The pin in design (a) serves both to transmit torque and to locate the ring axially on the shaft. Avoid the overdetermination of the axial position of the pin by the shaft shoulder by considering the one-diameter shaft design (b).

The matching of fillets in assembly (a) is expensive and usually not necessary. A simple countersink (b) eliminates the difficulty.

It is difficult to maintain close tolerances on distance `n" in the cast cover (a). A one-diameter bushing held in place by a set screw (b) simplifies the construction and permits some reduction in the length (and hence also the weight) of the cover (b).



Similarly, avoid matching recesses and shoulders [as is the case in (a)], if possible. A screw fastening (b) is more economical and in most cases equally efficient

The same principle applies to the assembly of flat surfaces.