Osg 1400104908 Thread Forming Tap 4-40 Unc Bottoming

Product Description

The OSG 1400104908 is a thread forming tap designed for producing internal 4-40 UNC threads without cutting, instead displacing material to create a stronger thread form. Built from cobalt high-speed steel and finished with a TiCN coating, this tap delivers increased hardness and heat resistance for demanding tapping applications. The bottoming chamfer (1-1.5 thread chamfer length) allows threading to the bottom of blind holes with minimal clearance. With an overall length of 1.875 inches and a tapping depth of 0.559 inches, it is sized for compact fastener applications common in precision machining and light fabrication work. Right-hand thread direction and a Class 3B fit with H3 thread limit meet standard UNC tolerance requirements.

This tap is suited for blind hole threading in a range of ferrous and non-ferrous materials including alloy steel, carbon steel, die steel, hardened steel, stainless steel, and aluminum. It fits into tight-tolerance production environments where thread strength and consistency are critical, such as aerospace, tooling, and precision equipment manufacturing. The 4-40 UNC thread size is common in instrumentation, electronics enclosures, and small mechanical assemblies. This tap is part of the OSG HY-PRO NRT Series 14001, which is engineered specifically for roll-forming applications in these material groups.

Key Features

• Cobalt construction provides elevated heat and wear resistance compared to standard HSS taps
• TiCN coating reduces friction and extends tool life in abrasive or hardened materials
• Bottoming chamfer (1-1.5P) enables threading close to the bottom of blind holes
• Thread forming (chipless) design eliminates chip evacuation issues and produces stronger threads
• H3 thread limit and Class 3B fit for consistent, tight-tolerance UNC thread production
• Right-hand thread direction, compatible with standard tapping equipment and tap handles

Compatibility

Designed for blind hole thread forming in alloy steel, aluminum, carbon steel, die steel, hardened steel, and stainless steel. Material application codes P and N apply. Part of the OSG HY-PRO NRT Series 14001.

Installation Notes

Thread forming taps require a properly sized forming hole — not a standard drill tap hole — so consult the OSG HY-PRO NRT series forming hole chart before drilling. Power down and secure all workpieces before tapping operations. Use appropriate tapping fluid or cutting oil for the material being threaded to reduce heat buildup and extend tool life. This tap is intended for use by machinists and tool operators familiar with thread forming processes and standard tapping equipment.