Used on h60 helicopter. 3b thread class right-hand 12 thread quantity per inch nut, bearing retaining-planetary assembly, main gearbox silver surface treated
2b thread class right-hand 11 thread quantity per inch coated, metallic-ceramic, mil-c-81751, type 1, class 4, 0.001 in. min, 0.002 in. max thk outer surfaces, 0.0005 in. in, 0.0008 in. max thk on thds, before inal sealer coating chromate surface treated