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Continue Sun / Moon rise set, finish sun hand, glass dial frame, shutter setting dial - September 2017
The temporary blue plastic sector pieces are now installed in the horizon shutter frames and the center dial is complete. The night indicator is actually polished, blued steel as seen in the second photo, but looks black when viewed straight on. The upper day sector is silvered brass.
The complex dial is coming together, one can see the paper mockup dial tag designs are still yet to be refined.
Here is where Mr. Sun
gets his eyes. Buchanan needed a way to secure the sun emblem onto the drive
pad. The easier way to do this would have been to secure the sun via blind
holes through the rear of the sun and through the pad. But here the artistry
and imagination of Buchanan shows again. He will secure the sun emblem the
same way except instead of blind holes, the holes are positioned where the
eyes are in the face and drilled straight through the piece via the eyes
with the ends of the screws being domed, polished and blued giving the sun face a
set of blue eyes. In the first photo the cast eyes are drilled out and next
the holes threaded, ouch!
The tiny screws are now
fabricated starting with the blank rod stock being run through a threading
die. Next a magnified view of the threaded rod.
In the first photo the screw head is slotted with a micro-fine slitting blade. The screw is held in a lathe collet and the blade is run past the two upright rods on either side and since they are exactly 180 ° opposite each other the cut always perfectly bisects the screw head. In photo two the end of the screw, which will be the eye, is polished and then blued.
The first photo shows the diminutive size of these screws. Next the finished product, the sun now has a brand new set of blue eyes! Buchanan writes:
I
have mounted the sun on its support by the eyes. So we have a sun with Blue
eyes! The screws are 20 thou, thread 203, threads per inch (0.5mm by 0.125
pitch) I think they are the smallest on the clock so far. I may have used
smaller on the calendar but I don’t recall. I can’t blame him for
not remembering since the calendar was finished in July of 2015 over two
years ago. It seems like only last year…
The blue eyes are a bit
more evident in this photo.
The glass dial frames
have been finished off into their rounded profile.
The frame surrounding
the mockup moon shows the perfect fit and finish of the surrounding
material.
The glass dial rims
shine in these photos.
But oops! Mr. Sun’s sun ray at 12 o’clock as well as his nose hits the horizon shutter’s edge, ouch! The sun ray will have to be paired back, but the nose can be saved with the recess into the shutter frame. The Devil is in the details.
As the number of dial
tags began to fill in I became concerned with the look of clutter. I wrote:
I am wondering about the plaques attached to the bezel, the ‘Moonrise/ set
times’ and ‘Right Ascension’. These break into the bezel and cause an
imbalance with the outer bezel of the calendar module. I’m wondering if,
depending on the final design for the bezels, instead of a plaque these
could be engraved directly onto the bezel on a flat spot? This would
completely incorporate the plaques and keep the symmetry. Perhaps the right
ascension plaque could also be handled in this same manner; does it have to
be below the Moonrise Times plaque? Also you may be able to get away with
the plaques simply saying Moonrise and Moonset, wouldn’t the numbers on the
glass dial be obvious that these are times? This would be especially true if
a pointer hand would extend from each to the hours on the glass dial, like
what the right ascension plaque is illustrated doing. Of course there is the
problem of clearance for the moon sphere. Looking at this more, the ‘hours
until’ and ‘hours since’ make more sense, or maybe ‘hours before’ and ‘hours
after’? There could be a small pointer at the end of each, as I assume one
is now reading the hours until and since off the edge of each plaque, the
pointer may make this a bit more obvious as to where to look. Buchanan replies: I was thinking exactly along the lines you are suggesting. The main Moonrise and Moonset will be part of the bezel so that there are no protuberances. This is also why I was thinking of using print and nor script. The overall height of the engraving is reduced so that we can recess it into the bezel. The Right Ascension will be the same size and plane as the Hours Before and Hours After. I like these better than ‘since’ and’ until.’ We have a clearance issue with the moon. I could lift the glass to the level of the top of the moon but the moon will then appear sunk into the glass disc and we lose some of the 3 dimensional look. You will see that I have a black triangle on the edge of the moving plaques to show the reading edge.
This video shows a manual demonstration of the various dial segments in the sun/moon rise-set module; the sun, moon, horizon shutters, length of day/night hours dial.
We need a setting dial
to adjust the shutter cams. A paper mockup is shown here. Buchanan
suggests that if we show where the solstices and equinoxes are on the dial
we will have an additional complication.
Buchanan writes: First dial is a dud. There was a typing error in the machine code for a depth of 2.5mm deep instead of 0.25mm deep. Can you spot the mistake? I reply: Nope, April looks great!
The engraving for the shutter cam setting
dial has a very fine detail. Buchanan writes:
The setting dial came out good. The engraving is a little deep at the moment
to allow for the final polishing. When we sand paper it down more, each line
becomes thinner, because the cutter is tapered.
The
depth of engraving is another demonstration of Buchanan’s forward thinking
and attention to every detail.
The
horizon shutter adjustment dial, located at the rear end, is test mounted to
the output drive module.
The first photo is of the knurling tool. Next the tool is about to be
applied to the rim blank.
Here the knurl is complete. Next the knurl is parted from the blank
resulting in a delicate ring.
That ring is then applied to the engraved wheel and that wheel is next
shown attached to the drive wheel connected to the horizon shutter sector
gears.
To aid in adjusting the cam work, this wheel needed a knurled edge. This
allows the operator to set the shutters to the correct date at the
designated latitude of Chicago, Illinois. What really impressed me was the
fact that Buchanan did not simply knurl the edge of the wheel but made a
separate knurled ring that was just a bit thicker than the wheel to attach
to the dial ring perimeter resulting in a raised rim; giving the overall
effect of a coin. I have to say this really impressed me and when I asked
why he did this he answered that the wheel itself was to be silvered but the
knurled edge must remain a brass color and that it would be too difficult to
do this with the knurl on the wheel’s edge. He will silver the wheel and
then attach the knurl ring. How this is done without damaging the silvering
I do not know. I think most other makers would have found a shortcut around
this, but Buchanan’s talents are so refined that the manufacture of a
separate ring was not considered a problem.
Here the indicator hand is shown. The angled profile was needed to allow
the end of the hand to be where the operator could see it against the
adjustment dial. In the next photo the hand is attached to a nearby pillar.
The indicator hand is
just visible in front of the shutter adjustment wheel. Just beyond, in
between the frames the pair of horizon shutter sector gears is visible.
The first photo shows a pillar modified to hold the bias springs complete with custom seats and locating sides walls. These springs keep the cam followers seated on the cam edge. Again I would point out that most other makers would take the easier way of simply cutting a flat into an otherwise conventional round pillar instead of making a raised seat. The fact that the seat is raised above the diameter of the rest of the pillar requites special hand work on the lathe as seen in the video below.
In these photos the
frame is drilled to receive a stop pin that will intersect the pillar to
prevent any rotation of that pillar from the bias springs. 
 The hole and taper pin are shown in the first photo. Next a spring rod is fitted one of the cam followers. This will later be trimmed and will serve as a banking pin contacting one of the bias springs.
In these photos, the rod is trimmed into a banking pin and is used to engage the ends bias springs mounted to the pillar.
An overall view of where the sun / moon rise-set module is at this time. The moon orbital variable differentials which would be mounted behind this assembly are complete but are not installed in this photo.
The Astro-skeleton to date, with a the central orrery mockup installed, The rest of the machine as shown is fully operational. |
