Skeletonize calendar frames, other misc. items
- June 2015
The photos below show the
final steps in pinning the various levers and cams to their collets. This is
a very tedious process. Every part must be perfectly positioned not only in
relation to the rest of the surrounding parts on that same arbor which may
contain several collets; each with its own lever, but also in relation to
the type and strength of the various tensioning springs used throughout the
calendar and how those components interact with their neighboring parts.
With the exception of the bevel wheel drive
to the year counter, the entire calendar assembly can be disassembled and
reassembled without regard to the positioning of adjacent components. There
is no need for the synchronization of wheels, pinions and cams. The fact
that Buchanan has taken the time to
attach all of the cams and levers to their arbors with taper pins instead of
allowing for later individual adjusting means that there is no apriority
knowledge necessary of how the computer must operate. This is extremely
important since the likelihood of anyone having this knowledge many years
from now is slim. It should be noted that to fabricate the calendar in this
way is much more difficult than to have had it made with the parts allowed
to be adjusted upon their various arbors. Everything had to be perfectly
aligned; the entire calculating operations debugged, checked and double
checked before being permanently pinned.
I was concerned about
the possibility of there being problems with adjustments of this device and
Buchanan said that pinning, while very difficult to set up was the most
stable way to make a complex set of levers as might otherwise be found in a
quarter or minute repeater strike train. Our grande sonnerie, pull-repeat
system comes to mind. It would be easier to make all of the levers with
small adjustments allowing them to be moved in relation to each other, but
as one can imagine, this opens the door to them coming out of adjustment.
Unlike even a minute repeater mechanism of which there was many
prior examples to refer to, this is a unique device. We do not think a
reversible; third-order perpetual calendar has ever been made before so
there would be no reference examples. Additionally this is as complex as a
repeater. There are about 550
parts that comprise the entire calendar mechanism. Later we found that we
also needed lever stops to keep the various levers from flopping out of
position if the calendar mechanism was removed from the rest of the machine
and turned sideways or upside-down. This is another unlikely scenario but
one which we will ‘over-engineer’ for. Given the extreme complexity of this
machine we have no other option but to over-engineer for every contingency;
not unlike the methodology NASA uses in their space vehicles.
Here Buchanan is using
the EDM machine to make the smallest taper holes for the pinning of the
levers on their respective arbors. The diameter of the holes needed, (6.5
thousands of an inch), as well as the fact that the arbors have been
hardened makes this too difficult to do with a conventional drill. A thin
wire is soldered to a thicker holder which is then held in the lathe and
spun between two fingers to make it straight and true. That wire is then
connected to the copper electrode of the EDM machine, red arrow.
These photos show other
various parts that have larger taper holes made in the conventional way. The
last photo shows a very narrow five sided watchmaker’s broach used to give
the parallel hole drilled by a conventional twist drill a tapered profile.
It is spun very slowly in the lathe as it cuts the proper profile. This is
what was done on the very best movements made in the past. For those who are
reading this and have had experience working on clock movements, how many
times have you suspected that the hole that has a taper pin is merely a
straight sided, conventionally drilled hole? Did that pin go in the same
distance when inserted in either end? Yes? Then the hole was not tapered. A
properly tapered hole will allow that pin to go in further in one direction
than the other. Furthermore, it simply ‘feels right’ when the pin inserted
into a properly mating tapered hole.
Here I show a small
adjustment problem where two adjacent levers are rubbing against each other.
I point this out since this is exemplary of the countless number of
instances that Buchanan has had to deal with these types a ‘bugs’.
Notice the beautiful delicacy of the spoke and rim connection of the
crenulated wheel in the lower right hand corner.
Next we discussed again
how the calendar would be adjusted including the perpetual module, shown
above. Basically the perpetual module has two sub-components that sit one on
top of the other and which can be independently adjusted. Buchanan suggested
installing a knurled knob just behind the readout hand for the date on the
perpetual module and this will turn the outer sub-component, left hand
component in photo. Turning this by one revolution will advance the 20 year
cam. So five turns of the knob will click over the 100 year cam which is
located just below the 400 year cam and this will advance that cam one
quarter turn. This is done while the readout detent is engaged and holds the
inner subcomponent stationary. The month tracking ring resides in the inner
sub-component and this can be adjusted by lifting the readout detent and
then simply spinning the readout hand. This will rotate the entire module.
(See video later in this segment).
Here the small indicator hand for the 20 year cam is
fabricated. Next the rim of the perpetual calendar module is drilled to
accept that hand.
Here the hand and where it is attached is shown. The
third photo shows the knurl knob fabricated to manually adjust this portion
of the perpetual calendar module.
The knurl adjustment knob is attached to the calendar
module and is shown in place in the third photo.
The video shows the two-step process to set the perpetual
calendar date module. The first is where one uses the center knurl knob to
spin the twenty year cam one revolution per turn of the knob, so 100
years is five turns, and if the clock were to lay dormant for 400 years then
20 turns would fully rotate the 400 year cam. Next rotating the entire
assembly by the indicator hand while the calendar detent is disengaged, as
is shown next will set the module to the correct month internally. Twelve
turns comprises all of the possible months. These steps can be done in
either forward or reverse. Notice how small the perpetual date module is.
