Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:4581142.
EDIT 27/6/2021
Okay, it is time to actually go ahead and finish this design, I looked around thingiverse for better design inspiration, I found a design but had to design it in CAD by myself, 3 pieces now, you will need:
-Super Glue -M5 Nut -M5x20 Bolt
The Ball will need adhesion support, The side piece doesn't anything, Arm only needs supports in the vertical part where the ball will sit, use a Cura plug in to disable supports for the M5 Bolt, or prepare to clean out with a drill.
Smooth your ball if you want to, I just ground it against the ball plates until it felt smooth, you will want to place four 4 dots of super glue in each corner of the arm's ball plate, insert the ball and squish with the other plate. add more superglue to any gaps.
I have deleted the old text, its completely redundant and frankly embarrassing