Used on tf30 acft engine. 3b thread class right-hand 16 thread quantity per inch dwg name nut-bearing, internally threaded, 4.875-16 x 1.020 silver surface treated
2b thread class right-hand 24 thread quantity per inch contains three holes, 0.047 in. dia., evenly spaced, 0.378 in. from center of hole to center of nut