Box bones, I have to create this box, I tries with armatures blender, I have some issues at the joint and I want to ask if this method is the right aproach. How to join the two parts exactly and not have it deform.
What issues at the joint are you having?
Are you trying to use automatic weights? As long as your bones root is centred on the joint line, all you should need to do is select one half of the box, and assign that to the bone in question with a weight of 1.0.
You could even use a shape key instead, if you wanted.