What is the nominal diameter of bolts commonly referred to as?

The nominal diameter of bolts is commonly referred to as the major diameter. This term designates the largest diameter of a bolt, specifically the external diameter of the thread. It is a critical measurement when determining the appropriate fit and strength of a bolt in various applications, ensuring that it can handle the required loads without failure.

Understanding the major diameter is essential in the design process, as it influences factors such as load carrying capacity, clearances, and compatibility with nuts and other threaded components. The major diameter is also the reference point for specifying bolt sizes and is typically noted in standards and technical specifications.

The other options describe different aspects of threaded fasteners. The minor diameter refers to the smallest diameter of a thread, while the pitch diameter is the diameter at which the thread thickness and the space between threads are equal. The base diameter is not a commonly used term in design contexts related to bolts. Recognizing these distinctions helps in selecting the correct fastener for specific engineering applications.