The upper and lower shear drums of flying shears having respective shear blades are driven continuously by one motor at a tangential speed synchronized to the translational speed of a stock strip traveling therebetween, and the upper drum is moved between an upper non- shearing position and a lower position for cooperative shearing of the strip with the lower drum by an upper drum displacing mechanism driven by another motor controlled to undergo operational cycles each starting from full stop and ending at full stop during an integral number of revolutions of rotation of either of the drums.
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