3a thread class right-hand 0.671" thread length flat countersunk head style 28 thread quantity per inch navy special project cadmium screw surface treated unf thread series
flush (flat) countersunk (included angle - less than 135 deg w or w/o chamfer) head style 0.469" grip length 5240 double pounds per square inch shear strength cadmium bolt surface treated
3a thread class 1.200" thread length 24 thread quantity per inch threads interrupted by undercut 0.290 in. min, 0.320 in. max from drive end passivate surface treated unf thread series