Interference fits between a shaft and its components can sometimes
be used effectively to minimize the need for shoulders and keyways [see Budynas p. 399]:
p = \frac{\delta}{\frac{d}{E_{o}}\left(\frac{d^2_{o}+d^2}{d^2_{o}-d^2}+v_{o}\right)+\frac{d}{E_{i}}\left(\frac{d^2+d^2_{i}}{d^2-d^2_i}-v_{i}\right)}