Most sheet metal starts out as a flat sheet. It's then cut and formed using various tools in a sheet metal shop which allows a final product to be born. One of these sheet metal tools is a sheet metal roller, which contains three rollers that form the metal into a curved shape. For example, you could take a flat piece of sheet metal of a specific length and roll it into sheet metal pipe. The degree of roll formed is controlled by adjusting the third roller.
Examine your sheet metal roller on each for knobs. Twist each of these knobs counterclockwise to move the back roller away from the front two. The back roller should sit back approximately 1/4 inch to start with. Repeat this process for each knob on the bottom of the roller.
Lift up on the handle located on the right side of the roller. Press down on the lever located under the handle. The top roller should raise slightly. Slide your piece of sheet metal between the two front rollers and let go of the lever. Lower the handle and lock it into place.
Tighten each knob located on the bottom of the roller until the sheet metal begins to curl slightly in the roller.
Crank the handle on the side of the roller clockwise to draw the sheet metal through the roller. Once through, turn it counterclockwise to pull the sheet metal back out of the roller.
Adjust the knobs both at the back of the roller and underneath to tighten up the rollers. Draw the sheet metal back into and out of the roller. The tighter the knobs get, the more drastic the roll of the sheet metal.
Turn the handle counterclockwise to draw the sheet metal completely out of the roller once the desired roll is achieved on the piece.
If the roller is too tight and the sheet metal rolls too much, push down on the sheet metal as you are drawing it into the roller. This action will remove some of the roll for you.