Definition(s)
Black-Crested Thread
Non-full-crested thread whose original (black) mill surface has not been completely removed.
Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global Standards
Black-Crested Thread
Non-full-crested threads have historically been, and continue to be, referred to as black crested threads because the original mill surface has not been removed. The term black crested thread is a useful descriptive term, however, it should be understood that there can also be non-full-crested threads that are not black.
Source: API RP 5A5, Field Inspection of New Casing, Tubing, and Plain-end Drill Pipe, Reaffirmed August 2010. Global Standards