Coupling Preload : Compressive bearing load developed between pin and box members at their interface; this is accomplished by elastic deformation during makeup of the coupling. (RP 2R)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}