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Unknown, Paris, France, 1786. Single train 14 day duration, tic-tac, one-half second pendulum. Movement with front gilt plate surrounded by three bronze figures of Atlas holding a glass celestial sphere; within the sphere a clockwork-driven orrery with plants to Saturn including working Earth-Moon system.

                                                                                      Restoration photos of the clock. Various repairs and corrections.

 

The orrery as received was missing two pinions which are needed to drive Jupiter and Saturn planet arms. I had these made for the project, first photo. As illustrated in the second photo these would be mated to what I call the 'drive cone'. All the wheels and pinions are joined. The lowest and largest wheel receives input, the next three wheels and two pinions are for Mercury, Venus, Mars Jupiter and Saturn. The Earth/Moon armature are driven separately.

 

The pinions installed, first photo. I do not know why the supplier used a brass pinion, but everything moves so lowly at this point of the mechanism that it really doesn't matter. Notice how the drive cone meshes with wheels of an opposite size, in other words the smallest pinion drives the largest wheel and so forth down the five wheels of the cone. Of course this is the way the planets orbital periods are correctly depicted since the periods get longer as one moves away from the sun. This pairing is made more apparent in the second photo, taken after the orrery was polished.. Fortunately the concentric tubes were undamaged so they fit perfectly.

 

One of the stars used to represent the planet of Mars was missing. A computer group I belong to gave some interesting sources to look for a replacement. To be honest I was skeptical that I'd find a close match, but luckily there was a perfect match in as far as the star profile, however it was only a half thickness, whereas the original was mirrored on both sides. This was a simple procedure to glue together and use the same glue to attach it to the armature. Soldering would be the more traditional way, but I thought that no matter how careful one could be there would be a tiny silver seam around the edge.

 

The result was a very good match that could only be improved on if I were to locate, or cast a star. Casting was not possible as this is a skill I do not have, nor want to practice for one star! Casting would also have required the removal of one of the other original from their armature and they looked to be soldered in, again not wanting to risk damage by unsoldering and then re-soldering. The armatures were originally gilt and while somewhat worn, the gilding was evident.

 

About half of the screws were very corroded, in fact the only screws not corroded were those that were under the orrery table and the orrery support plate. I like to keep things as original as possible, however if a screw was originally blued and is corroded beyond what looks reasonable I will re-blue it. Bluing is a simple, straight forward process for small parts. Notice that I did not use an abrasive to make the surface perfectly smooth. I did not want the screw to look new, so I leave the pitting in place, but make sure the pits are clear of any residue.

 

At the right color the screw is quenched. Depending on the look I want I may leave it as is or rub it around in a lightly oiled rag. 

 

Once a part is polished I then use latex or cotton gloves. I'm interested in trying the finger coverings as this avoids the sweat that occurs with latex after a while, and cotton gloves are fine for larger parts and easier to remove, but small, delicate parts tend to get caught in the weave where an accident could happen.

Here the movement is finished. The arrow points to the arbor that has a small hole through which one end of the silk suspension thread is tied. The section which extends past the plate is square to accept a tiny key. By rotating the arbor one can change the rate of the pendulum.

Here is where an interesting story begins. As found the arbor was located here. I was a bit concerned that it freely rotated so how would it hold its position with the weight of the pendulum pulling on the thread wound around the arbor? I set that concern aside for the moment.

 

In the first photo we have a side view to show where the rating arbor is located, black arrow. The next photo was kindly provided to me by the curator of the clock collection belonging to the Worshipful Company of Clockmakers. They have in their collection and I has seen in person, a clock nearly identical to this in 2011. That collection is now housed in the British Science Museum. One can see that the clock frames are virtually identical as are the planting of the wheels and orrery demonstration gear drive. Note the white arrow showing the rating arbor in the same place. The is likely the correct spot for this style of celestial orrery. There are many types and these will be compared and contrasted on the next page.

 

The first photo shows a rear, left three-quarter elevation of the movement. Again the black arrow shows the end of the adjustment arbor. Look carefully where the arbor is positioned with regard to the gilt dial surround. It is hopelessly blocked by the surround as is obvious in the second photo.

Remember the anomalous holes pointed out on the prior page and how only one set were mirrored on both the front and rear movement plates? The second photo shows the hole on the front plate and how it neatly fits in the open space between the two arched leafy branches. Someone had also punched curious triangular indentations around the hole.

