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Finish celestial train, finish strike train control lever work - May 2020

In this month's installment Buchanan completes the final finishing of the celestial and strike trains. The celestial train module is the most complex of the three main modules that sit upon the flat bed foundation frame. Many photos are in large format to give the viewer a good look at the quality of the parts and finish.


Notice the complex link shape for the remontoire chain which then requires an interesting articulated rim on the pulleys.


Left, a close up example of the precision machining to produce a complicated-shaped arbor. Right, the Robin remontoire fly governor. Note the decorative fly fan blades. This fly is purposefully located deep within the machine so that one does not notice it until it is tripped, furthermore its cycle is not consistent in that it releases on average of once per minute, but is actually composed of five slightly differing cycles a bit less and a bit more than one minute. A fly with a consistent cycle tend to get ignored, but with varying times this will tend to catch viewer's attention, and it being inside the complexity of the mechanism gives the illusion of a butterfly trapped within a cage.   

The photo above and below are parts of the Robin remontoire and overrun safety clutch. Part of the clutch was covered in April’s segment and is needed because both the time train and celestial trains share their power. At first it was the sharing of the time and celestial train weights but now it is the springs. As it turns out this is necessary with the springs too since the spring size needed for the time train would have had to have been very large, precluding it from being fitted into the area formerly occupied by the winding barrel, see photos near the end of this installment. So it is analogous to the former weight which also had to be very large, about 150 lbs. for the time train and only 30 lbs. for the celestial train, the same sharing arrangement is needed with the spring conversion.


The left photo shows the fly governor for the Robin remontoire. Right photo is a view of the right chain pulley and mechanism below as part of the safety clutch mechanism which was explained in April's installment.


Both Robin chain pulleys are shown in the left photo and the weights with their chains to the right. Pivots are jeweled and in keeping with the rest of the machine's design, are held to the weights by a delicate ivy shaped support.

The pad near the bottom of the frame serves as the actuator for the safety clutch in case of a jam within the celestial train. It is not as it would seem in a conventional Robin remontoire as the trip for the normal cycle of the remontoire, again this is covered in April's installment.


The celestial train module is the most complex of the three main modules that sit upon the flat bed foundation frame. Part of the reason for this is that in addition to driving the celestial functions, it also has the clock escape wheels, thermometer, quarter and hour strike detents, a drive wheel assembly leading to the quarter strike train and the rear pendulum support frame. Yet even barring these it would be as as or greater in complexity as the time train containing the dual Wagner remontoire.


This video shows the completed and final finished celestial train on a turntable to show the various components. This train is responsible for driving nearly all of the many celestial complications. It also contains the clock's escapement, thermometer, strike train detents and rear pendulum and beat plate mounts, so as a stand-alone module it is the most complex of the three main train modules mounted to the base flat bed frame containing the four spring drive barrels. If it were shown stripped of any components not connected to the celestial train's function, it would be second or third of the three modules in complexity.

--- Buchanan now turns to the finishing of the strikes trains begun last month ---


Various strike train parts after finishing.

Another view of strike train parts finished.


Left photo is a close up of the quarter strike snail made to look like a slice of a Nautilus shell, next heat-shaped cams used to articulate the rack gathering parts (which are made to look like pecking birds).

Now let's put it all back together!

The strike train control lever works: racks, gathering pawls, detents and snails from a three-quarter view. Notice the additional coloring of the red jewelling and blued screws that add to the silver background of the lever work which, in turn, is in front of the yellow brass of the machine.

Upper-front three-quarter view of the strike train lever works.


This video shows the demonstration of the quarter and hour strike trains after final finishing work. Note that the bells are not connected. The gathering pallets have been taken to an extreme here; instead of a single or double toothed pinion we employ two pair of bird analogs alternately pecking at the quarter and hour racks to count out the strike sequence and raise the racks back to their starting positions. Toward the end of the video one can see a pair of bird feathers alternatively moving on the right of the frame, these are the hammer actuators. The idea for having a pair of pawls to serve as a gathering for a toothed rack was inspired by the date rack in the Easter Calculator located in the astronomical clock of the Strasbourg Cathedral completed by Jean-Baptiste Schwilgué in 1843.


The curved section allows for easy installation and removal of the steel band holding the pull-repeat weight. The same weights and steel strips are used in the dual remontoire located in the time train, next photo. Notice the small screws under each weight allowing one to remove the bottom and add or reduce weight within the cylinder using lead shot.

These photos show Buchanan’s replacement of a flat steel strip for the watch fusee chain we had before. I had sent him that fusee chain about ten years ago for this purpose and the idea was based upon the original dual remontoire as seen on the Gillett and Bland tower clock installed in the Royal Courts of Justice in London. Buchanan had sent photos of the clock to me in 2005 and I had looked up the design in the Patent Abridgements, Horology, Vol. 1, 1855-1900, A.D. 1877, page 1, patent #29, January 2, Gillett, W, and Bland, C. (it appears that the British numbered their patents sequentially by year, starting from the number one each subsequent year). The fusee chain however was too thin looking and worse, did not want to stay straight like a link chain would (fusee chain was never designed for this purpose). See a link to a video of the link chain used in the Gillett clock.

--- Buchanan now turns to finishing of the pendulum beat plate, spring adjustment vernier controls ---


This photo shows most the various parts in the beat plate and vernier controls..


The first photo is a close up of the small parts in the upper right hand corner of the photo above. Next photo shows the upper vernier spring adjuster.


Another shot of the upper vernier and the second photo a rear view of the lower vernier.

The photo above is the assembled lower vernier, shown upside down. Note the classic stepped foot. One has to say it does have an insect-like appearance.


Timing is affected by the verniers located on the rear of the clock at the upper and lower points where the pendulum balance springs are located and can affect the tension of those springs not unlike what John Harrison did on H1 through H3. But this is where the similarity ends. Harrison used temperature compensating gridirons on H1 and H2 and then a bimetallic strip on H3 to control the tensioning of the plain steel springs in line with temperature change. We have substituted springs made from Elinvar NiSpan-C; similar to the material used in better watch hairsprings. Elinvar maintains constant elasticity vs. temperature. This is as important to springs as Invar material is in keeping a pendulum rod a constant length vs. temperature. So once the verniers are set, there should be little fiddling with them to maintain reasonable time.


These two photos clearly show the spring conversion; they look better than the prior winding barrels. One can also see the difference the spring size from the smaller springs for the strike train on the left and the one for the time train, right.

Is this complicated enough?

Total parts count to date: 4980

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