Tolerance piling was a big lesson: each small inconsistency compounds across settings up, so store illustrations specify gaps

https://page-wiki.win/index.php/Hand-Fabricated_Copper_Cupolas:_What_Architects_Know--_and_Time_Verifies

Resistance stacking was a big lesson: each little inconsistency compounds across settings up, so shop drawings define spaces, shims, and port lengths to guarantee a perfect site fit.