3a thread class right-hand 0.630" thread length hexagon head style 18 thread quantity per inch externally grooved under head 0.230 in. dia 0.090 in. w cadmium surface treated unc thread series
3a thread class right-hand 0.620" thread length hexagon head style 0.810" grip length 24 thread quantity per inch cadmium or zinc surface treated unf thread series
3a thread class right-hand 0.810" thread length hexagon head style 2.600" grip length 24 thread quantity per inch cadmium or zinc or chromate surface treated unf thread series