Abstract: The invention concerns a machine comprising: at least a brake coil, containing a wire to be strung; at least a roller for receiving, coiled about it, the wire unwound by the coil and for appropriately directing the wire for strining; and means for displacing the roller between a retracted position, where the roller is located on the near side the plane defined by two consecutive supports, and a projecting position, wherein the roller is located beyond the plane.