2a thread class right-hand hexagon head style 18 thread quantity per inch concentric circle at point; used on scott aviation (cagec 53655) regulators, p/n 800013 passivate surface treated unf thread series
Used on propeller hub onboard 378 ft whec coast guard vessels. 2a thread class right-hand 3.750" thread length hexagon extended washer head style 4 thread quantity per inch unc thread series
3a thread class right-hand 0.312" thread length double hexagon w/hole head style 28 thread quantity per inch silver threads surface treated unjf thread series
3a thread class right-hand 0.560" thread length double hexagon w/hole head style 28 thread quantity per inch silver threads surface treated unjf thread series
2a thread class right-hand 1.330" thread length round w/wrench flats head style 18 thread quantity per inch pellet type locking feature in threads unc thread series