yet another ball joint.
It started with my desire to reuse an old gorilla pod tripod. Their ball diameter is around 20.2mm.
The tolerances might depend on your printer. I had to give it some trial and error.
To make the design more robust (in terms of less dependent on your printers tolerances) I designed the “doublecup” that can connect two ballheads. The fit can be additionally tightened with a screw (hole diameter is 5 mm).
→ My recommendation: Print the ball and the double cup part.
Prints fine in PLA with 0.2mm layer height and no supports.
Consider printing in these orientations (with a brim for the double coup):

Remixes wellcome: Onshape or the provided step files.
The author marked this model as their own original creation.