Splines are machine elements that connect a shaft with a rotor. Next to transmitting torque, the spline might also be utilized to center the rotor to the shaft. It is interesting that the spline’s tooth profiles are involutes, although the involute profile does not contribute to the torque transmission, nor is it linked to the centering function. The reason for the involute profile is the fact that most external splines are manufactured by hobbing with a standard straight-sided, symmetric hob tooth profile that is fast and delivers good accuracy results.