Spring return mechanism for returning the movable blade and connected slide plate to their at rest position in a flying shear. The device is positioned outboard of the movable and fixed blades, each of which has mating and alignable apertures through which long lengths of stock material to be sheared into shorter segments are continuously fed. Each device includes an upright elongated spring housing, a compression spring acting within the housing, and a guide button which moves up and down within the housing to return the slide plate and connected movable blade back to their at rest position immediately after each shearing. The guide button has an upper end which allows the slide plate to move or slide diagonally downward. The guide buttons follow the diagonal motion of the movable blade during each cutting cycle.