A hinge (with its plural being hinges) is defined as a device of the mechanical sort that has as its purpose the bringing together of two solid objects but there is more to hinges than just swinging. There are more than 24 different types of hinges to allow for sweeping motion of one part in relation to another. Hinge design permits swinging of doors, panels, lids, suitcase halves, some briefcases, laptop computers and even some cell phones. Many hinges are made of various metals, fewer are made with engineered plastics and centuries ago people made hinges with wood and leather. Many hinges allow motion through a limited arc but a few designs permit motion through nearly 360 degrees. Successfully selecting hinges requires some forethought. For instance, no one wants their car door to start to tilt because of metal fatigue. Should that occur, the door wouldn’t shut properly and thus safely. For this reason, it’s crucial to consider the total downward forces that will stress...