Brian and Greg: There is no lock nut on the shaft. The photo shows the shaft that needs to be replaced. On the right-hand end of the shaft, it goes through a plate and on the other side, at the end of the shaft there is a 1/4" square that fits into the damper bar such that when you turn the shaft it turns the damper bar which then lifts up the damper. It is the most screwball design and is actually designed and constructed backwards from what it
should be. Totally stupid.
But my problem still revolves around how to remove the shaft in the photo above. It appears to
thread into something through the plate, but after soaking for two days and banging and heating I still have not made a dent in making this piece move at all. If I knew how it went in, I would be able to get it out in a flash. The shaft is shaped like a "Z" when it goes through the plate and connects to the damper bar. The shaft must have to remove from the "Z" portion or the shaft could never go into its location.
Here are a couple of more pics.