Continuous Flight Auger couplings are the connections which are welded on the section lengths with Male & Female on either side to join with other section lengths to form the required depth for drilling.
Most of the connections are hexagonal with face to face 110, 148, 176, 190, 200 & 220. We also call it SW100-SW220.
Some CFA coupling are formed with six splines as well.
Some also need special bolt & hole to join Male & Female together.
On other hand, some couplings for Earth Drills/Auger drive unit are make in square form.
LHR Drilling Equipment has complete CNC machining facility to manufacture any type of Hexagonal or Square couplings.