In general, involute spline torque (strength), and the diameter of the modulus, little effect; when the diameter is larger, the number of teeth, tooth modulus of deep processing, (material removal) are generally not used. If the tooth number is too much, processing, measurement is not convenient. The number of teeth can be considered from 30 to 40, and the standard modulus.

The spline shaft is a mechanical transmission, the key to peace, the semicircular key, oblique key role, is the transfer of mechanical torque, with longitudinal keyway in the shaft sleeve appearance, rotating parts on the shaft also have corresponding keyway, can be maintained with axis synchronous rotating. In the rotation at the same time, some can also be on the axis of the longitudinal sliding, such as transmission gear box, etc..