This piece originally ran in the April 2024 issue of EAA Sport Aviation magazine.
Aircraft drawings connect designers to the engineers who build our favorite aircraft, so legibility is key. Before word processors and CAD software, the Leroy lettering set was used to fill in the title blocks of aircraft drawings. Produced by the Keuffel and Esser Co. and patented in 1936, this lettering template was used by drafting professionals from the 1940s through the 1970s. To use this kit, they would select a laminated template with the appropriate font size. Then they would use the scriber tool, which has two connected pens. The movement of one pen, in tracing the letter on the template, produces identical movements in a second pen that reproduces the letters off the template.