Excerpt from Elements of Machine Design Based on the brief outline of the strength of materials given in Chapter I the author has attempted to develop the equa tions for the design of the more common machine elements. This has generally been done very concisely and frequently only an outline of the deduction has been given. Empirical formq and rule of thumb methods, so much used in elementary texts on this subject, have been avoided as far as possible. There are many factors which in practice affect the design of machine parts that cannot be discussed profitably in the class-room for instance, cost of construction, capacity of shop machinery, etc. For this reason the teacher must be content if the student acquires the power to analyze the forces and the resultant stresses in machine parts and to apply the proper equations for their design.