A sheet metal object made on a brake will have corners (bends) and sides (flanges). On a forming machine, it is possible to make an object without sides. For example, you can make a circular object such as a funnel. The forming machines used in the Navy are usually located at aircraft intermediate maintenance departments (AIMDs). The two most common machines are the slip roll and the rotary.

SLIP-ROLL FORMING MACHINE. Sheet metal can be formed into curved shapes over a pipe or a mandrel, but the slip-roll forming machine is easier to use and produces more accurate bends. Rolling machines are available in various sizes and capacities. Some are hand operated, like the one shown in figure 13-27, and others are power operated. The machine shown in the illustration has two rolls in the front and one roll at the rear. You can adjust screws on each end of the machine to control

Figure 13-27.-Slip-roll forming machine.

the distance between the front rolls. By varying the adjustments, the machine can be used to form cylinders, cones, and other curved shapes. The front rolls grip the metal and pull it into the machine; therefore, the adjustment of distance between the two front rolls is made on the basis of the thickness of the sheet being worked.

ROTARY MACHINE. The rotary machine, shown in figure 13-28, is used on cylindrical and flat sheet metal to shape the edge or to form a bead along the edge. Various shaped rolls can be installed on the rotary machine to perform these operations, which are described later in the text.