Abstract: A bending brake for sheet metal employs a long, upwardly facing fixed clamping surface supported on a base, and a long bending arm hinged to one edge of the clamping surface. An upper clamping surface is supported for movement toward and away from the fixed clamping surface at the first ends of a number of arms which extend normally to the clamping surface and are pivotably supported near their opposite ends for rocking motion about the base. Actuating means taking the form of a cam mechanism or fluid cylinder acts between the far ends of the arms and the base to bring the movable clamping surface into and out of engagement with the fixed clamping surface.