3b thread class right-hand flat countersunk head style 32 thread quantity per inch internal wrenching facility 0.156 in. width across flats by 0.090 in. min deep located on head passivate surface treated
3b thread class right-hand flat chamfer head style 13 thread quantity per inch steel grade 1215 (uns G12150) in accordance with astm A108 may be used when required cadmium surface treated