In this Book, mathematical approach is discussed to synthesize the Quick Return Mechanism for desired output and specified input. The effect of variation in link length/s on the performance of Quick Return Mechanism is also discussed. The approach also helps in identification of most sensitive link/s in the mechanism. Computer programme in C# is also developed for the synthesis of Quick Return Mechanism, along with the optimized scheme of tolerance for desired permissible variation in the Stroke length (output). An optimum combination of linkages helps in selection of type of machine required for machining operation. The approach will also help in reducing the cost of manufacturing by providing optimum set of tolerance on individual link/s.