@Jaime Mondragon. He is setting the fold rollers manually. By placing 1 thickness of say 70g/m2 uncoated paper in the quick set No.1 calliper on the outside of the machine, you then wind a strip of the same paper through the same No.1 roller nip. Then you adjust the fine adjustment dial on the calliper until the paper can be just drawn through the roller nip. This needs to be done on both sides of the machine and in sequence - roller 1, roller 2 etc. with all the buckle plates and deflectors removed. And the rear slitter shafts as well. Once this is done you can "zero" the +/- dial on each calliper. The principle of this is that whatever type of paper and however many thicknesses of paper are placed in the callipers, that manual set pressure on the folding rollers is maintained. This should be done say every 3 months maybe. When a brand new machine is installed, the factory have set the rollers and callipers. But they need to be re-calibrated because the levelling of the machine frame at the manufacturers is not exactly the same as on the new location. Hence the calibration may be slightly different. Plus the operator will have his own preference for the setting of the roller pressure. Hope all this makes sense. Try to find a copy of "Folding In Practice" by Alfred Furler which was compiled for the Stahl Folding Machine Company. It is the Bible for paper folding.
Warning! Do not do what these guys are doing - setting the rollers with the machine running! To be safe, please wind the paper strip into the machine. It takes longer to re-calibrate but it is safer.
