This is an improved ball and socket joint for giufini's excellent PCB Workstation with Articulated Arms.
The author used HIPS for his ball and socket joints but I only print with PLA and PETG. With both materials, I ran into a number of problems getting the articulated arms to work well. Here's a summary of the problems I had:
I tried both versions of the alternative ball and socket design with heat shrink tubing but the heat shrink quickly breaks down and gums up the socket. Plus, the bend radius is also reduced with the heat shrink.
So I took a stab at designing an improved ball and socket joint. The biggest requirement is that the ball remain the same size so it fits all of the accessories in the original project. Here's the mods I made to the design.
I'm quite happy with the final result. All of the probe holders and accessories I printed still attach fine but I no longer have the problems with loose arms and balls popping out.