What does UNC stand for in Unified Thread Standards?

UNC stands for Unified National Coarse, which is a standard for screw threads in the United States. This designation indicates a specific type of thread form that features a coarse pitch, meaning that the threads are spaced farther apart compared to fine threads. The Unified Thread Standard (UTS) encompasses various thread types used in manufacturing and engineering, ensuring compatibility and functionality across different applications.

The term "Unified" signifies that this standard is widely accepted and used across multiple sectors, while "National" refers to its origin and primary use in the United States. The designation "Coarse" indicates the nature of the thread pitch. Coarse threads typically provide greater strength in gripping and are often used in applications where greater resistance to stripping is needed, making them suitable for a wide range of fastening scenarios.

This standard has become the foundation for numerous applications in mechanical engineering, indicating not only dimensions, but also tolerances and specific characteristics essential for reliable performance in threaded components.