Immediate linking of tolerance theory to hardware fabrication in a sophomore design course

This paper describes a teaching methodology where in order to bring a sense of importance to the potentially "dry topic" of tolerances, classroom theory is linked immediately to practical machining and assembly exercises.An introductory sophomore design course at the U.S Coast Guard Academy involves a substantial laboratory element embracing basic drafting and more advanced 3D CAD instruction followed by several weeks of machine shop/laboratory immersion and hands on technical instruction.In previous years basic tolerance theory has been taught in the CAD part of the class and a small percentage of this theory was then realized in machining exercises later in the course.The result has been somewhat "hit and miss" in the educational goal of passing on an appreciation of tolerances let alone an enthusiasm for including them in subsequent work.The new methodology described in this paper links tolerances with some very specific machining exercises that were then undertaken within the same academic week.The functionality of parts produced was directly related to successful adherence to drawing tolerances much more clearly than any class paper exercise.The end result was a dramatic improvement in both machining work and the appreciation of the importance of engineer specified tolerances for both performance and manufacturing cost implications.The use of tolerances was also seen more frequently in subsequent course design exercises.