Fabricate dial support latches, polish equation and time transfer
trains, tripartite drive, escape wheel assembly, rack let-down flies, orrery
Buchanan continues the final phase of the project, the refining and
polishing of all components. In this installment the fabrication of bezel
support latches are made for the tellurion and mean time dials and an
improvement in the strike detents. Finished are the time transfer and
equation of time trains, the tripartite drive for the calendar, sidereal and
equation trains, the escape wheels and anti-friction wheel support structure,
the strike detent and rack set-up a flies, and part of the orrery drive.
In these photos one can see the occasional use of CAD-CAM used on the
project. This is used when there are multiple identical parts, which has
seldom occured. In this instance Buchanan is cutting the dial latches.
is an example of some of the remaining fabrication work needed on the machine.
Buchanan has made a set of quick release latches for the mean time and
tellurion dial bezel support
The first photo is the mean time dial from behind and one can see where it
attaches to a pair of pillars one of which holds the tripartite drive off to
the left, (more on this later in the segment). The second photo has the
tellurion transfer wheel, but the dial ring will pull away while the
transfer wheel stays attached to the clock frame.
The pillars are now shown after decorative turning and all the parts are
Equation of Time Differential
Shoen above are the wheels and cam follower arm.
The equation cam follower arm is shown above. It has a jewel bearing set
into a steel rim. The follower recently had a bias spring installed to
ensure it remains seated on the equation cam. Next the frame pillars are
The completed equation of time differential wheel works, less the cam
follower (left), as compared when it was first fabricated in
The completed equation of time differential.
Equation differential wheel train parts, 121, total to date: 1820.
The tripartite drive is a combination of three drives from one source, for
the calendar, sidereal and equation of time complications. This was first
begun in September 2014.
These two photos show the frame with
pillars now turned. The pair of curved parts that look like insect mandibles
are jewelled pivots for two drives aimed at complex angles. Although it may
look like Buchanan simply took a pair of pliers to twist the metal to this
shape, in reality these are much too thick to do this and they were cut by
hand with a piecing
saw from a solid block of brass. The curve of each potence had to be
precisely shaped to ensure the pivot jewels mounted at the end of each curve
had their holes aligned perfectly parallel to the two arbor pivots that must
fit there. The first photo certainly evokes the analogue of an insect with a
pair of antenna tipped with red spots coming from behind the jewel chaton head and
a pair of mandibles below; although this insect only has four as opposed to
the requisite six legs.
A sample of the complex turning of the frame pillars.
Next most of the wheel components for the drive.
The first photo shows conventional way many clockmakers would approach the
need for two different diameter wheels spaced closely and fixed on one
arbor, by sandwiching one on top of the other. The next wheel in interesting, Here we have not only two wheels of
differing diameter but the inner also being a bevel. Again it could have
been done as the other two, but the depth clearance was critical and there
was not enough space for a sandwiching of two separate wheels. So here
Buchanan makes both wheels from a single brass blank effectively
countersinking the smaller wheel into the larger. Even here Buchanan
keeps the spokes thin, in fact if you were to measure the width of the spoke
from the hub to rim, it has the same taper as if there were no second bevel
wheel in the middle.
First photo shows
the wheels installed on the front frame and next the frames completed, it
also shows the component from the outside with the demonstration dial
mount and gives the viewer the comparative size of this component.
Pictured above is the completed tripartite distribution system which feeds
three separate complications. The equation drive requires one
revolution per year, the sidereal drive two revolutions per year, and the
calendar drive one revolution in 24 hours.
Notice the small decorative turning in the
middle of the calendar drive arbor. This is a view as it would be seen from
the inside of the machine. From the outside the photo would be flipped about
its horizontal axis.
This video was taken in May 2020 during the final polishing and assembly
procedures of the machine.
distribution drive 80 parts, total to date: 1900.
Time Transfer Train
In conventional clockwork the time, quarter and hour strike trains are close
enough together that communication between the trains can be accomplished
through levers comprising the strike work linkages. In this clock the time
train is located on the left side of the clock base with the strike trains
located at the opposite end and the celestial train located between. The
time transfer train is needed to bridge the gap occupied by the celestial
train; enabling the time train to synchronize to the strike train's snail
cams. It is a set of
idler wheels designed to look complex and beautiful. One could have used a
row of wheels that were all the same size but the style of fabrication used
throughout this project is what we call "Buchananization" which calls for an
interesting presentation and making wheelwork that fills all the available
space to make what is already a complex machine appear even more so. This
was first fabricated in
October 2010. The machine looked quite different back then.
Compliment of parts for the time transfer train, less some parts: jewels, screws and
The first photo shows a red, plastic ring made to look like a jewel,
behind this is a ceramic ball bearing holding the tellurion transfer wheel.