The upper and lower bevel drive wheels are now
installed and this completes the connection of the calendar remontoire drive
to the rest of the celestial train.
The calendar unit appears to have filled in quite
Below are several videos showing the completed calendar
system under test.
In these videos the calendar is stepped forward and
then in reverse in real time by manually winding the remontoire that powers
this system once daily. The remontoire under normal operating conditions is
wound in very small increments and slowly throughout the day. Under the demo
it is wound more quickly, within seconds, and thus one sees a bit movement
in the system before the works are released and the calculations take place.
The speed at which the components move is the actual speed as driven by the
remontoire and will take place at midnight daily.
In the first video we see the calendar operating at
maximum speed. This would be achieved only while the operator is cranking
the celestial demonstration key on the machine at maximum speed. The
calendar system is equipped with an 'over speed' safety clutch system to
prevent damage to the remontoire and possibly the rest of the calendar
mechanism from being overdriven.
In the second video we see how the celestial drive will
be cranked by the machine's operator and the results within the calendar
assembly. Notice how the hands also move with the demo crank. These are our
world time dial hands. This dial shows the time at a few other cities in the
world. But it also serves to allow us to bring back our demonstration once
completed, back to within about ten minutes of where it began no matter how
many years forward or reverse we go. The calendar allows us to see where we
need to be to within a day. A ten minute accuracy is more than sufficient at
the scales represented by celestial functions. Notice how the rest of the
clock appears to alive and breathing during this demonstration.
Buchanan now begins to skeletonize the calendar
The front and rear main
frames as well as a smaller sub frame are seen in the first photo along with
scanned images. Next he front dial plate is shown mounted to the machine.
We see here the process
used to design the decorative features for the plates. The open book has a
detailed photo of the back side of an antique pocket watch showing the fancy,
skeletonized balance cock. The initial
design begins to germinate in the drawing in the lower left.
The next drawing shows where all the current pivot and pillar holes are
The object in the center is an outline of
the front pillar of the time train to which the calendar is affixed.Here is where ideas are imagined.
The first drawing is the same as that shown
on the table above. The initial design begins to take shape with simple
curves that attempt to engage with as many of the hole locations as possible
without contorting the curvilinear design. Next those lines have been decorated into the organic ivy and
spur design used throughout this project.
Here is where imagination meets artistry.
Now the fun begins!
Once more Buchanan employs the trusty jeweler’s saw equipped with binoculars
to delicately pierce the brass sheet and create his ornate design. The same
saw that has cut all of the flat stock, from frames to many hundreds of
wheel spokes on this project. One can see the inspiration of a pocket watch
balance cock on this piece.
decoration for the rear main frame.
All of the ivy appears to be growing just like a real plant from a location
at the 10 o’clock position from the center hub. There will be further hand filing and
refining of the entire piece. A bit of explanation here is in order
regarding the nomenclature used between what is called a plate and a frame.
A conventional solid piece of brass used to hold the wheelworks of
conventional clock work is called a plate. This type of movement is usually
found in a cased clock made of any variety of materials ranging from wood to
stone and where that clockwork assembly is never seen since it is hidden
with the case. In a skeleton clock, or a clockwork movement that is not
cased and is specifically made to be seen as an exposed entity and where
that movement’s plates are decorated, usually by the process of piercing, or
the cutting out of the plate into a fanciful design, the name is changed
from a plate to a frame. This is appropriate since in conventional clockwork
what holds the clock’s wheel works are indeed solid plates, but in a
skeleton clock the plates become the “frame” which holds the wheel works
within, not unlike a beautiful picture frame holds a painting.
Here artistry is made real through hand-crafted
The front frame also will serve as the mount for
the enamel dials and their bezels. Unlike the rear frame, where one could
draw the curvilinear lines to catch all of the pivot holes, here we are
constrained by the outlines of the dial rings. Consequently, there are a few
pivots caught by small ivy ‘growing’ from two of the dials as well as
several ‘buds’ around their perimeters; once the dial bezels are in place
those buds will nearly disappear.
In the first video the operator cranks the demonstration handle four turns
to fully wind the remontoire spring. The mechanism is then tripped to power
the calendar functions. In this video none of the internal levers
representing the logic components are present. The right hand fly fan would
be turning if the demo crank were being turned in the opposite direction. In
the second video
we see the complexity of the calendar mechanism
upon the backdrop of the fretted out back frame.
The calendar now reassembled. Front view. Buchanan's
hand gives one a sense of scale.
Here hand-crafted machining skills result in a beautiful piece of
Rear view showing the triple frames that encompass the
main calendar mechanism in front as well as the remontoire and overrun safety clutch
to the lower rear of the assembly.
Rear, upper three-quarter view.
In this photo the front frame has the cutouts for the
dial work. The dial rings appear to be a bit larger wider than one might
like, but later it will be seen that when the enamel dials and their bezels
are mounted they not appear to be too wide.
Rear three quarter view.
All of the behind-the-dial work has filled out that
The closely packed components. Here kinetic
art is made manifest in this complex, fantasy machine.