Back in the 60's just after I got out of college, I worked for a steel fabricator in Texas. One of our projects was a mobile launch tower for Vandenberg AFB. The project was so big that it required 3 different fabricators to work on it. The tower was 7 million pounds when complete and on wheels so that it could be moved away from the rock prior to launch. There were folding platforms every 10 vertical feet so that workers could service the rocket. The platforms when in the down position had to match the exact shape of the rocket within 1/2" and had to clear the rocket when raised. A set of plans was 700 E sheets (34"x44"). Part of my job was "quality control" to meet the exacting government specs. There was no government inspector onsite so we did what needed to be done. The platforms were all of unusual shapes and there were multiple platforms per level. They not only had to match the rocket, they had to match the adjacent platform. Each was about 10' x 10'. Now as most welders know when welding really oddball shapes, things warp. We had a full time crew that did the "straightening" with torches and rags dipped in a bucket of water. These guys were amazing as to how much they could alter the shape and adjust the different parts of the platforms that sometimes went in different directions. Of course the specs strictly prohibited heat straightening. Yeah right...