2a thread class right-hand 0.109" thread length flat chamfer head style 40 thread quantity per inch navy special project relief between shoulder unc thread series
3a thread class right-hand 1.120" thread length fillister head style 28 thread quantity per inch furnished with unthreaded neck 0.151 min. to 0.161 max. length; 0.214 min. to 0.224 max. dia. unf thread series