Hi -- I was visiting MBSI member Jim Feller several years ago, and
he showed me such a clock and said that he had to replace the spiral
posts.

He made these himself by starting with square brass stock, mounting
them in a lathe, and by turning slowly by hand, he twisted the square
stock into the spiral shape.

Unfortunately Jim passed away last year so we can't ask him for more
details.  Perhaps this can be of some help to you.

Marvin Polan

P.S.  If you know of one of these clocks for sale let me know as
I would like to purchase one.