3a thread class right-hand 1.130" grip length 20 thread quantity per inch 156000 single pounds per square inch shear strength nickel surface treated unjf thread series
2a thread class right-hand 0.241" thread length flat countersunk head style 32 thread quantity per inch passivate screw surface treated unc thread series
flush (flat) countersunk (included angle - less than 135 deg w or w/o chamfer) head style 0.438" grip length 1490 single pounds per square inch shear strength any acceptable surface treated