2a thread class right-hand 1.126" thread length pan head style 32 thread quantity per inch metallic-ceramic coat 0.0003-0.0006 inch thick per mil-c-81751, type 1, class 4 unc thread series
3a thread class right-hand 0.688" thread length flat countersunk head style 20 thread quantity per inch cadmium screw surface treated unjf thread series