English wheel

The English wheel, in Britain also known as a wheeling machine, is a metalworking tool that enables a craftsperson to form compound (double curvature) curves from flat sheets of metal such as aluminium or steel.

The process of using an English wheel is known as wheeling. Panels produced this way are expensive, due to the highly skilled and labour-intensive production method, but it has the key advantage that it can flexibly produce different panels using the same machine. It is a forming machine that works by surface stretching and is related in action to panel beating processes. It is used wherever low volumes of compound curved panels are required; typically in coachbuilding, car restoration, spaceframe chassis racing cars that meet regulations that require sheetmetal panels resembling mass production vehicles (NASCAR), car prototypes and aircraft skin components. English wheel production is at its highest in low-volume sports car production, particularly when more easily formed aluminium alloy is used.

Where high-volume production runs of panels are required, the wheel is replaced by a stamping press that has a much higher capital setup cost and longer development time than using an English wheel, but each panel in the production run can be produced in a matter of seconds. This cost is defrayed across a larger production run, but a stamping press is limited to only one model of panel per set of dies. The English wheel model shown is manually operated, but when used on thicker sheet metals such as for ship hulls the machine may be powered and much larger than the one shown here.

The machine is shaped like a large, closed letter "C". At the ends of the C, there are two wheels. The wheel on the top is called the rolling wheel, while the wheel on the bottom is called the anvil wheel. (Some references refer to the wheels by their position: upper wheel and lower wheel.) The anvil wheel usually has a smaller radius than the rolling wheel. Although larger machines exist, the rolling wheel is usually 8 cm (3 inches) wide or less, and usually 25 cm (9 inches) in diameter, or less.

The rolling (top) wheel is flat in cross section, while the anvil (bottom) wheel is domed.

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