Ready for a bigger challenge, I decided to make a trough-shaped piece, longer than could be done with the wheels in the standard position, and to make it a reverse curve to make things even more interesting. A reverse curve is concave in one direction and convex in the other; it's generally considered the most difficult shape to create and control. If you've never tried to make a reverse curve, it's guaranteed to drive you crazy the first few times.
I rotated the wheels 90 degrees, and carefully re-aligned them with a straightedge. Next, I cut a piece of aluminum to size, and used a special technique to put the first curve in the panel, the one that crosses the panel in the shorter direction. For this procedure, the wheels are adjusted to have very light pressure, the metal is pushed in straight, but then as the metal is rolled back out, I move my hands down toward the floor. Starting at one edge, I worked across the entire panel in this manner. This is a fast, easy way to get the initial cupped shape in the panel in the short direction, but it leaves the panel completely flat from side to side.
To develop the curve along the length of the panel, I rotated the wheels back to the initial position, and with fairly strong pressure between the wheels, I stretched the edges of the metal. What makes this even more challenging is that you can't stretch only the edge—the entire panel needs to be worked evenly. The edge gets stretched the most, but all other portions of the panel get stretched progressively; the closer to the edge they are, the more stretching they get, and the closer to the center, the less. The process is difficult to explain with words alone, but once you start working the metal, you will gradually come to understand what's going on, and "get the hang of it".
This panel required many, many corrections, but after about an hour, I was able to get a very smooth panel with a graceful curve from front to back, retaining a precise 6-inch radius across the shorter dimension.
These tests proved to me that the new Eastwood machine is very capable indeed, and I believe it would make a good addition to the shop or garage of anyone who wants to get involved with metal shaping.
12. The English wheel can be used as an effective flanging tool by angling the lower wheel, bringing the contact patch out to the edge of the wheels. I’m using a 1/4-inch spacer here to lift the axle on one side.
13. I will give this panel a reverse-curved shape. The first step is to give the panel a little curl across the short dimension, by working across the panel, pulling the panel down toward the floor as it is withdrawn from the wheels.
14.Here’s the finished scoop. This whole project took about one hour from start to finish.
15. To create a rolled lip on the front of the scoop, a flange is formed, and then it is worked back to a "J" shape with a mallet. The sandbag is used to support the scoop for this operation.
16. The flange is formed by trapping the metal between the wheels, aligning the edge of the tape against the edge of the wheels, and slightly lifting the panel as it is repeatedly rolled between the wheels.
17. One of the clever features of this machine is the ability to mount the wheels either parallel to the frame or perpendicular. Here I’ve removed the top yoke and I’m preparing to reposition it for working a very wide panel.
18. In this shot, you can see the uniform curvature across the short dimension, but it’s still completely flat across the long dimension.
19. The procedure for curving the panel in the other direction is to stretch the edge more than the center. This is done by applying a special tracking pattern, so that the tracks are more numerous near the edges of the panel.
20. Here’s the completed reverse curve. Note that I maintained a precise 6-inch radius on the entire part, while giving it a gentle curve in the opposite direction. This is a more advanced technique, but with a good English wheel it’s a joy when you learn how.