Editing Screw thread (section)

===Taper===
Tapered threads are used on fasteners and pipe. A common example of a fastener with a tapered thread is a [[wood screw]].

The [[threaded pipe]]s used in some plumbing installations for the delivery of fluids under pressure have a threaded section that is [[Threaded pipe#Tapered threads|slightly conical]]. Examples are the [[National pipe thread|NPT]] and [[British standard pipe thread|BSP]] series. The seal provided by a threaded pipe joint is created when a tapered externally threaded end is tightened into an end with internal threads. For most pipe joints, a good seal requires the application of a separate sealant into the joint, such as [[thread seal tape]], or a liquid or paste pipe sealant such as [[pipe dope]].