This photo shows the metal worker on which I formed the feed loop that became part of my 10-40 meter magnetic loop portable antenna.
The diameter of the feed loop required for the antenna was formed by adjusting the rolls to the proper tension, and as the handle controlling the rotation of the rolls is turned, the flat aluminum stock is forced through the 3 rolls, and the loop is rolled in to shape.
This procedure is done in stages, with the diameter of the loop checked, and adjustments made to the tension of the rolls, that controls the force being applied to the material, until the required diameter for the loop is achieved.
This small 3 in 1 metal worker is indispensable for jobs such as this one, and this machine is also capable of forming sheet metal brackets, shearing sheet metal, box forming, and more.
The finished antenna is shown here....