The double standing seam machine FK1 is used to fold double standing seams between 20 mm and 40 mm, suitable for profiled shapes turned-up at 90 degrees. For turned-up metal sheets, 2 seaming operations are necessary. The seam profile height is infinitely variable from 20 - 40 mm, depending on the profile turn-up height. For pre-profiled shapes with a profile height of 25 mm only one operation is necessary.