Strike and repeat control assemblies, racks - January
Last month B had drawn his idea of how some of the basic strike lever components might
look like. However there was no provision for the complex repeat mechanism that must still
be incorporated and the silencing feature. Therefor, before any further fabrication can
begin, the entire strike mechanism must be incorporated. Shown above are several concepts
with the overall general schematic in the first photo. The next two show subset drawings.
The third photo shows the beginnings of an additional pair of fly fan assemblies that will
be used to gently drop the two racks onto the snail cams. This is necessary since the
snails will be delicately skeletonized out and the racks, especially the hour rack, are
quite large and damage could result from the rack tail hitting the thin snail rim.
Besides, what a great excuse for another piece of fancy equipment to mesmerize the viewer!
Now fabrication begins. The first parts are the cams which will serve to drive the
seesaw mechanism that will raise the racks during the striking sequence.
The first two photos show the rough out of the hour rack as well as the two circular
blanks that will later become the hour and quarter snail cams. The third photo shows the
first trial set up of the seesaw that will raise the rack during the strike sequence. The
rubber bands serve in place of the final biasing springs At this point all of the levers
are temporary. Once the proof of concept and decorative design is complete, the actual,
steel parts will be fabricated and later heat-blued. The videos below show this operating.
First photo shows a close-up of the temporary seesaw device. One can see how this is
driven off the heat-shaped cam shown within the hour rack cutout. The next photo shows the
placement of the quarter rack.
The first photo shows the quarter strike seesaw. One can see that we intend to carry
through our bird design as applied within the escapement. Next we see how much of the rack
and strike lever components will be obscured by the tellurian dial.
This is the last photo of the clock before it is dismantled to cut the last remaining
plates consisting of the pendulum support brackets and the far right hand corner pillar.
That pillar is shown in the next photo being shaped to its final design. Next the
completed pendulum support structure. This was later redesigned to more closely follow the
shape of the antifriction wheel supports within the escapement.
The clock is next taken to pieces to attend to some housekeeping issues including
finding and correcting various tight spots. It now takes approximately three hours to tear
down the clock to this level and a similar amount of time to reconstruct. I think B now
understands John Harrison's travails with his repeated reassembly cycles during the
creation of H1! However, while this machine is much more complicated, we do have a bit of
an advantage over Mr. Harrison of nearly 275 years of technological advancements. But
still, at this level, it always comes down to precision hand-craftsmanship.
The movement is now reassembled and running. The front areas are now fully
skeletonized. Look carefully at the last photo. The overall design of the clock displays a
strong symmetry from left to right. However, look closely and you will see many subtle
variations. For example look at the lowest, inside branch of each corner pillar. Both hold
similar wheels but are completely different in shape from each other. The lower frame
structure reflects a classical design serving as the foundation. Moving upward it morphs
into the curvilinear organic forest of ivy shaped appendages supporting a forest of wheels
and visually stimulating mechanical fascinations. There is still a set of wheels contained
within an ivy shaped frame to travel across the front lentil supporting the escapement