Abstract: A paper shear mechanism consists of a guillotine having a fixed blade and a pivoted blade. The cutting edge of the fixed blade is concavely curved so that paper to be cut as fed between the blades assumes a corresponding curvature and is given some longitudinal rigidity during the cutting operation. The pivoted blade is of composite structure to simplify the manufacturing process and thus reduce cost. Essentially, it includes a cutting section stamped from flexible sheet steel shim to provide a cutting edge with the desired nip angle. The flexible steel section is spot welded to a mild steel backing member with an elongated spring member sandwiched between the two. The spring member has a number of spring teeth which exert a force along the length of the flexible section to deflect its cutting edge laterally towards the fixed blade. By this means contact between the cutting edges is maintained along the length of a cut and relief between the facing surfaces of the two blades is provided.