Threaded

Threaded describes objects bearing helical ridges (threads) designed to engage matching grooves on a mating part. Threads enable fastening, adjustment, and the conversion of rotational to linear motion. They are categorized as external threads (on screws or bolts) or internal threads (in nuts or tapped holes).

Thread forms and standards vary by region and application. Common systems include ISO metric (external M threads with a metric pitch, e.g., M6 x 1.0) and the United States Unified Thread Standard (UNC for coarse, UNF for fine). Pipe and conduit threads use other profiles, such as NPT or BSPT, specified to seal or mate correctly. Key terms include major diameter, pitch diameter, minor diameter, pitch, and lead (for multi-threaded screws).

Manufacturing methods produce threads by cutting (tapping, threading dies) or forming (cold forming or rolling). Surface finish and tolerance are governed by thread grade and class, affecting fit and strength. Common quality checks use gauges and measuring instruments to verify pitch, diameter, and consistency.

In computing, threaded describes software that runs multiple threads of execution within a single process. Multithreaded programs can improve responsiveness and utilize multiple CPU cores but require synchronization to avoid race conditions, deadlocks, and data races. Common synchronization tools include mutexes, locks, semaphores, and thread pools.

In everyday language, threaded also appears as a descriptor for items designed to mate with threads, such as covers, caps, or fasteners, and broadly indicates the presence of helical threading for assembly.