Hi Gath - The benders I have been involved with used a hydraulic ram and a chain. The chain runs around a sprocket on the bending lever. The chain runs to a spring for the return or another ram. On the CNC ones there is an encoder on the axis. Even if the machine is fully CNC you will still muck up the forst couple getting them symmetric. Springback and tube tolerances are always different tube batch to batch. Cheers Peter