Bell-Mouthed

“Bell-mouthed” describes a hole or bore where the diameter gradually increases towards one or both open ends, forming a curved profile in section. This profile resembles the shape of a bell, hence the term. It’s typically considered a manufacturing fault because it can lead to issues such as poor fit, leaks, or uneven flow depending on the application. In contexts like machining or manufacturing, ensuring uniform and precise dimensions throughout the bore or hole is crucial to avoid bell-mouthing.