Tolerance piling was a huge lesson: each little discrepancy compounds across assemblies, so shop drawings specify gaps

https://lanesjes676.capitaljays.com/posts/dormers-you-can-count-on-the-honest-aging-of-hand-fabricated-copper

Resistance stacking was a big lesson: each tiny discrepancy compounds across assemblies, so shop illustrations specify voids, shims, and slot lengths to ensure a best website fit.