External thd 1/2-20 unf, class 3a; o/a diameter 0.4919 to 0.5000 in.; hex through bore 0.1875 to 0.1895 in.; o/a h 0.175 to 0.185 in.; incl locking element 0.063 to 0.066 in. Dia; matl nut cres 347, 0q-s-763; matl locking element polytetrafluoroethylene ams 3651
