Fatigue is the failure of a material or machine component caused by repeated or fluctuating stress, typically beginning with a tiny, undetectable crack at a point of discontinuity like a notch, hole, or machining mark. As the crack grows, stress concentration increases, accelerating the failure. Springs, including leaf springs, absorb shocks and vibrations through elastic deformation. In this study, fatigue testing of a leaf spring was conducted using a slider-crank mechanism based on impactor theory, with deflection readings measured using a strain gauge and load cell.