Because the thread on this this fuel filler cap was really really well cut, I was able to get the fit that I was trying for on the left wing. Oh well thats life. I also, don't ask me how, because I fitted and lined up this nose skin in exactly the same way, got the nose skin to make contact right at the tip of the rib, in the previous wing I had a gap of a few millimeters. I can only put it down to being more confident about what I am doing, plus my skills have to be improving. I guess like everyone, the next plane would be perfect.