Definition - What does Pin up mean?
A pin up, in trenchless technology, is a drill bit's male end threaded with an upward profile. The term describes a feature of the threaded pin of a bottom hole assembly (BHA), the drill bit, in a drill string. The drill bit's male end, called the pin, is threaded upward into the bottom female thread of the bit sub, unlike other drill string components that have threaded pins that thread down toward the drill collars and bit sub.
Also referred to as a male end.
Trenchlesspedia explains Pin up
The pin up 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. The bit sub is a thick wall pipe with a female thread on both ends. Box down connections mate to pin up counterparts and pin down connections mate to box up counterparts. Ensuring that the components of the drill stem have appropriate connections is paramount to assembling a complete drill string during trenchless construction operations.