What did Whitney's system change a repair job from, especially for military equipment?

Answer

From a bespoke commission to a simple swap-out

Before this system, repairs involved a craftsman spending hours hand-fitting a replacement; Whitney's system turned this repair job into a simple swap-out, drastically cutting time-to-readiness.

What did Whitney's system change a repair job from, especially for military equipment?
inventionProductionManufacturingideaWhitney