The next photo shows a true jewel pivot for each time transfer wheel.
To keep the time transfer train looking as light as possible the wheels run
on only one frame instead of between a pair as would be expected in a
conventional design. The way to achieve this is to run the wheels on arbors
attached at one end to the face of the frame and with the taper hole on the
other end to secure the wheel; these are referred to as 'dumb arbors', first
Completed time transfer train which runs along the rear side of the
clock. The wheels all run on just one frame to make this look as light as
possible; like buds or flowers on an ivy vine.
This in keeping with our
organic design theme throughout the machine exemplified by the main frames
to look like trees holding red fruit of ruby colored pivots surrounding a
forest of wheels interspersed by curvy ivy shaped parts. Bird analogues
inhabit the forest, and in the firmament above is the Sun Moon and planets
of the orrery.
Parts count for the time transfer train, 69, tellurian transfer train, 17,
total to date: 2003.
Escapement Wheel Pair and Support Assembly
The escapement assembly as many other components in the clock is very
different from conventional clockwork. The escapement is not located in the
time train but in the celestial train. The reason for this is, again, for
visual presentation. To have the escapement be directly in the middle of the
clock, it must be located where the celestial train is located. As the
strike trains must be coordinated with the time train remotely, the
escapement is driven by the time train through a long pair of arbors that
reach across the space between the time train and where the escapement
assembly is located. The escapement wheel assembly consists of a pair of
counter rotating escapement wheels and the compliment of antifriction wheels
that support it; also on the same frame because of its location, is a small wheel
set that connects to the orrery drive. Fabrication began in
These parts comprise
the anti-friction wheel support assembly for the escape wheel pair.
The eight ant-friction wheels are shown in the first photo with their
support frames emphasizing the jewel chatons.
This is a connecting wheel to the orrery drive that is mounted to the
escapement wheel frame due to the proximity needed for this part. Notice
the differing colors of the brass upper wheel to the pink bronze bevel below.
The next photo shows this part on the escapement wheel frame along with an
adjacent set of anti-friction wheels to support the escape wheels pair.
Four photos showing the grasshopper escapement wheels.
This photo shows the
pair of counter rotating grasshopper escapement wheels as well as their two
drive wheels, first fabricated in September of 2008. The execution of the
swirled spoke design for the escape wheels must be one of the more difficult
spoke designs to execute in this project. Look at the inner hoops within the
two drive wheels. These are guide rims that along with another pair of
same-sized hoops will keep the escape wheels in position upon the antifriction wheel
These two photos are the pair of guide
wheels that fit closely between mating hoop rims as illustrated below.
This photo shows how
the escape wheels are held in position upon the antifriction wheels. There
are no pivot holes or arbor shoulders adjacent to those pivots to ensure the
correct positioning of the escape wheel rim in relation to the escapement
pallets as would be found in conventional clockwork. The horizontal guide
wheel pair, (two photos above), fit closely between the inner rims of the
toothed drive bevel wheels and the smooth rimmed wheels opposite. It’s
important to note that there is a very small amount of clearance between the
distance of the two vertical rims and the horizontal guide wheel. Just
enough to ensure proper alignment of the escape wheels with the clock’s
pallets, but not touching both at once which would cause a lock-up of the
escapement. What makes this design interesting is that those guide wheels
will also turn along with the escape wheels making for another interesting
piece of machinery to look at.
Front three-quarter elevation view of the escapement assembly.
Entire escape wheel and support assembly with
additional orrery drive wheel in the back.
Escapement wheel and support assembly 262 parts, total
to date: 2293.
Strike rack let down flies and strike cycle
These birds are the detents that engage the strike fly fan to initiate and
stop the striking sequence.
This photo shows
another ‘housekeeping’ item Buchanan has attended to. These are the pillar
mounts for the strike train detents that take the form of a bird, (photo
above). The fly fans moderate the drop of the quarter and hour strike racks
as they are large and heavy, and give the viewer another pretty thing to
look at as the strike sets up. The pillar on the right is the original
design, on the left Buchanan has added a bias spring and armature that will
engage the bird detent. This ensures positive
locking. Note the "Buchanan logo stamped on the base.
One pillar with the
new bias spring configuration mounted to its cross
In the first photo a
view from the back side showing a jeweled chaton for the bird detent.
The slanted cutout in the frame is to
provide a throughway for an arbor driving the hour strike fly below. Next a view from the top.
A view of the same bird detent as in the first photo
above placed within the machine.
Orrery Output Drive
Parts for the orrery output gearing, fabrication began
in October 2013.
We need the output gearing to perform two functions. The first is to reverse
rotation of the final output shaft to the orrery from that present at the
bevel and contrate drive wheels. The other is to obtain the correct gear
ratio for the orrery. The period must be changed from mean solar to sidereal
time. Parts count for this assembly, 51.