the center bolt needs to be movable. you also need another fence on the right , looking at the first pic. . i would attach a piece of all thread to the center, silver bolt. and pull it back past the other 2. . Then you have 2 fences and the silver bolt on one side , and the black ones on the other. . Lay your red hot straight steel between them. then with an impact wrench turn the center , now sliding bolt until it hits the existing stop. the only piece that needs to move is the silver bolt, in the first picture it would move 3? inches from the bottom to the top.