Splines are used in mechanical rotating drive systems. Any device that transfers rotary motion from an input shaft to an output shaft most likely uses splines of one form or another.

A splined shaft is one that has equally spaced teeth around the circumference parallel to the shaft’s axis of rotation. These teeth can be straight sided, serrations or involute form. The externally splined shaft mates with an internal spline that has slots, or spaces of a mating form to the shaft’s teeth.

The rotation of the splined shaft is transferred to the internally splined member, such as a gear or other rotary device. The spline connection provides an equally distributed load along the sides of the teeth. This shared load provides a longer fatigue life verses a keyway drive.


Spline Cutting
Spline Types:

Parallel Key Spline: This type has equally spaced teeth that are straight sided. The teeth on the shaft have an equal tooth thickness at any point measured radially out from the axis of rotation. Conversely, the internal parallel spline has parallel spaces.
Involute Spline: This type has equally spaced teeth, but they are not straight sided. The teeth have an involute form, similar to an involute gear tooth.
Serrations: This type of spline has a tooth form that is non-involute. The teeth of the male detail are in the form of an included angle, with the female serration having spaces of the same included angle. Methods we use for producing splines.
Hobbing: All external spline forms can be produced with the hobbing method, dependant upon the limitations of the machine tool and the individual component design.
Shaping: This method can be used to produce both internal and external splines of parallel, involute or serrated type.
Broaching: This method is used to produce female splines of all types. The broach tool is specific to the internal spline it is designed for.
Milling: Serrations and parallel or involute splines can be milled on our range of 4 axis cnc milling machines.