To me the beauty and significance of this clock
lay not only in its unique design and its embrace of the complexity of the
levers and wheels trains contained within, but its ability to fascinate and
inform the observer through its operations. To me restoring this
movement means bringing it back to its full awakening to new life. Without
the restoration of the missing parts it would still be a valuable
horological artifact. But its soul would be absent like a stuffed bird on
the wall compared to others on the wing.
I have asked Buchanan to provide
what I call a 'forensic' report. That is to record his observations as he
goes along. I will provide the .MP3
audio file for each segment but just
in case your security settings will not allow you to open this file I have
also transcribed each session. My additional comments will be inserted into
the text from time to time and this will be in red
text. Buchanan refers to each photo by the number of that photo which
can be followed by each photo above the captioned text. The .mp3 audio file
will appear at the beginning of the
photo sequence in
blue text. Click on this text
and you can then follow along with the audio file by scrolling downward
through the photos as they are narrated one by one in the voice of the
photo shows the initial fly cutting of the index wheel. The second photo
shows the index wheel fitted to existing pawl designed to hold the wheel
stationary until the next fifth day feed. The last three photos show the
assembly mounted within the existing clock’s structure. It fits neatly
between the two drop down frames. The five cams which control nearly the
entire left hand wall of the clock as well as the mystery dial are mounted
to this arbor. The wheel has 73 teeth and is driven once every five days for
one revolution in 365 days, (73 x 5 = 365). This wheel is the drive for the
cam pack that will be attached to the arbor.
Photo 21 002.
This is the operating mechanism for the sunrise/sunset dial. The two black
levers horizontally in the photograph are the teeter-totter levers. The
point of this photograph is to show at the right hand end of these two
levers we can see the bluing has been rubbed off by the operating cams
(witness marks). And it also gives us the
position of the cams on the missing one year arbor
(the arbor that will hold the cam
pack assembly). Interesting to note is the
little counterbalance weight on the length of day and length of night lever.
The round rod in the center, it has been plated but the radius on each end
have obviously machined away the plating.
Photo 21 005. This is another
view of the teeter-totter mechanism for the sunrise/sunset shutters. What
we’re trying to show in this photograph are the four pins roughly in the
center of the photo with the ridge in the middle which are, I believe,
spring anchorage points to maintain contact between the lever and the cams
that are missing.
Photo 21 006.
These are the four cam blanks. They are discolored
due to annealing, as they, obviously,
will be fairly delicate items by the time they are finished and in the
foreground is the lever mechanism, for the day/night length and
These cams will
later hardened before installation.
Photo 21 008. Here we have a
view from the front of the clock just below the orrery platform. And I’m
trying to measure the gap between the lever for the sunrise/sunset shutter
which you can see on the left hand side of the picture and the one year
arbor to establish the maximum diameter for the operating cam.
Photo 21 009.
This is obviously the front view of the mystery dial for the equation of
time. Of interest to note which I will point out again in later photographs
is the central decoration pattern in the center of the dial which serves to
hide the extremely small 12:1 ratio gear box. If you look very carefully at
the 35-40 minute position you can just see a few teeth of the 12:1 motion
work projecting just outside of the pattern in the center of the dial. These
discs are plastic. We later
determined them to be glass. The question has
been raised as to whether this is also an add-on as the tellurian or whether
this is a full-on Pouvillon complication. And at present my opinion is most
of this is Pouvillon original, although as we progress in the photos, there
are certain components, I believe, he has borrowed from pocket watches. The
surround to the dial, the engraving is very typical of engraving on other
parts of the clock. This leads me to believe that it is Pouvillon work.
Photo 21 010. This is the center
of the picture, is the star wheel that revolves once a year obviously still
to be spoked in the distinctive pattern that we can see in the
photograph of the clock in its original form. This is a blow up
from the first photo in
the Miclet article.
This is the upper surface of the orrery support plate. It is, if fact,
mostly covered by the actual base plate for the orrery itself. Of interest
to note is that there are a number of screws projecting though the plate and
also the cutouts clear projections below the main orrery plate. We can also
see a stoned finish on this plate and I’m wondering whether it would be in
order to maintain this finish as an
original finish as opposed to other surfaces which are completely polished.
Photo 21 014. This is a back
view of the mystery dial; the equation of time dial. The ring that retains
the plastic centers is not plated while the rest of the construction all
appears to be gilded. You can see in the center of the rear stationary
plastic disc the support pivot for the mystery dial as well as vertically
above it just projecting from the rim we can just see the extremely small
12:1 motion work.
Photo 21 015.
We have the support tube removed from the main mystery dial.
