I believe this 'original' style of grinding wheel dresser is known as a "Geiger Wheel Dresser" but exists in many permutations and adaptations.
Link to a video showing its use:
Link to a Geiger web page: https://www.geigerssolutions.com/Wheel-Truing-and-Dressing.html
Probably...
These look like they are from a Starrett #59F (or knock-off) trammel set.
(Link in the previous message will not display until 'moderated' as I do not have the required 3 posts.)
These look like they are from a Starrett #59F (or knock-off) trammel set.
http://www.starrett.com/metrology/product-detail/metrology/metrology-products/precision-measuring-tools/calipers-dividers-trammels/Trammels/59F