Phantom Thread : A circumferential tool mark on a round thread chamfer that precedes the actual starting thread. Usually referred to as a false starting thread. (RP 5A5)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}