These parallel-rules from the 1940s were made to last out of ebony and brass. An essential piece of equipment for draughtsmen they were very effective in drawing two, or more, parallel lines. One such use was to place guide lines when hand lettering horizontal text where base and top lines were needed to maintain a consistent character size. They are seen partly open in this image.
Ebony & Brass Parallel rules (1940s) was last modified: July 19th, 2016 by