 

I then disassembled the clock and place the adjustment arbor in the new location, it fit perfectly and the punched hole in the front provided just enough friction to keep it from freely rotating. So in order to keep the adjustment function that arbor was moved. Why in the name of all that is proper, didn't the person punch the hole in the rear plate instead of leaving a set of ugly punch marks on the front? I now know what the original arrangement was. So the clock was made with the adjustment arbor hole just above the dial, but at some time before delivery to the customer, the dial surround was added and the adjustment arbor located higher up to accommodate this option. The two cheese-head screws at the top of each plate were severely corroded and re-blued. Fortunately the gilding on the dial surround was in very good condition.

Here is one area where I decided to make a change. To cover those ugly punch marks I took one of the stars I had left over and attached it to the square end of the adjustment arbor, thus hiding the punch marks and giving continuity to this fix with the stars in the orrery. The attachment is fully reversible.

 

These photos show the structure of the dial and gilt surround, In the first photo the black arrows show where the dial feet are. The two arms are attached to a small plate that has a hole which fits over the dial foot. Those arms reach upward to attachments under the orrery support plate.

 

The first photo shows another celestial sphere clock with the same gilt dial surround. In that example the simpler and more straight forward solution was taken by simply drilling a hole in the decorative surround for key to turn the adjustment arbor. One can also see that the wheel planting with the plates was slightly different as the main barrel winding arbor is lower than the one in this example. This is a good illustration of how by the end of the 18th century clock making was a fully integrated industry with specialized companies to make the movement, orrery makers, casters making the gilt surround and statuary, and dial makers for variety of made-to-order clocks by different makers to the end customer.

 

The view of the top of the orrery table after finishing, first photo. I purposefully did not polish out the shadows of the stopped wheels that were etched into the surface from contaminants falling from above. The prior page has the before look. For oxidation to have made such a picture the wheels must have been frozen for a very long time, perhaps over a hundred years or more. All parts are first put into an ultrasonic cleaner using a water-based degreaser to remove dirt and old lubricants then I use Simichrome as the polishing medium and a soft terry cloth for larger, less fragile parts, polishing by hand. For smaller parts and areas, as illustrated in the second photo, the thin rims and spokes of the wheels are initially treated with a cotton wheel charged with the same polishing compound. I use the slowest speed available. Afterward the entire part is carefully finished off by hand to achieve a mirror polish. This two-step process is used in this project because the oxidation is quite extensive. Otherwise everything could have been done by hand. Afterward any polish residue is removed in the ultrasonic tank.

   

Polished orrery parts now ready for reassembly. I took care not to polish the concentric tube work, except the outside of the outer tube. This was to lessen any material removal and the fact that these areas cannot be seen after reassembly, and results in the tubes being as closely aligned within each other as possible. A dry Teflon lubricant was used for the concentric tubing, thus avoiding any oil creep as well as contamination from dust or pollution, particularly because of their vertical orientation.

 

Two views of the orrery wheel work.

 

Another photos set. The Earth/Moon armature is seen ready for mounting in the second photo. 

 

A before and after shot of the orrery.

 

The first photo shows how the orrery armatures that represent the planets of Mars Jupiter and Saturn can be folded to allow the neck opening of the glass celestial globe to be lowered past the orrery. Next photo shows the re-installment of the three Atlas statuary.

 

The clock and orrery are installed within the statuary, orrery is still folded, in the next photo the arms are deployed.

 

The clock as received was missing its pendulum. Given the photos of the clock from the Worshipful Company of Clockmakers, the original was probably a simple tapered cylinder that had a smaller diameter at the top and a larger diameter at the base. I had looked for one like this or maybe even a pear-shaped type that was also popular on verge bracket clocks at the time. A reproduction silk one-half second thread pendulum was available on the web. The correct length is far shorter, so this had to be fabricated. The rectangular metal shape that was designed to meet the pendulum crutch was much longer and wider than that which was permitted by the original rectangular opening in the extant crutch. That part was fabricated to better fit what was called for in the original design.

 

However, there was a problem. The clock ran well with the temporary pendulum, the total weight being .45 oz. The replacement pendulum was over 1.2 oz and was too heavy for the clock to drive. One option would be to make the simple, small tapered cylinder, or alter what I had on hand to reduce the weight. Again here I have made a change as I did with the star to hide the ugly punch marks around the pendulum adjustment arbor and this too is completely reversible. Much of the surrounding material around the face was removed.

 

The final weight of the reworked pendulum came in at .47 oz compared with the temporary pendulum at .45 oz. and works well.

 

The revised pendulum in place, and in the second photo the silk thread wrapped around the adjustment arbor in its place, black arrow. The yellow arrow shows the empty hole where that arbor was originally placed. One can see where the suspension mount has a 'V' cut into it to accommodate where the arbor would exit the hole. This is obviously where the original designed called for it to be.

Collecting clocks can be fun!

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