I'm re-assembling a DUKW that had the frame removed for sandblasting and painting. The problem is that the bolt holes don't line up. With the front of the frame hard against the front hull cross-member, the bolt holes at the front are off by a couple of hundredths of an inch. With a little more hammering, I can probably get them to fit. The problem is at the rear. With the front in place, the rear holes are mis-aligned by as much as 3/16". (the hull is now shorter than the frame.)
I doubt that welding shrinkage is the explanation, since almost all the patching was finished before the frame was removed. Another possibility is that while the frame was out (for a couple of years) the hull was supported better at the ends than in the middle. That would cause the ends to be pushed up relative to the middle, and that would move them inward. Given the quality of the war-time finish, the slight amount of wrinkling this would cause would not be noticeable. To test this theory, I have supported the middle on pallets and put weights on the ends. It's been that way for a couple of weeks, and so far there's no visible movement. I could add more weight, but obviously I'm afraid of breaking something.
If worst comes to worst, I could make the holes align by reaming them, but I know I shouldn't, and I hope it doesn't come to that.
Has anyone else had this problem, and if so, what did you do about it?