Lead 16 : The distance that a thread moves along its longitudinal axis. The distance from a point on a thread to a corresponding point on the next thread, measured parallel to the axis of the thread section. (RP 5A5)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}