A brake-shoe tool is for use with a brake-shoe lining. The brake-shoe tool includes an elongated rigid linear shaft assembly and a plurality of rigid flat plate members each rotatably mounted to the elongated rigid linear shaft assembly. Each of the rigid flat plate members includes a flat planar surface in rotating contact arrangement with a neighboring instance of the flat planar surface. A free end extends from the flat planar surface. The free end presents an elongated edge having a unique length. The elongated edge is configured to be positioned adjacent to a thickness of the brake-shoe lining in such a way that each instance of the elongated edge is positionable to and visually comparable against the thickness of the brake-shoe lining.