In this book experimental investigation of stepped threaded pin fin heat transfer has been explained using the materials brass and mild steel. Out of these two, one is stepped threaded and other is stepped pin fin of each materiel. The objective of this project is to determine the effectiveness and efficiency of stepped threaded pin fin and its comparison with fin like cylindrical experimentally. Also a detailed comparison of how much heat transfer takes place through both the materials. It was found that in case of stepped threaded pin fin surface area increases by 5.8 % as compare to smooth stepped pin fin. Temperature drop in stepped threaded fin is more than stepped fin.Temperature drop in also brass material fin is more than mild steel materials fin. efficiency of stepped threaded fin is greater than stepped fin.Heat transfer Coefficient, Nusselt number of stepped threaded fin is more than stepped fin.