Screwthreaded

Screwthreaded describes components or features that include screw threads, a helical ridge that mates with a corresponding threaded part. Such threads convert rotational motion to linear displacement and provide detachable connections with defined clamping force. They are common in fasteners, fittings, actuators, and many machinery assemblies.

Threads follow standard forms and dimensions. Common types include ISO metric (M, diameter in millimeters with a matching pitch), the Unified Thread Standard (UNC for coarse, UNF for fine) in North America, British Whitworth (BSW), and pipe threads such as BSP and NPT. Internal threads pair with external ones.

Key geometric parameters include major diameter, minor diameter, pitch diameter, and pitch or lead. The pitch is the distance between adjacent threads; lead is the axial advance per turn for multi-start threads. Tolerances define fit classes that govern how tightly parts screw together.

Manufacturing methods include thread cutting with taps or dies, and forming processes such as thread rolling. Finishing, lubrication, and surface treatments influence performance and corrosion resistance. Correct mating requires compatible standards and tolerances, verified with go/no-go gauges or thread pitch measurements.

Applications span fasteners (screws, bolts), threaded holes, pipe and tube fittings, and machine components such as lead screws and power screws. The screwthreaded concept underpins interchangeability and reliability across many industries.