It was one of the main suppliers to major engineering firms in Québec during the thriving years of the late sixties, when the province was booming with construction activities—building highways and preparing for Expo 67.
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A special slide rule was designed in the mid-1930s by Nelson M. Cooke of the Navy's Radio Materiel School; many thousands of the 4139 Cooke Radio Slide Rule were made by K&E.
# Mechanical lettering is done using tools such as lettering guides, templates, or using a small mechanical pantograph referred to by the Keuffel and Esser trademark "Leroy"
Luke Esser | Markus Esser | Keuffel and Esser | Jan F. Esser |