I've posted these two catalog excerpts before. Pic 1 is from a c. 1930's Bonney, and Pic 2 is from a c. 1940's New Britain. When looked at together, they tell the story of the evolution of ignition wrenches and ignition wrench set production. From wrenches with individualized and specialized shapes and service openings tailored to specific brand ignition systems (i.e., magdynos, generators, etc), to standardized wrenches (miniature DOE) with standardized angles (15* x 60*, sometimes 75*) and openings (15/64" through 1/2") that fit various ignition systems. EDIT: Kudos to New Britain for making the linkages, because you won't see that openings-to-system allocation in the ignition wrenches section of other mfgr's catalogs, just the sizes.