Try, try again.
This setup works well but it is a bit thick and heavy. These will work great in a situation requiring a joint which can reliably hold a heavy armature. There is, however, much to be improved.
Common threads
The first generation used some inexpensive armature threaded ball and stem components. These are not very reliable. A good threadlocker like Loctite 263 is supposed to make the joints essentially permanent and should require high heat to break a threaded joint apart. This seems reasonable and there is always silver solder if needs be.
Balls!
Another weakness of the common, inexpensive armature components is the low quality of the ball portion. To overcome this issue, our balls are made of "Grade 25" ball bearings. This means that they are held to a tolerance of 25 millionths of sphericity. That sounds impressive, but it is pretty run-of-the-mill for bearings nowadays for bearings of this size.