That's the drum. I got it from Bobby.
So, if anyone else has information about the mechanism, particularly with respect to the end fixity of the internal rod, it would be very helpful to know.
What I find so far, as seen in the pictures Stallwart kindly provided, is that one end of the rod is threaded and onto it is fitted a piece that was bored and threaded then machined to have a wrench end used to move it back and forth along the threaded rod. Then a flair was fashioned on the opposite end that makes contact with a partially concaved, partially flat washer that is slotted to allow it to pass onto the rod. There is a bushing between the shell and that washer. This entire arrangement allows the machined and threaded piece to become the means of tightening the rod to the proper operational condition. The first picture illustrates this close up.
However, there is nothing on the opposite end and the rod is not threaded so it is obvious that keeping the rod centered was not originally achieved in the same way. It appears the rod needs to be centered because it is not properly driving the butt end mechanism - moves in a cam like direction and the cutout in the shell seems to indicate there was something there at one time. See the second attached picture.
I'm going to proceed to disassemble the entire mechanism to see if I can discern how it is supposed to operate overall. It could be that the butt end needs to be cleaned and that, that end is supposed to move in a cam like fashion because that is how it is driven up or down.
Again, any information you have from either a 701 or 99 Super will be appreciated.