Each fit class specifies tolerances for centering. Unlike involute splines which center on the flanks, straight-sided splines can center on the major diameter, minor diameter, or flanks. DIN 5463 typically centers on the .
: The primary fit and alignment between the shaft and the hub are controlled by the minor diameter ( din 5463 pdf
: The primary source for official DIN 5463 standards. Each fit class specifies tolerances for centering