Hi!  The Mira sound post was a wooden threaded rod about 5/8-inch
in diameter.  On the bottom was a base that looked like an up-side-
down saucer, with a hole in the center for the rod.  On top was
a wide threaded nut (round) that could be adjusted to tighten it
up against the bedplate.

I'm sorry I don't have a picture of it for you and I hope you can
picture what I've described.  Feel free to call or write if you
have any questions.  I have quite a few discs for that machine, if
you need any.

Enjoy the summer!

Nancy Fratti - Nancy Fratti Music Boxes
Canastota, New York, USA
http://www.nancyfrattimusicboxes.com/