RE: O.S. .46 AX - bad rear bearing - metal shards... (pic heavy)
I learned a long time ago that it's *never* a good idea to try and get "just one more flight" from an engine once you notice that the bearings are going.
All those bits of metal are the reason why I now only use bearings with a polymer retainer instead of a steel or brass one. Bits of plastic won't cause nearly the same amount of damage if they break free. I think that all the 6902 bearings from rc-bearings.com have polymer retainers now and they're dirt-cheap too.
And you'd be well-advised to add a few oz of castor to that Coolpower fuel (or run Omega) so as to avoid rust in your other engines too. Besides which, *all* ABC/ABN engines will last much longer if they're run on fuel with a bit of castor in it.