Actually I thought of something I always wanted know about these type of interchangeable setups. How does the individual toolholder keep from spinning in the socket when under extreme loads? Is it simply the spring/air pressure from the contacts of the balls?
I have a little toolchanger called the Rapid Changer, and they first had issues with the toolholders spinning so they went with a heavier spring. Then, that didn't "completely" work so the went to toolholders that have radii cut out to mesh with the clamping balls, and while that worked, it was harder to get the toolholder to seat in the toolchanger properly.
Some pics for you.
Dave