4.2 Charvoz-Roos, USA

Both Charvoz, Inc., of East Rutherford, New Jersey (1939) and the Roos Company of New York City, New York (1941) were founded to manufacture replacement slide rules during World War II for companies in the U.S. that relied on foreign imports, including the Frederick Post Company. After the war, manufacturing ceased and the two companies merged into the Charvoz-Roos Corporation in 1946, selling imports such as Aristo and others until going bankrupt in 1953.

Total number of Charvoz-Roos slide rules in the collection: 6. \(~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\)

Model Year Serial Typ Mat Size Case Note
SR-104
1941 L wd 10 yes Made in U.S.A.; no company reference
SR-109
1941 L wd 10 yes Made in U.S.A.; no company ID; case (Tom Walsh); nice and precise
SR-109 1942 L wd 10 no Post 1457; Mannheim-Trig; WW-II; rough condition
PSR-105 1944-45 L wd 5 yes Post 1444-D; pocket Commerce rule; nice condition; made during WW-II; clear celluloid cursor; red leather case; table of fraction conversions on inside of stock; clean table of Equivalents on back
SR-108 1945 L wd 5 yes Post 1442; distinct C1/D1 C2/D2 scales
Power Trig
1945 L wd 10 yes Post 1462; brown leather case