What is the name of the hole defect where the hole is correct at the surface, but bows as it becomes deeper?

The term for the defect where a hole appears correct at the surface but progressively bows or changes shape as it becomes deeper is referred to as "barreled." This condition typically results from improper machining techniques or tool wear, causing an undesired taper or curvature within the hole itself. A barreled hole can negatively impact assembly and functionality by leading to misalignment or poor fitment of components that interact with the hole, ultimately affecting the overall integrity of the assembly. Understanding this defect is crucial for aerospace assembly mechanics, as ensuring that all components meet precise specifications is vital for the safety and performance of aerospace structures and systems.