Quote Originally Posted by BuffaloJohn View Post
Hydraulic motor connected above the video window that is connected to the cylinder.

The base is probably twisting, but that is to finish the outside and inside of the pipe.

The ram is twisting so the interface flange is made and finished as well...

Pretty interesting process, probably sped up a little but not hugely, nice through put in making pipe...
But you can see in the video that the cylinder is not twisting. And even if it was, a piston rod is free to spin inside a hydraulic cylinder. So you can spin a base or mount all day long and it won't spin the piston rod. I'm not even sure how you would construct a hydraulic cylinder such that it could apply any appreciable torque to the piston rod. They have to be able to spin inside the bore of the cylinder.