4.20 Unidentified

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.


Gunter Rule.

Comparative Rule.

Printer’s Proportions Rule.

Unidentified Rule from Japan.

Total number of unidentified slide rules in the collection: 4.

Year Mat Size Case Notes
1840 wd 24 no nice condition; clear scales and brass pins
1880 wd 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 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 no Made in Japan; ALCO?; from my high school years