3a thread class right-hand 0.750" thread length hexagon head style 0.875" grip length 24 thread quantity per inch cadmium surface treated unf thread series
3a thread class right-hand 0.837" thread length flat countersunk head style 20 thread quantity per inch navy special project cadmium screw surface treated unf thread series
2a thread class right-hand 0.430" thread length flat chamfer head style 0.360" grip length 28 thread quantity per inch phosphate surface treated unf thread series