To put it simply, splines are mechanical drive systems that transfer motion from an input to an output. If you want to gain a better understanding of internal splines, you have come to the right place. And if you are asking yourself, “what is an internal spline?” that is okay too. Here, we’ve carved out what internal splines are and how they are used within gearboxes. Start reading below for all the insight you could possibly need on internal splines.