Photo 21 016. Of interest are
the cut off screws without finished ends on the end of the support bracket.
And also a little bit of bad finishing work on the actual flange itself on
the left hand corner.
Photo 21 017
is a view from below showing the drive mechanism to the mystery dial we have
an arbor cross-wise in the hole. From the left hand side is a bevel gear.
The black dot in the center is the pivot for the driving bevel, obviously,
which is removed. And on the right hand side is the gear that drives a very
small pinion further inside the mechanism.
Photo 21 018
is a close up of the 12:1 ratio gear just visible in the center. As I’ve
said before an extremely fine gear for something of this size. We can also
see deterioration of the printing of the hand on the plastic dial this is
going to be a conservation problem.
Photo 21 019. We have the plastic
disc that drives the hand and its driving gear at the bottom of the picture.
And in the front of it we can see the six toothed pinion that is driven from
inside the base. Photo 21 020.
We have the rear support plate or the back plate of the mystery dial removed
and we can see the driven gear and the driver gear below. Also of interest
to note are the center punch marks on the plate.
Photo 21 021.
We have the little front plate removed and we can see more of the driving
mechanism. Photo 21 022. A
closer picture of the bridge supporting the drive arbor.
Photo 21 023.
A close up of the gear and pinion that actually drives the mystery dial.
Both the larger gear and the pinion appear to be modified pocket watch
Photo 21 024.
Another view of the driving gear and pinion. And we have a little brass bush
just visible between the gear and the actual pinion which leads me to
believe that this was a pocket watch winding gear added to a pocket watch
pinion and the brass bush is an adaptor to make the two together into one
component. It wouldn’t be normal pocket watch construction or if one were
making this component from scratch for one’s self, the pinion would be made
a press-fit into the gear as on most pocket watches.
Here we begin to see the
small handful of components Pouvillon used from other sources to build the
mystery dial internal components.
Photo 21 025.
The intermediate drive gear and arbor removed from the mystery dial. We see
a bevel wheel drive which appears to be very similar to a pocket watch
winding gear or winding bevel. And also, I believe, an adaptor collet at the
back with a very standard Pouvillon style of grub screw to lock it onto this
arbor. This is required because unless one has the bevel gear separate from
this arbor you can’t remove the arbor from the little bridge plate.
Photo 21 026.
We have another view of the intermediate drive arbor and the bevel with the
brass bush and the grub screw that I believe is a modification.
Photo 21 027.
A front view of the intermediate arbor and showing the gear wheel which I
believe is borrowed from a pocket watch or cannibalized. It doesn’t bear the
standard Pouvillon stamp
(style) and appears very much to be very much a
standard pocket watch component.
Photo 21 029. We have a view from the other side of the intermediate
gear showing again what I believe to be typical pocket watch style where we
have small bevels on the spokes also the riveting; not common to other
components in the Pouvillon clock.
Photo 21 030.
Here I have the complete drive train to the mystery dial assembled without
any external components. So we have the glass tube that would come from the
main time drive with the little bevel cemented into the tube; driving below
it the bevel on the intermediate arbor. Then we have the brass gear in the
foreground meshing with the little six tooth pinion in the actual bezel of
the mystery dial and that itself again driving the larger steel gear which
drives on the rim of the mystery dial. The
gearing is arranged so that one revolution of the glass tube gives us one
hour or one revolution of the driven disk in the mystery dial
(upon which is mounted the minute hand).
Photo 21 031.
Just a close up of the bevel gear drive using, I believe, winding bevels
from a pocket watch. This is also substantiated by the fact that we have a
compound bevel gear. Where we have a bevel with a cylindrical gear machined
out of one which performs in a pocket watch two functions. And here it is
used only in a single function. The compound bevel
has a specially designed tooth profile that allows it to properly mesh as a
bevel gear set and to be able to drive a wheel with a normal toothed
profile. This arrangement would commonly be found the winding stem in a
pocket watch where the stem is at a 900 angle to the plane of the
watch train and so is geared through a bevel gear set to transfer the feed
from the stem to the watch. At this point a conventionally toothed wheel
carries the feed to wind the mainspring.
Photo 21 033.
A close up view of a screw that attaches a bridge inside the mystery dial.
It appears to be borrowed from a watch, not one of Pouvillon’s standard type
screws. Again reinforcing a little the fact that he was using components
that came to hand whenever possible or whenever it suited him.
We will see as we go along
that Pouvillon’s use of other parts is fairly limited, with the exception of
the tellurian. They are largely confined within the mystery dial. In this
component we have some of the smallest wheels and other components that will
be encountered in the clock and it is possible that Pouvillon was equipped
to make parts on the scale of a clock, but not a watch. Or he was simply
opportunistic and took these small and unobtrusive parts wherever they
served satisfactorily to save time and effort.
