The term "stencil saxophone" is actually a reference to a specific type of saxophone that was produced by one company but marketed and sold under a different name. This practice was fairly common during the early 20th century, particularly in the United States, when saxophones were experiencing a surge in popularity.
At that time, there were a number of saxophone manufacturers, including the likes of Conn, Martin, and Buescher, that were producing high-quality instruments for professional musicians. However, these instruments were often quite expensive, and not everyone could afford them. To make saxophones more accessible to a wider audience, some manufacturers began producing saxophones that were of slightly lower quality but still perfectly playable and functional. These lower-quality instruments were then sold under a different brand name, often to schools, military bands, and other groups that needed a more affordable option.
These lower-quality saxophones were often called "stencil saxophones" because they were produced using a stencil or template that had been created by the original manufacturer. The stencil would be sent to a different factory, where the saxophone would be manufactured and branded with a different name. For example, a Conn stencil saxophone might be sold under the name "Pan American" or a Buescher stencil saxophone might be sold under the name "Elkhart."
Stencil saxophones were typically less expensive than the top-of-the-line instruments produced by the original manufacturer, but they were still made to a high standard and could be great instruments in their own right. In fact, some musicians prefer stencil saxophones because they have a unique character and sound that is different from the standard models produced by the major manufacturers. However, identifying and evaluating stencil saxophones can be tricky, as the branding and quality can vary widely depending on the specific instrument and manufacturer.