2a thread class right-hand 0.230" thread length knurled no. 5 head style 56 thread quantity per inch concentric parallel threaded hole in threads dia. nom. 0.138-18unc-2b passivate surface treated uns thread series
3a thread class right-hand 0.780" thread length flat countersunk head style 0.449" grip length 24 thread quantity per inch cadmium surface treated unf thread series
Used on trgi 50011 radar type 93. 3a thread class right-hand 2.595" thread length double hexagon extended washer head style 20 thread quantity per inch unjf thread series