Whimbling iron

A whimbling iron is a bell clapper made from ductile iron.[1] Traditionally bell clappers were standard cast grey iron with a razor-like crystalline structure that led to sudden catastrophic failure over time. The standard clapper is distinguished by the experienced ear as a whefting iron. Whilst some believe that the advent of "health and safety" led to the search for an alternative, it is more likely that the ability to forge the bottom end ready for use practically died out early in World War II. Some attempts at composite clappers were made, but advances in casting technology, driven as much by the motor industry as by the war, resulted in the adoption of spheroidal graphite iron castings.[2]