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Continue strike train, begin finishing of celestial train  - April 2020

This month Buchanan continues the strike train and begins the celestial train, the last and most complex train responsible for driving the myriad complications. Many photos are in large format to give the viewer a good look at the quality of the parts and finish.


The first photo shows parts making up the strike repeat trip mechanism prior to dismantling.

The parts from the first photo now dismantled and finished.


This photo shows the connection between the parts illustrated in the two photos above it.


The first photo is the trip lever. Next the finished components of the trip-repeat mechansim.

Most of the hammer actuator parts. The two bird analogs on the right will have jewels for their beaks and this part is what will engage a rotating carrousel driven by the strike train work.


First photo is one of a pair of the completed quarter strike bird actuators, second photo.

Completed quarter strike hammer actuator assembly. The stainless steel arbor and actuators attain a high corrosion-proof polish.

Finished parts for the quarter strike hammers.


The first photo shows various parts held aloft for lacquering. Next the completed pair of quarter strike hammer heads and arms.

The completed quarter and hour strike hammer assembly.


The quarter and hour strike train components.


The first photo shows the Buchanan signature that appears next to each of the three hammer percussion adjusters. The next photo shows a close up of the re-installed strike trip mechanism.

Another view of the upper portion of the strike trains. One might say the two drop-down frames between the two main frames in the strike train, could technically make this a quadruple frame, but the two center drop down structures do no encompass the full frame size, they do, however, have the majority of the total strike train parts between them and the outer frames.

Left, three-quarter elevation of the completed quarter and hour strike trains, less fly control governors mounted to lower base frame.

Right, three-quarter elevation of the quarter and hour strike trains, strike less fly control governors mounted to lower base frame.


These are not the strike fly governors, but one of a pair of the compound fly governors that mediate the functioning of the time train remontoire. This one is installed on the top of the strike train, the other is on the top of the time train. It is an example of some of the components of the time and strike trains being spread out over the entire mechanism to give visual symmetry and interest. In conventional construction each train would contain all of the functions of that train.

The first photo captures the classical column bases and fanciful finials of the fly cage. The second photo shows the detail of the upper columns.


This video shows the completed and final finished strike trains on a turntable to show the various components. This is only the quarter and hour drive trains with the bell hammers; less any of the complex strike control mechanisms - the levers, racks, cams, detents and fly governors. Even though this module contains two trains, it is the least complex, on a stand-alone basis of the other two main train modules, the time and celestial trains. To be fair many of its components are shared with the celestial train and if one were to be able to attach all the control and synchronization transfer mechanisms to the strike trains module while outside of the machine (which is not possible), the answer would be different. In all there are four trains contained within three modules that sit upon the flat bed base containing four spring barrels.

--- Buchanan now begins the celestial train ---


Buchanan begins the finishing process on one of the celestial train's main frames. In keeping with our naturalistic ivy, tree and animal theme this "tree" is not simply a flat piece of brass cut into the outline of a tree, but each branch grows thinner towards the top just as would be expected in a live tree. The three circles show how the limbs were made in three thicknesses as one moves toward the top.

The celestial train is by far the most complex of the four trains. The first indication of this is illustrated by the main frames shown above. At the end of each branch is a red cover over the ceramic ball bearing pivot point yielding the bright red fruit of the tree. There are three train modules but the quarter and hour strike trains are combined into one module and yet is the least complex compared to the time and celestial trains. This train is composed of three distinct frames, a full triple frame, two of which are shown here.

Part of what makes this train complex is the overrun safety clutch described below. This is the result of the fact that the time and celestial trains share the power of their two springs. Originally the clock was designed to be weight driven. The time train contains a lot of what I call "mobiles", parts that have a frequent and large-scale movement and so consume a great deal of power, in particular the  dual escapements, two remontoire and their fly governors. The celestial train drives many more wheels in the form of the celestial complications, tellurian, orrery, sun/moon rise-set, planisphere but all of these move very slowly in comparison to those in the time train and so require far less power. Having an individual weight for each of these two trains would result in a huge weight for the time train, over 150 lbs (68 kg) and a relatively light weight for the celestial train of less than a fifth that of the time train. So the decision was made to share the weight between the trains allowing for a more even distribution between the two trains.

