Thanks again Guys. But no, the bolt doesn't hit anything - and the extra length of the bolt probably saved my model from coming completely apart in the air. I've always steered-away from metal wing-bolts in the past, but these days I don't mind using them whenever I need to - they "seem" safer when I'm flinging my models around in the air anyway

Over the years I've had my fair share of crashes (haven't we all) but I don't remember any where the wing-bolt let-go in the way that it's supposed to do - always it's the wood that's broken. My most recent crash-tested model was a Funtana. It did a "pancake landing" after the engine died whilst prop-hanging - too low to build-up enough speed to land properly but high enough to have got the model turned-around into a landing attitude. The arrival wiped-out the u/c and the front of the fuz right back to the middle of the wing, and again it was the 1/4" ply plate wing-bolt retainer-plate which gave-way. Some years ago I began cutting the wing-bolts about half-way through in order to make the bolt the "weak link" that it ought to be, but it made no difference, that bolt was still intact whilst the rest of the model got damaged - sometimes totalled even. So . . . . if I have a metal bolt I'll probably use it

Removing the blind nut isn't a difficult job btw - I just gently push at them with a hot soldering iron and they soon drop out (make sure that the hot nut doesn't land on an area of film though as it may burn right through! I'll remove the bolt later today and take a look at it

You may be right about the nut damaging the bolts, but they both went in there ok, and they tightened-down ok too. It was only after 15 or so flights that I discovered the thread had stripped - and I hadn't needed to remove the wing in-between-times, so something definitely happened whilst the bolt was in-place

Tony