operated by machinists or maintenance technicians using a tap wrench, extension handle, or compatible machine tapping setup. Ensure the workpiece is securely fixtured before tapping. Use appropriate cutting fluid for the base material to extend tool life and improve thread finish. Verify hole diameter and depth meet the 4-40 UNC pre-tap requirements before use.