It turned out that his training as a machinist had everything laid out to center dimensions. My training in construction had everything measured to outside dimensions. My 8' wall didn't match up with his expectations. Who'd thunk? We eventually solved the problem, and the cabin is still here across the road 40 years later. Don't get me started on metrics, although I can make use of a 13 mm box end.
Worked in a glass factory where this took place. Building a cinderblock room to house the blowers for a new glass furnace. The machinery wound up barely fitting.