Leroy Lettering templates helped draftsmen, architects, mapmakers and others annotate technical drawings with neat, consistent text. They were also used to letter comic books in the 1940s and 1950s, including the first Wonder Woman stories (Klein 2023).

A Leroy template defines the characters of a font with grooves routed into its face. As the draftsman follows the grooves with a stylus mounted on a hand-held device called a scriber, a pen attached to an arm of the scriber draws the letters. A pin at the other end of the scriber is placed in a straight groove running the length of the template to keep the letters in alignment.

The letters were created using a Gorton pantograph. The template consisted of a layer of white plastic laminated on top of a black layer. The router was positioned to cut through the white layer and into the black layer, making the letters easy to see (Keuffel 1936). Most Leroy templates use a font derived from the "Gorton" font (Wichary 2025).

The system was invented in 1937 by William J.D. Keuffel and Herman Esse, who started a company selling drawing tools and supplies in 1867 after immigrating from Germany. By the early 1900s, it was one of the largest sellers and manufacturers of technical and scientific instruments in the world. The company was notable for introducing the slide rule in the United States (Ziegler-McPherson 2018). The adoption of calculators in the 1970s and computer-aided design in the 1980s and 1990s led to the purchase and ultimate dissolution of Keuffel & Esser.