3a thread class right-hand 0.413" thread length flat chamfer head style 24 thread quantity per inch setscrew's socket drive is counterbored; has a portion under the head which is 0.371 in. min. unf thread series
3a thread class right-hand 0.157" thread length flat chamfer head style 24 thread quantity per inch setscrew has a protion beneath the head which is 0.308 in. min. unf thread series