Roll Bending @museum.de

Do you remember the old tinsmith Heinrich Thalmayer and the way he put his life on the line scrambling around right under the eaves? That was dangerous but unavoidable. Because manufacturing and installing gutters and downpipes is a very important field of work for metal roofers. But first, the sheet metal in the workshop actually has to be transformed into such a pipe or a gutter. And at this workplace, you can see how it's done. Here's where we deal with "roll bending" – that is forming a sheet of metal into a round shape.

If it's thin enough and small enough, a piece of sheet metal can simply be placed over a pipe or a cylinder and bent with sheer physical strength. Of course, first, the edges need to be blunted using a wooden hammer to prevent injury.

For larger and thicker sheets, you need a roll bending machine. The sheet metal is passed between three rolls: the upper and a lower roll control how the metal moves through the machine. And the adjustable bending roll is progressively tightened, gradually reducing the distance between the rolls and constantly narrowing the path the sheet metal has to take.

It takes a great deal of patience, because this kind of rolling process should always be carried out in several steps. However, ultimately if you persevere, you're rewarded with a perfectly round pipe!