This are fusion 360 source files for my 3d printed ball bearings, with steel balls. With this files you can easily create any size ball bearings, all you have to do is enter the size of the steel balls you intend to use and the dimensions of the ball bearing you'll like to make, the model will take care of the rest.
Video - https://youtu.be/RPXKK6NsMaM
3.5mm steel balls- https://amzn.to/2SmMMgy
100% infill, and try to print without stringing.
Engineer, maker and a designer