Tolerance Design for Orientation-Constrained Fits Between Two Parts

This chapter presents the orientation-constrained fits and extends the concept of fit boundaries to this case of fit. The concept of contact datum features and their method of labeling is shown. The fit assurance requires the use of perpendicularity tolerance for cylindrical as well as width features. Theoretical gages explaining the meaning of perpendicularity tolerance are presented. The concept of datum simulators is introduced. The importance of making datum features flat to prevent rocking and the use of flatness tolerance to achieve sufficient flatness is discussed.