Which series is commonly used for screws, bolts, and nuts in engineering applications?

The UNC series, which stands for Unified National Coarse, is commonly used in engineering applications for screws, bolts, and nuts. This standard is part of the Unified Thread Standard, which is designed to provide consistency and compatibility in fasteners utilized in mechanical assemblies. The coarse threads of the UNC series allow for quicker assembly and disassembly, making them particularly suitable for applications where components may need to be frequently taken apart.

Moreover, the UNC series aligns with the specifications commonly found in manufacturing and engineering practices in the United States, providing a reliable option for engineers when selecting fasteners for various applications. Its prevalence in the market and well-defined standards contribute to its common usage in the industry.

Other series, such as UNF (Unified National Fine), offer finer threads that are better suited for applications requiring tighter assembly and resistance to vibration. ANSI (American National Standards Institute) is an organization that oversees the development of standards for a wide array of engineering practices, but it does not specifically denote a thread series. Whitworth is a traditional British standard used primarily in the UK and less common in modern engineering in the US. Thus, the UNC series stands out for its broad applicability and effectiveness in various engineering contexts.