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Fundamentals Of Internal Splines

January 18, 2022

Fundamentals Of Internal Splines

Splined shafts are integral to the functioning of different types of machinery and equipment across various industries. They facilitate effective torque transfer, thus enabling machines to perform at their total capacity. Some consider splines to be better than gears in enabling torque transfer. The spaced teeth or ridges in splines allow splined shafts to be fixed to gear or pulleys for transferring torque between mechanical components. There are mainly two types of splines—external and internal splines.

In this blog, we shed light on the internal spline's functioning and fundamentals.



Simply put, external splines have teeth or ridges cut on their outer surface; meanwhile, you will find slots cut on the inside of internal splines. External and inside splines together facilitate rotary motion to an external mechanical component or an output with the help of shafts. 


The ridges of the external spline perfectly fit between the inside spline slots or grooves to facilitate rotary motion.

How are they manufactured?


Various industrial processes are used to manufacture internal splines, some of which are shaping and broaching. 


With the exponential rise in the application of technology for industrial purposes in the last few decades, gear and spline manufacturing have mainly become automated. Gear manufacturers use CNC machining to process larger quantities with accuracy.


The involute, parallel key, crowned, and helical are four types of internal splines commonly used in automotive and heavy machinery industries. Involute splines come in different styles: flat root side fit, fillet root side fit, and major diameter fit are some of the examples. These splines are used extensively in manufacturing various types of engines.


For all kinds of dependable gears and splines, you can count on True Gear & Splines. With years of experience and a diverse clientele, we have established ourselves as one of the best names in the industry. Contact us today to learn about everything we can do for you.