The purpose of DIN 5463 is to ensure that keys and keyways are designed and manufactured to a standard that ensures:
Published in the mid-to-late 20th century and reaffirmed in various editions (most notably the 1976-10 version), this standard specifies the dimensional characteristics of straight-sided spline profiles. Unlike involute splines (DIN 5480 or ISO 4156), straight-sided splines have parallel flanks, making them simpler to manufacture but less optimal for high-stress applications. din 5463 pdf