A cutting or shaping mechanism is described in which the cutting or pressing force is applied to a moving blade or shaping assembly over a limited part of the length of that assembly, including where the assembly is in engagement with the work. The application of the cutting or pressing force is moved progressively along the assembly to cause the assembly to roll on the work and progressively cut or apply pressure to the work. The invention is particularly applicable to a rolling cut shear having a single moving blade assembly or a pair of oppositely curved moving blade assemblies.

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