Complete finishing of the calendar module -
This month Buchanan completes the finishing of the calendar module. We have provided a video that should
please even the most "hard core" gear -head, be sure to view it at
the end of this
The first photo shows the parts finished, the second parts yet to be done.
First photo shows the three main drivers for the logic levers. The
ends with the leaf springs are moved by the rotating timing logic cams in
the calendar trip area (see last month’s installment). Next show the
beginning of the jewelling of the digital year readout. This is part of the
debugging process. The gears that drive the the digital wheels as well as
the wheels themselves required jewelling for less frictional rotation. The
second photo shows the jewels as they came from the supplier with a smaller,
resized jewel that Buchanan has made for this application, reducing the
original diameter of 3.0 mm to 1.5 mm.
The additional fifteen jewels are shown with the parts ready for them in the
first photo, next a comparison of a cog count wheel with a jewel on the
left, and with the original design on the right.
This photo above
beautifully illustrates Buchanan's fretwork, the curvilinear style, sharp
ivy tips. Note the tiny pair of holes barely held by a drooping ivy tip just
to the left of the center disk.
The wheel used as a
detent on the star cam wheel is actually a left-over part from our original
escapement design in January 2009. That escapement had four of these wheels
and was eventually was scraped for a better design. It was one of the very
few times Buchanan had gone down a blind design alley. Waste not want not!
Another view of the wheel and star cam controlling the
flip of the digital display. Next a close up of the year display clutch
controller. This operates once per year to activate the year counter.
begins the finishing of the calendar calculator cam module, the processing
and storage components of the analog computer that is the perpetual
The calendar calculator module
contains a set of levers and cams that create the rules through which the
calendar module becomes a 'third order' perpetual calendar which keeps the
calendar in step with the Earth's time. Basically it accounts for the
quadrennial leap year, the one hundred year exception rule and the 400 year
exception rule. Making it good for 400 years. Very few clocks have come
equipped with such a calendar and when they do it is because it is a
component within a perpetual Easter computus indicating the moveable feast
of Easter, the Easter computus is the most complex complication in horology.
Only a handful of clocks have ever been made with this function. But unlike
these other calendars, ours also works in reverse. The reason for this
feature is that the calendar acts as a temporal reference for the machine's
celestial indicators when in demonstration mode in forward or reverse and it
easily allows the machine's operator to reset the demonstration back to the
present day after the demonstration is over.
Compare the finish of the cam module and dial work in
this photo to those of the module finished below.
The six photos above show the dismantling of the cam module.
These photos show the finished date index wheel, surprise pieces and
cam cage surround. Notice the tiny
beautifully shaped and blued indicator hand for the 20 year cam dial and
crenulated date index wheel.
The components in this photo show the finished date index wheel, surprise
pieces and cam cage surround in the center; contrast the pre-finished and
tarnished month cam, left, and right, the compound 20, 100 and 400 year
cams, have yet to be disassembled.
The month section of
the cam module is finished, excepting dial work.
The first photo shows the main frame for the 20, 100 and 400 year
cam work, next the 400 year Geneva cam indexer (on finger) with the Geneva
cam and cam frame in the background.
A small drive wheel,
left, upon which the 400 year Geneva cam is mounted.
The various setting
dials for the cam module from left, month, 20, 100 and 400 year dials. Above the
year readout digit wheels and dial mask. These parts are now finished in a
French silver matte finish.
The parts for the calendar calculator cam module are finished and ready for
These two photos show the build-up of the main assembly with the 20 and 100
year cam work and the 400 year cam work sub-assembly.
Components ready for final assembly, next photo the month cam work
placed upon date index wheel. Note the three 'surprise pieces' at the top
which account for the differing number of days of the months from 29, 30 and
31. The term surprise piece is the nomenclature used for parts within a
watch where those parts perform the same function for calendar, chime repeating work
and other horological complications. The
parts are designed to move in a calculated way to create a different output at the
Completed module from below.
Completed cam module showing the main components controlling the temporal
functions from bottom to top: the main module toothed drive wheel, next the the
crenulated daily index wheel, next the month cam, next the 20 year cam, next
the 100 year cam and on top the 400 year cam. In the background one can see
the three 'surprise piece' levers.
This video shows the reassembly of the calendar calculator module.
The calendar module installed within the rest of the machine. Notice the
beautiful bronze gearing within, contrasting with the other brass wheel
And now a treat for the hard core gear head. This video shows the
movement freewheeling and is achieved when pendulums, escapement pallets and
all astronomical components are removed, all of the four main trains, time,
celestial, quarter and hour trains are in freewheel. The time train is
running 24x normal speed, strike trains are at normal speed due to the fly
governors; this difference puts the strike trains in near constant activity
as they are being continually tripped by the speeding time train.