Cylindrical surface and its tolerance verification play important role in machining process. Although there exists many approaches that can fit the maximum, minimum and minimum zone cylinders, the cylinder fitting problems can even be further simplified. The methodology developed in this paper seeks to reduce the number of parameters used in cylinder fitting model using the projection model. The model evaluates 3-D tolerance specifications by introducing the optimal direction of projection such that the 2-D point projected onto this direction has optimal tolerance specifications (maximum, minimum and minimum zone circles). Besides, a global optimum solver, Particle Swarm Optimization (PSO) is applied to avoid the problem of finding local optimum. The proposed simplified method shows consistent results when compared with the results from literature.