|Steve Stephens wrote:
I don't think sparks from a fan's switch is normal and have not noticed it on my fans. The square headed bolt sounds like it's a "make do" to replace a missing wing screw or it's not what I am thinking it may be. Post some photos so we can see. 1930 was the last year Emersons had brass blades but an older brass blade can be installed on many later Emersons.When you slide the switch it arcs to the contacts creating a spark for a second. If it continues to spark then there definitely is a problem.
This diagram is from c.1937 and, while not exactly like your Emerson, their fans did not change much in the major details. Your fan does not use a capacitor in the base. Your fan has three speeds. Your smaller fan is a single speed.
Some Emerson info: