API SPEC 5B

Description

This specification covers dimensions, tolerances, and marking requirements for API threads and the gauges that control the acceptance criteria for the threads. Thread element gauges, instruments, and requirements for the inspection of threads for line pipe, round thread casing, round thread tubing, and buttress casing connections are included. All thread dimensions shown without specifications (or shown as NA) are not subject to inspection of diameter, ovality, and addendum. All thread dimensions shown without tolerances are related to the basis for connection design and are not subject to measurement to determine acceptance of product. Thread inspection applies at the point of manufacture prior to shipment, to inspection at any intermediate point, to inspection subsequent to delivery at destination, and to inspection by inspectors representing the purchaser or the manufacturer. The manufacturer may, at his or her option, use other instruments or methods to control manufacturing operat