In 1942, Frank Szymanski switched from making cars on an assembly line to assembling B17 bombers for Boeing. He then realized that Boeing did not have a clue how to build wings for B17 quickly, perfectly, efficiently... so he showed them how to reduce the time from 20 hours to 2.

his ability to see the obvious, that management was oblivious to because they do paperwork, not stepping onto the assembly line and earning some calluses, brought the production of B17s from 14 planes a month to over 362.

And Boeing was weeks away from losing the contract, because their production was too slow

What was the initial problem Boeing wasn't clued into? Heat expansion. 

Hot rivets on one end of the wing would cause just enough thermal expansion that rivet holes on the other end of the wing wouldn't line up. 

So, he demonstrated that starting the installation around the main structure points, with the workers spread out, reduced thermal expansion, placing hot rivets at various distant points, where the metal was cool, spread the heat out, reduced the amount in any one area, and the rivet holes didn't get shifted elsewhere on the wing. 

If you want to listen to 40 minutes, plus commercials, etc that never seem to answer the question, until 70 percent of the way through the video, doesn't even start to address the issue until 14 minutes into the video after wasting your time with history, flashbacks, etc... then here it is, and as always, increase the play speed from 1.0 to 1.25 because video makers are deliberately slowing down the speed to waste your time for stats to earn more from You Tube