Present paper collects significant works about cost-tolerance curves. Although the cost-tolerance binomial has a great relevance in mechanical manufacturing processes, getting an adequate relationship between cost and tolerance is still an unsolved problem. Collected works in this paper cover the main attempts to find a satisfactory solution from first developments to nowadays. The paper analyzes the features of each model and presents them using a uniform format in order to establish a comparison among them. Fortresses and weaknesses of each model are emphasized. From comparison results, a new approach to cost-tolerance curves is suggested. This approach is built from manufacturing process instead of extemal data like occurs in most of revised works.