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Assembly of the time train - January 2020

This month the components within the time train frames are polished and reassembled as well as other small housekeeping items that have been left over from prior construction. The time train does not, however, contain the escapement, it is driven from this train but is located within the celestial train so it can be located in the center of the clock. The bulk of what is in this train is the complex dual remontoire, and the sidereal time complication. Additionally there are other components and equation of time complications, these will be added next month.

A real treat is the video of the reassembly process. Anyone who has tried to reassemble a three-train quarter chiming movement usually finds getting all the pieces and arbors into their proper place to secure the movement plates to be a challenge. This takes the job to an entirely new level.

This also touches upon the first major design change that was made in the project in March of 2009. At that time it became apparent that the original basic frame design based upon a plate-and-spacer configuration like that of the quarter chiming clock movement would not be desirable. While there would have been many smaller sub-frames within the main outer plates, there was no way to make this design practical for the scores of disassembly and reassembly cycles needed throughout the construction process. The main outer plates would also have been large, heavy and unwieldy to try to fit many dozens of wheels simultaneously. Our solution was to make three modules based on a hybrid pillar and frame and to mount those to a common base frame. In this way the reassembly can take place in smaller segments making the process as well as any future servicing an easier task, or at least as easy as can be expected for this machine. See two photos below.


The time train module before disassembly for polishing. As was described above, there are no conventional frames, but a series of pillars. This was the first type of frame design used in horology, and was seen in chamber and tower clocks from the 11th century; known as 'bird cage' frames and recognizable for their open architecture and is shared with the time train pictured.


Another view of the time train module before disassembly for polishing.

All of the time train parts are laid on the table. Notice how dull and dark the parts are. These were first completed in July 2008.


These photos drive home the difference between the parts before and after polishing. Recent photos and videos of the machine before the current polishing process did not fully reveal the extent of the tarnish, while it was obvious that the parts were not fresh, the real impact of the tarnish comes through when the machine is disassembled. One can see just how darkly tarnished the parts have become over the years. Hopefully with the frame pieces lacquered and the clock in a proper case, protected from handling and in a clean environment this will not reoccur for a very long time.


Here are two of the ongoing housekeeping items. The first photo shows a beautifully turned collet and what a similar collet looks like before. Another example is the installation of a biasing spring, arrow, to better secure the sector gear’s following arm to the perimeter of the equation of time cam, second photo.

Remontoire components


The first photo shows the remontoire fly fan frames, the next photo shows a pair of flies that compose one of two such assemblies (a total of four flies).

This close up photo shows the design of within each blade is actually a "B" for the Buchanan firm.


These three photos show more of the remontoire components.


The second photo shows the same part close up as that seen in the lower right hand corner in the photo just above. It serves as part of the splitting differential within the remontoire is made to look like the main winding wheels located in the base of the clock, first photo from September 2007. It performs the same function; having planet wheels located in the three spaces just as in the winding wheels. The main wheels are about five inches in diameter (12.5 cm) while this part is about two inches (5 cm). This attention to design consistency is a part of what sets the Buchanan firm apart.

This photo shows the dual remontoire trip release cams. Each cam makes one revolution every two minutes, the four arms result in the remontoire being released every thirty seconds; since the cams run in a fashion where the arms are staggered between each other the result is a release of one of the pair of remontoire fly fans every fifteen seconds. There is a small spring between the cam and its drive wheel to cushion the sudden stop when the cam locks, preventing the large remontoire cages from jarring.


These photos show a partial build up of the remontoire rocking cages.


These three photos show the remontoire splitting differential which allows the dual remontoire to operate independently from a single drive input. This is the heart of the dual Wagner remontoire and is performed by the part described as a sister to the main winding wheels; and is the cage in the center holding three planet wheels.

The frame parts are now polished and lacquered. Look carefully at the beautifully milled square areas just above the open holes on the two lower frame pieces. These will serve as a classical base to the Tuscan style columns that support the remontoire fly assemblies, they also support the pair of remontoire assemblies.

Sidereal time complication

The main components of the sidereal drive complication. The two rings on the lower right are the minute and hour dial bezel mounts that rotate counterclockwise. Look at the delicate taper of the spokes in this and the following photos.


The Buchanan logo is stamped on the outer dial bezel mount, first photo. Next a close up of the eight screws that secure a large delicate wheel to its collet.


Just a twitch of the hand would be enough to deform these precision parts. Imagine the care needed when they must go through the polishing process.

This photo illustrates Buchanan's ability to combine precision fabrication and artistic ability. The actual size of these parts  is a little over 1 inch (4 cm) in diameter. This is part of a very decorative caged roller bearing.


In the first photo components from the photos above are installed. The second photo shows the layers of components within this part.

The sidereal time complication completed with the decorative caged roller bearing at the center.


This video shows the finished sidereal dial assembly. The two rings will hold the minute and hour sidereal time dials and rotate counterclockwise within the mean time dial, which also has the equation of time indication. The center section is an elaborate roller cage bearing, but uses delicate wheels in place of balls in the manner of George Harrison's design for the world's first caged roller bearing in his marine clock H3 completed in 1758; an invention upon which all modern machinery rests. Have you ever seen a roller bearing like this before?

Parts count at this time is 1699.

Another example of Buchanan's work. This photo is approximately 5 times magnification. Even at this magnitude the part looks perfect in terms of polish of the pinion and wheel surfaces, the sharpness of the spokes and wheel edges, the color of the blued screws.

This photo is the time train clutch mechanism. Look at the beauty and balance between the blued spring steel used as the gripping force against the same spoke configuration of the wheel held by turned pillars and all this is moderated by the pair of precision knurled adjustors.

Disassembly video


This video shows the reassembly of the time train. Notice in the first two short clips how long the splitting differential coasts until it come to a stop. This is a demonstration of the extremely low coefficient of friction the ceramic ball bearings have compared to conventional steel bearings.

Reassembled time train


This video shows the completed and final finished time train on a turntable to show the various components. As a stand-alone module it is second in complexity to the celestial train. However, the entire escapement, pendulum and second remontoire governor assemblies are not present. If each train could be shown with its full complement of components outside of the machine (which is not possible) it would be a close comparison to the strike trains for complexity. In all there are four trains contained within three modules that sit upon the flat bed base containing four spring barrels.

In these photos the frames nearly disappear amongst the forest of wheels - exactly the effect I was looking for.

Wheel heaven...

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