This unique gage is used to check the operating rod angles of bend, including the four bending configurations used for proper operation (this includes "regular" op rod bend and "national match" op rod bend). The gage actually determines "what's wrong" (i.e. handle twisted, tube bent, alignment problem, etc.).
Point of contact is Jim Swartz - the only person alive today who has ever built these gages. Email Jim at: firstname.lastname@example.org for more info. This is an EXTREMELY HARD TO FIND gage! The gage was built from original blueprints recently uncovered after 60+ years.