ABSTRACT
Nowadays it is unusual for components with serious faults to find their way into service, principally because of the rigorous quality control procedures used in manufacture. However, from time to time failures are encountered and, when the fault has a serious weakening effect, failure often occurs on the first occasion the component comes under heavy load. Chapter 2 quoted the example of a set of racing wheels for a sports car, one of which had spokes drastically thinned down to where they blended into the hub due to poor machining practice. The outer part of the wheel broke away from the hub as the car entered the first curve in a race, traveling at about 160 mph. The tire and outer rim bounced over the safety barrier into the crowd and the car struck the barrier and was almost completely wrecked. There was nothing seriously wrong with the metal or the casting — the responsibility rested entirely with the firm that undertook the machining.
