Simple and sturdy ball joint adapter that can fit 1/4 -20 UNC, 3/8-16 UNC  or 5/8-27 UNC threads.

Assembly: Sit the desired ball into the base and screw on the cap and then the optional lock nut.

The 3 bases 1_4, 3_8, and 5_8 correspond to the 1/4 -20 UNC, 3/8-16 UNC  or 5/8-27 UNC female threads located at the bottom of the base.

Recommend printing with at least 20% infill and support touching build plate.

1_4 Ball (1/4 -20 UNC) is only recommended for light duty applications since a 3D printed ¼ bolt is not the strongest.

(Seen holding up GoPro)

1_4 Bolt Ball allows for screwing in a metal 1/4-20 UNC bolt which is much safer for camera use and other heavier duty applications.  Just make sure the bolt is at least 1" long with a head diameter of 10mm (~3/8") or less

(Seen holding up DSLR Camera)

3_8 Ball (3/8-16 UNC) is also capable but still not as safe as the metal ¼ bolt option.

(Seen holding up Shure SM7B Microphone)

Recommend printing any of the ball options and the Cap with 100% infill for maximum strength.