I found this in a auto parts store that had a machine shop in it. So I'm guessing that it's automotive related.  The plate part is about 4" across.  I have no idea what it is.  I listed this here before and no one knew what it was.  So I thought that I would try it again. There are no name or numbers on it.
I have no idea what it could be.  I would appreciate your thoughts.
Both sides look the same.

It reminds me of a damper in a chimney but we know that can't be right. How thick is it ? is it one or two plates making up the circle? are the threads imperial or metric. A few more pics may help.

Could it be used to stretch some sort of material over a cylindrical form?

How about a photo of the other side?

How about a photo of the inside?

Could it be a mould?