As an expert in the field of mechanical engineering with a focus on fasteners and threads, I can provide you with a detailed explanation of what a UNC thread is.

UNC stands for Unified National Coarse. It is a standard for threaded fasteners such as screws and bolts that is widely used in the United States and other countries that follow the U.S. standards. The term "coarse" refers to the thread pitch, which is the distance between the threads measured in inches. UNC threads have a relatively large pitch compared to other thread types, making them suitable for general-purpose applications where a fast, coarse engagement is desired.

The thread profile for UNC threads is defined by the Unified Thread Standard, which is a widely accepted standard in the U.S. and other countries. This profile is characterized by its 60-degree flank angles, which are common in many types of threads.

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This number pair is optionally followed by the letters UNC, UNF or UNEF if the diameter-pitch combination is from the coarse, fine, or extra fine series, and may also be followed by a tolerance class. Example: #6-32 UNC 2B (major diameter: 0.1380 inch, pitch: 32 tpi) Unified Screw Threads �� UNC, UNF and UNEF.read more >>