Originally Posted by
hoistop
jimjim1 You are right regarding castellated nut holding duplex bearing. It is obvious that if failing bearing caused inner race to start rotating on shaft, this action would put UNSCREWING force to the nut if it has a normal, right tread - I believe it is. But nut stayed in place and only increased torque was reported.
Thanks hoistop jimjim1 ShyTorque for your thoughts and comments regarding the tightening of the duplex bearing nut. It seems we agree it would tend to unscrew on bearing lockup and I was just surprised by this apparent logical error in the report. But it is mentioned extremely briefly. Also it would make sense if the nut were tightened by the momentum of the rotating shaft when the blades were brought to a sudden stop and perhaps that is what was meant.
In any case I'm sure the issue of whether any possible range of torque values could contribute to a failure of this particular design of duplex bearing will be looked at.