The remaining four photos show the
step wheel and the four blank cams, (the cam pack), installed into the
movement. You can see there is a bit of room still open on the left end of
the arbor. There is yet to be one more cam to be fitted in this area in
connection with the Easter calculator. The cam pack is the one major
component that was lost on the clock quite early on after the death of Mr.
Pouvillon in 1969 since we know from other photos taken in 1983 that this
component was already missing.
Photo 23 001.
He we are marking out the one year wheel for the equation of time cam arbor.
As you can see we have a steel movable bar which we can adjust the inner and
outer center to obtain any thickness or taper of spoke. And you can see the
little arrow-shaped clamp in the vertical slot in the jig plate which serves
to clamp any wheel that we want to work on.
Photo 23 002. Here we have the
marking out of the year step-feed wheel practically complete and the holes
drilled for the piercing saw blade to enter in each section.
Photo 23 003.
As you can see the piercing of the gear blank is in process. We have an
extra brass disc with a narrow slot below the blade to prevent distortion
which occurs if you use a support disc with too large a gap. If the tooth of
the saw catches an unsupported spoke and here we’re working with spokes less
than a millimeter wide and the stock is only about 1.1 millimeters thick. It
can quite easily badly distort the spoke if the blade catches it at all.
Photo 23 004.
Just a slightly enlarged view of the Hegner scroll saw I use as well as the
binocular microscope which facilitates cutting accurately to the line.
Photo 23 007.
Here we have the completely pierced wheel and all the waste that came out of
it. Photo 23 009. The completed
wheel on its arbor the spokes have been filed. We have introduced a little
taper to the parallel spokes as when finally cut out the spokes, each
individual spoke, was parallel and they looked heavy towards the end so we
introduced the taper to give a more balanced look.
It is impossible to know if Pouvillon had introduced this refinement in his
original step wheel because the old black and white photo from which we took
the design from does not have the resolution to determine this.
However this is
quite possible as it is quite likely Pouvillon drew the inspiration for this
wheel design from prior makers. An example from an orrery clock by Zacharie
Raingo, c. 1810 is shown below. This example has a bit more of a taper to
Photo 23 010
is the one year arbor fitted below the orrery platform with the one year
drive wheel mounted and the four cam blanks. The smallest is for the length
of day length of night indicator mechanism. The next two, equal sized, are
for the sunrise/sunset dials (actually the shutters
not a dial) and the fourth one, you will see we already have reduced
the thickness from 1.6mm to 1.2mm is for the equation of time dial.
This cam had to be thinned in order to fit between
the two guide whiskers present on the equation cam following lever.
Photo 23 011. We have a full
front on view of the four cams on the one year arbor. In the upper left of
the photograph we can see the two blued levers that go from the two center
cams out to the sunrise/sunset shutters which you can just see in the bottom
left hand corner behind the sun hand. The sun hand rotates once in twenty
four hours. This is fed from the main time train. The cascade of gears
downwards from the sun hand arbor and the actual one year arbor is driven
from the strike train and is stepped once in twenty four hours via yet
another 1:5 step down ratio. So that the one year arbor actually only moves
once in five days, seventy three times a year. This
is why that wheel has seventy three teeth; 73 times 5 equals 365.
two photos show how Buchanan was able to use the extant parts of the clock;
specifically the four dial input levers for the equation of time, sun/rise
sunset shutters and length of day/length of night dials to accurately locate
and shape the cam pack.
The first photo
is a section of the only overall profile photo we have of the clock taken
before the death of Pouvillon in 1969. This was the only visual source of
information we had to go on for the design of the step wheel. It was very
fortunate as there was no way we could have guessed at the wheel’s
decorative design which is not replicated anywhere else in the movement. The
remaining components attached to this wheel’s arbor, the cam pack, we were
able to deduce from the components which derive their information from these
cams. This information gives us the profiles of the cam’s perimeters, but
not any information as to how Pouvillon would have spoked these.
23 013. This is a view of the new one year wheel fitted to the clock.
I’ve tried to take a photograph from as close to the same angle as in the
original Pouvillon photograph to compare the proportions of the wheel. And
it’s quite interesting how closely we have managed to find this.
Photo 23 017.
shown) Another photograph of the one
year wheel fitted to the movement. I’m trying to check out the perspective
and see how closely we’ve managed to copy the original missing gear.
Here Buchanan uses a pair of cam calipers to help
in taking the measurements needed to determine the cam profiles.