Used on f-104 starfighter acft. 3a thread class right-hand 2.9300" overall length 0.3120" bore diameter 20 thread quantity per inch differentiated by 0.0701 in. hole centered on flat of shank 0.640 in. from center of bore cadmium surface treated single row, concave rollers unjf thread series
3a thread class right-hand 5.3980" overall length 1.2500" bore diameter 18 thread quantity per inch cadmium inner ring surface treated single row, ball unf thread series
3b thread class right-hand 2.8000" overall length 0.2500" bore diameter 28 thread quantity per inch cadmium all external/exposed metal surfaces surface treated double row, staggered, ball unf thread series