Full Crest Thread Length : The length of machine threads, from the end of the machined threads, including the incomplete starting threads, where the crests have full form. (RP 5B1)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}