I don't just buy the first thing I see either and I also have to be tight with my funds. Its not that I am tight wad it just common sense pay a fair price for things. Impulse buying can get you in trouble quick.
Exactly AVB - pay a fair price for things and look for a balance between price and a bit of quality; if the world didn't run out and buy the first thing they saw, the would be a lot less useless junk coming from China.
There is no damage to the nut or threads,so hopefully it didn't tighten before it came loose.
I will never be tightening effectively anything with the impact. I once had to remove a swing back blade bolt where the head had no hex, and the D shaped hole had been stripped by an impact. Ended up angle grinding the nut off.
With regards to the fin - its light aluminium. I tried to use some selleys epoxy on it - didn't work at holding the fin on, but the glue is stuck solid to the flywheel. At about the same weight as the fin its self, I don't think the bearings will take any damage from an uneven flywheel.
