Emuge BU396A00.5003 Thread Forming Tap 4-40 Unc Bottoming

Product Description

The EMUGE BU396A00.5003 is a bottoming-style thread forming tap designed for chipless internal thread production in steel and stainless steel. Manufactured from High-Speed Steel-E-PM (powder metallurgy HSS), it carries a TiN-T26 coating for improved wear resistance and surface lubricity. The tap produces 4-40 UNC threads to a 2BX class of fit with an H3 thread limit, making it well-suited for precision blind-hole applications where dimensional consistency is critical. Overall length is 2.2047 inches with a thread length of 0.4331 inches and a maximum tapping depth of 0.7087 inches. Licensed machinists, tool and die makers, and mechanical assembly technicians are the primary installers.

This tap is intended for blind-hole threading operations in ferrous materials, specifically steel and stainless steel, as indicated by material application codes P and M. The bottoming chamfer with 1.5 to 2 chamfered threads allows threading close to the bottom of a blind hole, which is a common requirement in precision machined components, aerospace fastener applications, and close-tolerance mechanical assemblies. It is part of the EMUGE BU396A00 Series, marketed under the InnoForm 1-VA/E-SN-PM-TiN-T26 trade name, and is not designed for cast iron, aluminum, or non-metallic materials.

Key Features

• Chipless thread forming process eliminates chip evacuation concerns in blind holes
• High-Speed Steel-E-PM construction provides uniform carbide distribution and extended tool life
• TiN-T26 coating reduces friction and improves resistance to galling on stainless steel
• Bottoming chamfer (1.5-2P) allows threading to within millimeters of hole bottom
• H3 thread limit and 2BX class of fit ensure consistent thread gauge compliance
• Right-hand thread direction; no coolant-through feature required for standard applications

Compatibility

Designed for blind-hole thread forming in steel and stainless steel workpieces. Produces 4-40 UNC internal threads to 2BX class of fit. Not rated for cast iron, aluminum, or plastics based on available material application data.

Installation Notes

Thread forming taps require a specific forming tap drill size - not a standard cut-tap drill - to achieve the correct pre-form hole diameter; consult the EMUGE forming tap drill chart for the 4-40 UNC forming drill specification. Power down and lock out all machine tools before loading or removing the tap from the holder. Use an appropriate tapping fluid rated for steel and stainless steel to reduce forming torque and extend tool life. Inspect the tap for flank wear or surface damage before each use, as forming taps operating in stainless steel are subject to galling if lubrication is insufficient.