I worked maintenance in an aluminum mill for years. When production would jam the screw downs on the reversing mill we would a use 48" pipe wrench and a 10 ton crane to turn the screw down shaft backwards to relieve pressure on the mill. Once, when production had done an absolutely stellar job of jamming the screw downs we broke every 48" pipe wrench in the plant trying to free the mill with no luck. We ended up using disks grinders (we called them our portable milling machines) to grind a flat across the the top 154" work roll. We then rolled the mill over till the flat we had ground  relieved enough pressure to free the screw downs. The mill was down 20 hours. Management estimated that when in full production having the reversing mill down cost the plant a thousand dollars a minute.