Definition - What does Pin down mean?
The pin down is a term referring to the male end of a drill stem component that extends from the tube body. The drill collars, and most components of the drill stem, have or accept this type of threaded connection. Pin ends are designed to mate with a box end. Properly connected ends ensure that drill strings are sound, and are a basic concept in trenchless drilling processes.
A pin end may also be called a male end.
Trenchlesspedia explains Pin down
The pin down aspect of a threaded drill stem connects to a receiving part which features an counter-constructed thread end. A crossover, or bit sub, can be used to convert threads so they are compatible. Box up connections mate to pin down counterparts and pin up connections mate to box down counterparts. Ensuring that the components of the drill stem have appropriate connections is paramount to assembling a complete drill string during trenchless construction operations.