Gui Parallel Ruling Straightedge

A straightedge which is specifically designed to be used with a guide cord attachment. It has provisions for the assemblage of pulleys or a bearing clamp on each end of the blade for attachment of a guide cord which permits the straightedge to be moved over the surface of the drawing board. It may include all the necessary fittings for attaching to a drawing board, such as pulleys, bearing clamps, adjusting posts, cord, screws and the like.