Grey hammer has revolute joint with green slider.
It is connected to blue press shaft via violet conrods of double Hook joints. There is an offset E1 between the blue shaft and the grey hammer. There is also distance E2 between upper Hook joint of the conrod and the blue shaft axis.
The hammer compresses and twists orange forged part at the same time. Twisting is required for some forging operations.
The video shows using yellow screw to adjust the distance E2 to get various stroke lengths of the green slider.