Assuming the other identifications within the collection have all been “correct”, the list produced here contains slide rules in the collection for which to date I have not been able to positively identify their makers. Fairly detailed depictions are presented in order for others to view and possibly help in determining their proper maker’s identity.
Total number of unidentified slide rules in the collection: 4.
L0 is the length of a decade on the main scale;
Lx is the overall length of the slide rule.
||1820||wd||12||24||no||nice condition; clear standard Gunter scales and brass pins|
||1880||wd||9||9||no||nice boxwood Comparative Rule for alcohol taxation, likely from a Sikes’ hydrometer set; one side does comparative values; other side does reducing calc|
||1940||wd||12||20||no||18 inch proportions rule, perhaps used in printing, engraving; maker? American Blueprint? (similar construction to U.S. Military Rule); A/B scales range from 1 to 30, 12 inches from 1 to 10|
||1970||pl||5||5||no||Made in Japan; ALCO?; from my high school years; note C and rho gauge marks|