Engineers are challenged daily to come up with economical product designs that reduce weight, size, raw materials and labor. This competitive mandate affects every design facet, including the fasteners needed to hold components in place. One style of non-threaded fastener that has been widely used to accomplish these goals is the retaining ring. A circular fastener, this ring is installed in a groove to hold components on a shaft or inside a bore. It holds gears, cams, and pulleys on shafts, and it keeps bearings, valves, nozzles and locks inside housings. Knowing which retaining ring to use in a given fastening situation can greatly contribute to the overall effectiveness and economy of a design. Just as a screw needs a correctly tapped hole, a retaining ring needs properly cut grooves to ensure the best performance. Both groove walls should be parallel and perpendicular to the axis of the shaft or housing. Groove depth should be held to specifications because the depth and the groove bottom radii determine the amount of support the load-bearing groove wall will provide. The edge margin, which is the distance of the groove from the end of the shaft or housing, must be calculate...