The turning over process was done by a massive machine which held the blade whilst a mandrel swaged the blade end material over, much like the process of sheet metal spinning but on a much heavier scale…

That must be something to behold; thanks for the explanation!

I’ve got the (sheared-off) root of a Short Stirling blade which is incredibly heavy and strong; it is difficult to imagine the size of any machine-tool that would have the ability to form the blade-root in such a way.