The Hertel Extension Tap is a precision threading tool designed for professional machinists and industrial applications. This 5/16-18 UNC tap features 4 flutes with an H3 ground thread form and bright/uncoated finish for optimal performance. Crafted from high-quality high speed steel, this standard hand tap with plug chamfer ensures clean, accurate threads in various materials. The extended 6" overall length allows access to deep holes and recessed areas that standard taps cannot reach. With a 3B class of fit, this tap provides the ideal balance between precision and ease of assembly for threaded connections. The extension design makes it particularly valuable for automotive repair, machinery maintenance, and manufacturing applications where deep threading is required. Part #G837611 from MSC Industrial delivers the reliability and durability professionals demand for threading operations.