Originally posted by SSGGeezer My father in law rebuilt at least one part of every F-18 model at one time or another as a machinist working at a Naval Air Rework facility, (NARF) and told me every time he had to re install a specific panel, the fit and drilled out parts for fasteners was different from plane to plane and never was the standard that you would expect from the factory if they are assembled on a line.
No two are identical.
They are built to the nearest 0.001" of an inch.
The ones I work on have a wingspan 212'7", are 242'4" long, and 60'8" high. It takes tens of thousands of bolts and rivets to put a structure that big together. The riveting causes the structure to grow some, and a temperature change of ten degrees will make a big difference too. Finishing parts fitted after the structure is completed are often made to be fitted to each plane individually, at the time of installation.
So that 0.001" inch tolerance can add up.
Amazing machines.