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
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
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
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.
“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.
photo has a number of the wheels produced so far.
“Wheels 4, 5 and 6, complete. These are most but not all the complete
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
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.
again the use of a microscope to aid in this process.
begins the process of planting the numerous wheels in this section. He
“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
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
The second photo
is the final dimensions needed on the jig borer. 620
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
first photo shows the 30 wheels made to date. There will be
43 in the
“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.
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
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
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