1a thread class right-hand 0.190" thread length headless (setscrew) head style 28 thread quantity per inch 2a or 3a optional classes for threads unf thread series
3a thread class right-hand 0.552" thread length headless (setscrew) head style A32 thread quantity per inch passivate surface treated unf thread series
2a thread class right-hand 0.407" thread length flat countersunk head style 32 thread quantity per inch passivate screw surface treated unc thread series