3D Modelling, 3D Printing Stand for an extra ball for a CST trackball June 24, 2022 I have an extra ball for my CST trackball on my desk, and I decided to design a nice 3D printed stand for it. It uses a standard skateboard bearing and you can make the ball spin for a very long time (and by that annoy your colleagues endlessly). The ballbearing works works perfectly with this. The ball and the CST trackball. The bearing simply drops to the bottom of the stand.