Finishing work: Sun / Moon rise set assembly
- November 2017
This month the final detailing is done on the sun/moon rise-set
The glass dial and sun horizon shutters.
This is the initial
trial of the laser etching for the dial. It still needs some refining and
was done at a local sign company, not a specialty shop. The inking of the
numbering also tends to blur a bit around the perimeter of the figures.
We will be using a special inking process that is applied as the laser cuts
the glass to ameliorate the problem.
Buchanan sent to me two
options for the glass dial inscriptions. The first illustration is the
original submission, but we agreed that the italicized script was not as
legible as the second design using a block style. Furthermore, the
references to the Sun are in a script style in this dial, while the Moon is
in a block design, so this also adds to continuity.
A few glass samples
arrived today for the sun horizon shutters; these are shown both laying on a surface and more importantly
off the surface to allow the color to show through transmitted light. We
both agreed that the lighter one was the better choice.
After several attempts,
we were able to locate the right color of glass in the very thin, 1.1 mm
(0.043 inch) stock needed to fit within the tight confines of shutter
mechanism. This was sourced from China. Next the glass is secured
to a thicker scrap glass for cutting in the mill. One can just see the
outline of the semi-circular shutter.
Several pieces are now
complete, first photo. Buchanan will make a few spares in case of breakage. I
had thought that there could be some confusion with the color of the glass
being a sky-blue color even though they are on the lower sector where the
sun will slide behind. A darker
blue or deep purple would have conveyed a nighttime impression, but then the
parts located behind would not be seen. This, in my opinion, was essential
and the main reason why we went with a clear glass main dial as well as
glass for these horizon shutters. I thought that the addition of stars would
impart the right information that these were representing the night time
section of the dial. My original idea was to simply have a set of stars
laser etched onto the glass. These would have shown up as a white frost
against the blue background. But once again Buchanan is ahead of me with a more elegant idea.
The second photo shows a test star made of brass, no bigger than a match
head. Certainly nicer than a flat, etched design!
Instead of brass the stars are cut from sterling silver stock. Judging from the
curvature this piece was used originally to make a dial.
Notice that each star
is unique and are scattered in a random fashion.
The center arbor decorative cover.
The center arbor, first photo, now has a decorative sun cover which is in keeping with
the surrounding dial work indicating the length of day, second photo.
The artwork and mockups for the remaining dials.
The artwork is now
begun for the remaining dial work including that for the sun/moon
complication. We have the hour and minute sidereal
dials, thermometer, strike select, redo of the sunrise/sunset, world
time/demo, differential sector plates and repeat button-two pieces. I hope
enameller in China can accurately match the background white color and
artwork style from the last batch made in June of 2013.
The dial rings are cut and the curved contour is milled on the lathe.
The dials are now complete both in their dimensions as well as the curved
surface to match the existing completed dial set.
The first photo shows the sector plaques for the two variable
differentials in the moon complication as well as the world time/demo dial.
Next photo shows the Projection sector dial mockup positioned where it will
be on the poising weight for the slant wheel. The rest of the brass that
extends past the plaque will later be trimmed to match. Notice the scalloped
edges match the same style as those sector dials used for the pendulums.
It looks like the day
after a confetti party!
The rotating moon indicator.
Now begins the fabrication of the moon. In keeping with using only
natural materials for the planets, moons and sun we chose ebony and mammoth
ivory. An old school pointer was scavenged for the ebony and the ivory is
from the stock purchased in March of 2016 for the Earth globe in the tellurian. The ring in the second
photo is the age of moon indicator.
The fabrication is not straight forward since we have decided to have
the moon’s age dial ring countersunk into the globe. Had we decided on the
easier route of having the ring secured to the surface we could have simply
made a single sphere from two mated hemisphere materials. Instead we have to
make two hemispheres that will join where the ring will reside. First the
ebony and ivory are glued together. But to ensure that there will never be a
problem with these materials separating, an internal structural retaining
ring will be inserted in the interior circular recess, second photo.
The retaining rings are
inserted in the first photo, next the pieces are turned to their correct
proportions before final finishing into a sphere.
Next the edges are
turned to make a countersink for the moon’s age dial ring. The second photo clearly
shows the area where that ring will be.
The age ring is positioned within the rough material. Next
the part is prepared for final spherical turning.
Next the process of making the two
hemispheres and in the last photo the completed moon with its age ring. This
will later be silvered.
Countersinking the ring allowed us to have the maximum diameter moon within
the confines of the opening within the glass dial.
The moon is now mounted
within the dial assembly.
The glass dial is still a plastic mockup at
The variable differential adjustment dial hands and variable
The dial hands are first roughed out by hand filing, in the next photo a comparison
of the filed flat material, upper hand, next to a completed hand that has
had the arrow head chiseled and the shaft tapered to its final form, lower hand.
Each hand is blued the traditional way on a bed of brass filings over
an open flame. The filings spread the heat evenly over the length of the
part and are used when bluing anything larger than a screw.
Here the sickle levers
in the variable differentials begin their final hourglass form. The large
rectangular poising weights are now replaced with small buttons.
This photo shows the completed adjustment dial (later to be silvered),
the dial hand and sickle lever. The knurled knob just off the left side of
the photo is the adjustment knob to set the differential.
The main support stainless steel pillar for the differential assembly now has its decorative
turning and polish. The setting dials are silvered.
The decorative turning and finishing of main frame pillars.
First the finished finished pillar set. Next a blued screw; this electric
blue color is what I am looking to see for the entire compliment of screws.
The pillars are now
installed within the main frame and the unit is ready for reassembly. The
first photo is the front of the main frame and the next from the rear.
Reassembly of the sun/moon rise-set complication.
differential unit is now fitted to the rear of main frame.
poising weight for the Great Anomaly differential is now trimmed to match
The dial subassembly is
now fitted to the front of the main frame and the completed assembly shown in a front
three-quarter elevation. The only piece yet to be done is the engraved glass
dial and bezel. Then the addition of an enamel dial. There are approximately
550 parts, about the same as the perpetual calendar which sits to the left
on the movement.
Front elevation. Can you see the sun rise shutter
cam looking like Mr. Sun giving a
"Peek-a-boo" from behind the outer rim of the main dial?
The assembly now crowns the
upper right quadrant of the machine and largely fills the area across the top
of the bell works.
Here the reworked outer
bezel mock up and inner enamel dial are installed.
Only the glass dial,
awaiting laser etching is yet to be attached.
Notice in the first video the starting positions of the variable
differential slant wheels, where they begin roughly at the same angle; with
the two anomaly identification plaques similarly aligned and how they move in
relation to each other and the ending where they are at opposition. In other
words the precession of the differentials varies in relation to each other.
In the second video one can see the movement of the sun horizon
shutters in relation to the change of the seasons as seen by the movement of
the Earth globe below. Does this look wrong? Why in December are the
shutters approaching their lowest level, indicating the longest day? Well
this clock is still in Australia! Of course all of the celestial functions
will be corrected for the latitude of the clock's permanent location.