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Continue tellurion assembly - September 2015 

This month we continue the fabrication of the tellurion complication.


The wheels now begin to be cut out. Buchanan writes: “The last two wheels and pinions relating to the sun are finished. I have measured the depthing for them and one set of pivots is drilled in the plates. The reworking to double tooth counts took longer than expected. Tomorrow I will have the other arbor fitted and hope to make a start on cutting the last pinions on the earth side of the tellurium. I have the two arbors which carry wheels 5, 4, 23 and 43 to fit next, then I can mount all the idler wheels (2, 3, 21 and 22).” These numbers refer to the checkerboard pattern locator for each wheel component in the grid box described in the August segment. The doubling of the tooth counts were made in connection with the enlargement of the idler wheels for aesthetic reasons.


Here additional wheels are added. The second photo shows the wheels that will be added on top of the second plate, making this a triple frame construction.

The staking tool is used to set the center arbor.

The completed gear set illustrated here from the staking photos above with the wheel train to this point.


The first photo shows the small scale we are getting into for some of the pinions on the tellurian. The smaller pinion is six leaves, 0.15 module and 45 thousands, or 1.14 mm, the larger is pinion is 61 thousands of an inch or 1.54 mm in diameter. The wheel is 0.75 inch in diameter (1.91 cm) and this wheel has 128 teeth. Buchanan writes: “When cutting the pinions I cannot use the normal gauges on the machines for measurement as the adjustments are too small. All I can do is to cut sample pinions in brass and make the smallest adjustment possible and then cut another sample. I must have cut ten trial pinions today to get two beauties. I have one more pinion and 3 wheels to cut.”


The tiny pinion shown above is now mounted to the wheel, red arrow. Next a set of wheels is shown in relation to a centimeter calliper open just over 2.0 cm.


 This photo has a number of the wheels produced so far. Buchanan writes: “Wheels 4, 5 and 6, complete. These are most but not all the complete wheels. I have two more arbors to complete before I can plant this whole assembly. Wheels 11 and 12 and wheels 10,  20 with pinion 9.Then it will be idler wheels 2 and 3, then idler wheels 21 and 22, then the last few wheels up at the moon and earth, 17 and 19 and 39, 40 and 41.”

The staking tool is used to attach the tiny pinion to the mating gear. Next a pinion gear gear is attached to its wheel. Both parts seen in the last photo. The small gear measures 0.5 cm, the larger wheel just under 2 cm.


The first photo shows a set of wheels that will undergo depthing. These are small enough to require a watch wheel depthing tool. 


 Note again the use of a microscope to aid in this process.

Below Buchanan begins the process of planting the numerous wheels in this section. He writes: “This morning I have finally worked the full sequence of pitching the pivot holes and this is in progress, I have taken photos of the three stages to arrive at the pitching. The first photo (ubove) is the various factors that affect each pivot. This takes into account interaction between other arbors, as well as clearances between wheels and collets or bearing housings. That is after I already have the actual depthing dimension. I then drew it out 40 times oversize to check my calculations physically (not shown). The second photo (below) is the final dimensions needed on the jig borer. 620 (the second photo below) is setting up to drill the first hole.”


Shown here is the the set up to drill the first hole in the lower plate. Next the same set of four wheels shown earlier in the watch depthing tool are planted.


The first photo shows the 30 wheels made to date. There will be 43 in the tellurion assembly when finished. Buchanan writes: “I have all the pivots drilled. Everything fits with no disasters, “Phew”. There are 5 adjustments to make to the various wheels. These are height of wheel on the arbor type adjustments. Then I will start on the 4 idler wheels which will mean that we will see the basic mechanism operational.” Next the the four idler wheels are made. There are five wheels shown but one of those will be made up of a sandwich of two identical wheels.


The four idler wheels are now cut along with their screwed on collects, the last one to the right is the double-layered wheel. Even these small collet parts are beautifully cut. I have never seen a tellurian or orrery for that matter where all of the wheels have separately screwed-on collets rather than the wheels being staked upon their respective arbors. Let alone the entire set of pivot holes being jewelled.


A side view of the wheel set clearly shows the dual layered idler wheel, yellow arrow. This is used to transfer power from the lower wheel located at the base of the central Sun arbor up to the next wheel located a bit further away from the plate.

Nearly all of the wheels have been completed and arranged on the tellurion schematic.

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