2a thread class right-hand 0.688" thread length pan no. 2 head style 32 thread quantity per inch cadmium or zinc screw surface treated unf thread series
3a thread class right-hand 0.608" thread length flat countersunk head style 1.365" grip length 20 thread quantity per inch groove in bearing surface of head nickel surface treated unjf thread series
3a thread class right-hand 0.378" thread length flat countersunk head style 0.615" grip length 28 thread quantity per inch internal drive ribbed unjf thread series