For my first test I decided to dome a piece of 19-gauge cold-rolled steel sheet. I cut a disc about 11 inches in diameter, and fitted the optional 8-inch radius anvil wheel. This is the sort of test that really gives me a good "feel" for how smoothly and quickly a machine does what it's designed to do. The metal rolled through the wheels effortlessly, and within a couple of minutes time, I had developed a smooth, consistent radius. When precision is required, I often use a radius template to measure the amount of doming I have developed. My goal was to dome the entire panel to a 12-inch radius, and it probably took about 6 minutes to get that much doming. The smoothness of the surface is controlled by several factors, including the uniformity of your pattern of tracks across the surface, and how close the curvature of the anvil wheel matches the shape you're trying to achieve. I kept my tracks around 1/4-inch apart, and that developed a very smooth finish, indeed. I also used the technique of "crossing" my tracks, or wheeling across the panel in several different directions.
The "domed disc" was a piece of cake, so I decided to try a more challenging project next; the side of a motorcycle gas tank. This is a favorite project of mine because it's a very curvaceous shape, with lots of changes in contour. While I could have done the shaping on the English wheel, I decided to rough out the shape by hand to speed the process. I cut a piece of 1/16-inch 3003 H-14 aluminum to size, annealed it, and roughed it into shape with a teardrop mallet and sandbag.
Once satisfied with the overall shape, I did some smoothing by working the metal against a flat wooden board with the mallet, and then I went straight to the wheel. I did as much smoothing as possible with the 8-inch radius anvil wheel, but had to change to the 5-inch wheel for the highly crowned edges. In just a few minutes I had created a beautiful panel, nearly smooth enough to be polished.
Next, I cut a blank of 1/16-inch-thick aluminum to make a hood scoop. This project was considerably more difficult than the first two, since it required a lot more doming, plus I planned to form a rolled edge on the front opening and a mounting flange around the base.
I annealed the panel, and used the mallet and bag to quickly develop the rough shape. When I was satisfied with the depth, I quickly took the worst bumps out of the panel by using the mallet, hammering against wood. With the panel partially smoothed, I went to the English wheel, which developed a glassy surface very quickly. With the panel smoothed out, I saw a few areas that needed more doming, and I did that very quickly by wheeling locally in those areas.
Satisfied with the depth, shape, and smoothness, I was ready to move onto the edge details. I decided to put a 3/4-inch flange on the base of the scoop. I used 3/4-inch masking tape to quickly lay out this width, without marring the finish of the metal. Next, I used an old metalman's trick to form the flange. I put a spacer under one side of the axle on the anvil wheel, which moved the wheel's contact patch from the center to the wheel's outer edge. Then, using very light pressure between the wheels, I rolled the panel carefully between the wheels, keeping the edge of the wheels aligned with the edge of the tape, and lifting the scoop body about 15 degrees with each pass. It wasn't long until the flange was at the proper angle, and a little hammering trued the flange to perfection.
The rolled edge on the front of the scoop was started in the same way, and brought up as far as possible on the wheel, then rolled around to 180 degrees with the mallet, supporting the scoop body with the sandbag. The photos show just how well this came out, and the whole scoop was finished in about an hour.
6. For the next test, I decided to make the side of a motorcycle gas tank from aluminum. The shape was roughed out with a mallet and sandbag, and then partially smoothed by working against a wooden board.
7. Here’s the start of the final smoothing. I’m using the optional 8-inch radius anvil wheel here, and I used a 5-inch radius wheel for some of the more tightly radiused areas.
8. After about 10 minutes of wheeling, the tank side is completely smoothed.
9. I decided to make a hood scoop next. I cut a piece of aluminum sheet to size, annealed it, and worked it with a mallet and sandbag to get the rough shape.
10. Here I’m smoothing the part in the English wheel, using the 8-inch radius anvil wheel.
11. I plan to put a 3/4-inch flange on the bottom edge of the scoop, and I’m using masking tape here to lay out the inner edge of the flange.