However, should there be a malfunction, a jam somewhere, in the celestial train; given the two trains were sharing the weight load, it would also take down the time train, stopping the clock. The remontoire overrun safety clutch was developed to solve this problem by allowing the celestial train to be bypassed, but still allow the time train to access the celestial train weight. Relatively late in the project the decision was made to convert the clock from weight to spring drive and the reasoning is explained in the July 2019 installment, but the two trains still share their duties so the mechanism is still necessary. It is complex, yet beautiful.


These are other parts of the Robin remontoire. There many ways that the indexing wheel could have been made and this exemplifies how every part is considered to create a visual impression. What cannot be seen are slots behind the wheel which are spaced unevenly. This translates into the remontoire being released at six different intervals; some a bit less than once per minute some more but on average the remontoire will cycle once per minute. This translates into the remontoire fly governor being activated at uneven intervals adding to the interest to the viewer. The brain is wired to recognize and eventually ignore a repeating pattern. In this way we keep the interest by making the fly release at irregular interval. It is also located within the mechanism so when activated it looks like a butterfly deep within the forest filled with wheels.

The next part in the second photo is a pawl that prevents the index wheel from a backward motion.


The index wheel and pawl installed, next a view of a large of a pinion. Note the detail, Buchanan dishes the larger pinions which reflects light in a more interesting way than a simple flat surface, also look at the decoratively turned brass collet surrounding the arbor. The collect could have been dispensed with leaving the more conventional design of an arbor and pinion.

Additional parts of the remontoire before finishing. 


Additional parts of the Robin remontoire. The first photo is what is called a "hayfork" lever for its resemblance to that farm tool. The second photo shows an ivy curly-cue holding a leather friction pad, which contacts a smooth rim wheel attached to the safety overrun clutch mechanism, see below.


This is a part of the safety overrun clutch for the Robin remontoire, it looks like a chronometer balance wheel. Every screw, every spring down to this minute level is highly finished and blued, it is just about 1”, (2.5cm) in diameter.



Another component of the overrun clutch.


The first photo is the remontoire detent attached to one of a pair of pulleys located at the top of the Robin remontoire. The second pulley is in the next photo, it's complex articulated rim matches a chain made with ivy-shaped links. The wheel next to it is the same as the one directly above. 


The completed remontoire overrun safety clutch. The smooth rim wheel is what the leather pad illustrated a few photos prior to this one operates upon. each turned column is less than 1/2" (0.75cm). Even at this small scale nothing is left to anything but perfection.


The complex pulley rim pattern could have been made with solid rim retaining the pattern, instead it too is skeletonized between the pulley rims; another detail setting this firm's work apart from all others. This work harkens back to the index wheel found in the calendar's third-order perpetual module that was made in February 2015. It too could have been made in a much simpler way and still perform its function, but like the pulley illustrated above, was turned from a mechanical object to a work of kinetic art.



The overrun safety clutch trigger connected to the long lever that activates the overrun clutch. In the second photo the trigger is mounted to the inside of a main frame.


This is the trigger-pad which is the lower limit rest for the over run clutch. What happens is this. If the celestial drive jams, the larger weight  is lifted until it reaches the "hay fork" lever with the two blue pad springs and the overrun clutch is activated. The clock will run on unaffected by the jam. If the problem is removed  the remontoire will trip and drive the celestial train but not rewind until the weight reaches the trigger pad and then  the overrun clutch is reset and the remontoire operates as normal again.  Normal operation of the Robin remontoire is controlled by the long feed rod from the rear time train frame and feeds the skeletonized curved tooth indexing wheel with the inconsistently spaced release slots.

Parts count to date: 4164

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