How to adjust roll forming machine wheel gap?

Do you have a ruler in your factory? Or you can use your current 0.5-thick board to cut it into a small strip and put it in each row to test whether the gap is appropriate according to my video method? The appropriate state of the gap should be: after the ruler or slate is put into the roller, no matter which direction you turn the upper shaft, it should be very easy to rotate, but the premise is that the roller should touch the material.
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