The scope of this information sheet includes involute splines (some of which are governed by ISO 4156 and DIN 5480)@ plus variants such as modifications to helix@ lead crown@ form diameters@ root geometry@ tooth thickness@ and fits and straight sided splines with parallel teeth in the external spline (some of which are governed by ISO 14). It also includes longitudinal effects such as the washout of the minor diameter in splines that are formed or cut into a shaft and hoop strength effects of hollow splined sections. A limited range of materials is included: hard steel@ soft steel@ powdered metal steel (PM)@ and cast iron. Manufacturing processes discussed include: rolling@ hobbing@ shaping@ milling@ broaching@ grinding@ net formed PM@ and cold forming. Rating for compressive@ shear@ bending@ and hoop stresses are covered@ as are tolerances@ lubrication@ and failure modes. Both elemental and attribute inspection of splines are included. It also describes drawing requirements@ and a troubleshooting guide.