Summary

Very strong ball joint that I made from the following criteria:

• Must be easy to print consistently good
• Must be easy to assemble
• Must be fast to print
• Must be durable with a locking mechanism to prevent the female part from breaking

I tried 5 different approaches to designing it, before settling on this one that may look a bit clumsy but it still satisfies all the above criteria.

Simply print two "ball-shell" parts and one "bolt" part to test it out for yourself. 

Print Settings                                            

Rafts:                     

Yes

Supports: 

No

Resolution:                     

0.15

Infill: 

20%

Notes:                    

Recommended settings:

• 0.15mm layer height for better details and a smoother top sphere
• 4 walls for added strength
• Infill density 20% max. (more will not do anything but give you a longer print time)
• Print on raft with 10-15mm extra margin
• Fan speed at full power to get the overhangs as good as possible. This is not super crucial; I forgot to turn on my fans one time, and the print was still usable, but looked like something that a wild animal had mauled, left and forgotten.