This hand tool will bend brass, copper, and zinc into circles or ovals. The came bender will bend the border channels, flat H's, and round H's in the three separate groves of the tool. You can make circles three inches wide and larger. It will not bend the single sided U channel. Roller should be lubricated as used. Aluminum frame screws onto a work bench. Forming rolls are 2-1/2" (63mm) in diameter.