In 1864 signal corps sergeants wore crossed signal flags on their chevrons. In the following years various other branch insignia were incorporated into chevron designs. The result was became a nightmare for the quartermaster corps. William K. Emerson cataloged some 191 different chevrons and related enlisted grade insignia designs used during the 1902-1920 period. In a 1920 reform seven grades were established and the same chevron design was used by all branches. The various branch distinctions were removed from regulation chevrons and the quartermaster only had to stock seven different chevron types. However, privately purchased chevrons with branch insignia incorporated into the design continued to be manufactured and worn for the next several decades and during the Second World War. Examples from the Air Force are the most common, but other branches also can be found; such as the medical corps, signal corps, and quartermaster corps.