5.19 Sterling, Acu-Rule, Festus, USA
Festus Manufacturing made slide rules beginning in 1938 in Festus, Missouri, USA. The company was renamed Acu-Rule Mfg. Co. in 1939 and produced slide rules branded as Acu-Rule and Acu-Math. The company later relocated to St. Louis, Missouri and then to Mt. Olive, Illinois in 1954. Eventually Acu-Math became the standard brand for the Acu-Rule Mfg. Co.
Sterling Plastics made slide rules in Mountainside, New Jersey, from about 1961-1972, and were another manufacturer of rules often used by students. Several of those shown in the collection are mine from my high school years in the 1970’s. In 1969 Sterling Plastics merged with Acu-Rule, and Acu-Math became the standard brand of the Acu-Math Division of Sterling. Sterling was subsequently purchased and became a division of Borden Chemical Co. in 1970. Slide rules were produced by Borden until 1972.
Total number of Festus, Acu-Rule and Sterling slide rules in the collection: 14.