National Kaohsiung University of Science and Technology 1 article published in JoVE Engineering Generating Lap Joints Via Friction Stir Spot Welding on DP780 Steel Tai-I Hsu1, Meng-Hsiu Tsai2 1Department of Health and Beauty, Shu Zen College of Medicine and Management, 2Department of Mold and Die Engineering, National Kaohsiung University of Science and Technology Here, we present a friction stir spot welding (FSSW) protocol on dual phase 780 steel. A tool pin with high-speed rotation generates heat from friction to soften the material, and then, the pin plunges into 2 sheet joints to create the lap joint.