Generic ball joints for camera mounts and other adjustments

For the articulated arm that holds the RaspberryPi camera on my Prusa Mini, I needed a way to fine adjust the viewing angle of the camera. So I opted to design a ball joint.

I did a number of prototypes to try out how much the socket should reach around the ball, to give a good grip but still can be pushed on without breaking. Also I tried different wall thicknesses and ball diameters.

To spare you from doing the same trials again, I am publishing my results and my .stl files here.

There are two different balls (10 and 12mm) and four different sockets. Only combinations with fitting diameters are sensible of course. Here are my results, all for PETG as material:

Ball A - Socket A
Very easy to snap together, keeps position but is not able to hold against any significant force, will snap apart relatively easily.

Ball A - Socket B (encloses the ball more than A)
Can also be snapped together relatively easily, but holds together much better than with Socket A. Should be able to hold a small camera module.

Ball A - Socket C (has thicker spring walls than B)
Is already slightly scary to snap together but will not break when doing so and stays on very well. Can withstand even a bit more force than Socket B, should have absolutely no problem to carry a Raspi camera.

Ball B - Socket D (bigger ball diameter)
For those that want to be on the safe side. Snaps together ok and holds very well. Also can withstand even bigger force than the smaller sockets. Should easily hold a normal action camera in position.

Print instructions

Print in PETG, standing upright on the flat side (see screenshot from PrusaSlicer), without supports. No post processing needed other than maybe removing the stringing if there is any. The parts came out well from a Prusa i3 Mk3S.

If the ball joint is very hard to move, simply move it back and forth a bit and it will wear in quickly.

Either use the parts in a remix to combine it with your application, or glue them to whatever part you would like to fine adjust.