I haven’t tested the switch but out of the 3 I have they all look the same on the one end the spring is attached to the rivet on the other it is held in by what looks like a bump in the porcelain that goes into the centre of the spring .I am not electrically inclined but I think the current would go through the spoon that turns and rubs on the spring as it is insulated from the housing .Maybe Jon G can help on this one .
