3b 2nd end thread class 6 1st end bolt hole quantity one hole centrally located in flange face, six holes equally spaced on a bolt circle dia of 0.240 in. min, 0.260 in. max, around center hole unjf 2nd end thread series
3b 2nd end thread class 4 1st end bolt hole quantity 12 2nd end thread quantity per inch flange holes threaded 4-4ounc-2b 0.25 full thd un 2nd end thread series
3b 2nd end thread class 4 1st end bolt hole quantity 12 2nd end thread quantity per inch unc 0.138-32 rh threaded at 90.0 deg to bore 0.156 in. from boss end passivate surface treated un 2nd end thread series