The pendulum and it's suspension assembly was missing when I acquired the movement. The
fabricator did a beautiful job of blending the design of the pendulum assembly to the
design of the movement. There were several special challenges to this design since it had
to swing behind the dial. It had to have two "key holes" in it's rod to
accommodate the cannon pinion holding the dial hands as well as the going train winding
square. I had decided on a bob constructed from dual glass jars to hold mercury.
The first two drawings show the design of the pendulum rod against that of
the going train frame. Efforts were made to make the design of the pendulum look as if it
was a part of the original design.
Shown are the pendulum as well as the bell support frame mockups in
brass-painted wood. At this point the bell pulls are not
yet in their final design iteration their levers still outside the frame.
Overall look of the clock on mockup stand, weights and pendulum assembly.
Original pendulum bob design. This was later changed to avoid the use of a
threaded ring that was glued to the glass upon which the lids would screw down.
total volume used for mercury at 4/5ths level is 640 ml - about 9.1 kilos or 20 lb of
First wooden mockup of the bob using the thumbprint jars provided
Final product. Here the threaded rings glued to the glass are eliminated.
The lids (with a leather gaskets) now rest upon the top of the glass jars and are pinned
into place with the pair of four-armed handles attached to threaded screws. When loosened,
the entire assembly swings away supported by the side rods attached to the lower pivots.
center knurled nut is for fine adjustment, a scale delineated in seconds/day will be
mounted behind this. The nut below is for coarse adjustments. Upon reflection, the fine
adjustment should have been done in the conventional manner through the upper suspension
mount, thus being able to do this without stopping the pendulum.
jars are shown filled with tungsten powder to simulate mercury. Upon
delivery the two jars were filled with 10 lbs. of mercury into each jar.
Early wood mockup of pendulum support system. Notice the consistent use of
curvilinear design for the new pieces to match the old. The parts are
then spray painted to match the extant brass parts. We used this method
extensively in the next project I enlisted the Buchanan firm in,
Final support. Adjustments have been included for left to right and front