Emuge BU591410.5003 Thread Forming Tap 4-40 Unc 3BX

Product Description

The EMUGE BU591410.5003 is a thread forming tap designed for internal thread production in blind hole applications. Unlike cutting taps, thread forming taps displace material rather than cut it, producing stronger threads with no chips to evacuate. This tap is manufactured from High-Speed Steel-E (cobalt-grade HSS) and carries a Titanium Nitride (TiN) coating for improved surface hardness and wear resistance. It produces 4-40 UNC threads to a 3BX class of fit with an H9 thread limit, making it well suited for tight-tolerance blind hole work in steel, stainless steel, and non-ferrous metals. Machinists and tool-room technicians typically install this tool in CNC machining centers, turret lathes, or drill presses using a tapping head or rigid tapping cycle.

This tap is used in blind hole threading operations on small-diameter fastener threads in the 4-40 UNC inch series. The bottoming chamfer style, with 1.5 to 2 chamfered thread leads, allows threading close to the bottom of a blind hole. Its flute-by-diameter ratio of 3xD supports use in moderate-depth holes. Typical applications include precision components in metalworking, electronics enclosures, instrument panels, and light structural assemblies where chip-free thread formation is preferred. The InnoForm 1-MULTI/E-SN-TiN series designation indicates suitability across multiple material groups including steels, stainless steels, and non-ferrous metals.

Key Features

• Thread forming (chipless) design produces stronger threads than cut taps and eliminates chip evacuation concerns in blind holes
• High-Speed Steel-E (cobalt-content HSS) construction for improved heat and wear resistance over standard HSS
• Titanium Nitride (TiN) coating extends tool life and reduces friction during forming
• Bottoming chamfer with 1.5 to 2 chamfered thread leads for threading close to hole bottom
• 3BX class of fit with H9 thread limit for tight-tolerance thread production
• Right-hand thread direction; compatible with steel, stainless steel, and non-ferrous metal workpieces

Compatibility

Designed for blind hole threading of 4-40 UNC internal threads in steel, stainless steel, and non-ferrous metal workpieces. Suitable for use with standard tapping heads, rigid tapping adapters, and tapping attachments sized for a 0.141-inch shank diameter.

Installation Notes

Thread forming taps require a properly sized forming tap drill hole, which is larger than a standard cut tap drill - consult a thread forming drill chart for the correct pilot hole diameter before use. Ensure the tapping spindle is set to the correct RPM and feed rate for the workpiece material and hole depth. Apply appropriate tapping fluid or cutting oil rated for the workpiece material; this is especially important when working with stainless steel. Inspect the tap for wear or deformation before each use and do not force a tap that has stopped advancing, as breakage in a blind hole is difficult to recover from.