Fabricate movement stand, inner steel structure - October 2012
Depicted above is a
drawing for the clock stand Buchanan had submitted in September 2009,
shortly after the redesign of the clock frame from the original plate and
spacer to the current pillar frame configuration. He had anticipated at that
time that the new frame design with its long narrow base would not be
sufficiently ridged to avoid the various stresses in the base structure from
the weights to prevent a shift in the pillar uprights which would cause the
wheels to bind. This is easy to imagine if one thinks about the base
deflecting downward from the mass of the clock weights and all of the long,
upright pillars that contain the wheel works being pushed inward toward each
other from that deflection. It is a
tribute to Buchanan in that these issues were anticipated long before the
actual article was made.
Next I began to get
some detailed photos of the steel stand that will hold the clock. It is
built to withstand any ‘racking’ that could occur from an uneven floor as
well as from the winding process and the combined mass of the clock and its
four weights. Any unevenness transmitted to the clock base frame will result
in slight distortion of that base frame and when translated and magnified
through to the long upright frames that hold the movement’s wheel works, the
clock will cease to function because of the change in tolerance between the
wheels from frame to frame. In short –a binding between the mating wheels.
From the first two photos it looks like Buchanan is using the same type of
angle iron that is used to hold a course of exterior brick work over a
window, in other words a lintel. The angle stock is about 1/8” thick.e
third photo shows
the table top of the stand's structural ‘box frame’ being built up.
The interior cells serve as additional stiffeners for the platform that will
serve as the base to support the clock frame. The second photo shows a
detail of one of the numerous welds. Next the entire base before the welds
are ground flush to the surface.
These photos show the
with all of the welds ground flush and
next to the clock .
This series of six
photos show the beginnings of the system to allow a limited degree of
mobility to the entire clock. This is necessary, since without this ability
the clock would have to be removed from the stand to have any hope of two
people being able to move it even with the weights removed. This would be
too dangerous except in the contingency of it needing to be relocated to
another place entirely. But for the purposes of being able to move the clock
to clean, or make changes to the floor or carpet that it may be standing on,
or to move to another location within the same area, another way has to be
found to allow it to have limited mobility without the need to remove the
clock from its stand. These photos show a wheel mounted to an assembly that
will allow them to be fully retractable. In this way the weight of the clock
will only be borne by the wheels when they are in actual use. The rest of
the time the weight is transmitted to the floor directly through the frame
threaded rod is welded to a toothed cog wheel and is shown in the first and
photos. The third and fourth photos show the rod inserted into a mating,
threaded hollow tube which, in turn is welded to a plate that will become
part of the base of the clock stand. In this way, when the cog wheel is
driven in forward or reverse, the wheel will extend or retract.
The stand legs are being fabricated in the first two photos.
Next photo shows the various components assembled to fabricate the stand
The first two photos
show the intricate clamping needed to assemble the metal box that surrounds
the threaded rod and cog wheel that is involved with the retractable wheels.
The assembly is now ready for welding.
The four individual boxes are now welded as seen in the last photo.
Next the lower frame cross members are
assembled and in the next photos welded into place onto the four corner boxes
containing the wheel retraction assemblies. It should be noted that the
uprights are not welded to these same boxes, but are held by an internal
treaded rod; allowing for the disassembly of the stand.
This series of six
photos show the fabrication of the upper stand which will support the clock
base. The third photo shows one of three attachment points between the clock
stand and the actual clock base support as represented by the silver box
with the four openings which are there to allow the weight lines to pass
from the clock to the drive weights below, fourth photo. These points are
not solidly attached but allow for some flexing between the rest of the
frame and the central box base that supports the clock. In this way any
uneven floor that the stand might encounter is corrected by this
arrangement. The fifth photo shows the three attachment points with the last
having the central box mounted in place.
Further photos of the stand fabrication. The first two photos show the
threaded rods which are inserted into the metal tubes that will serve as the
legs of the stand. These will be used to snug down tightly the tubes to both
the lower and upper sections of the clock stand.
The next photo show a close up of one of the three attachment points
for the clock support bed to the rest of the stand as outlined in Buchanan’s
original drawing of September 2009.
This photo shows the
clock on its temporary stand next to the permanent stand being fabricated.
Note the completed Pouvillon astronomical clock being readied for delivery
in the background.
The next photo shows
another of the three attachment points for the clock support bed to the rest
of the stand. To be honest, I think that given the robust construction of this entire
assembly, the stand would be so rigid as to not have the need for the three
attachment points in the first place, but we are going the 'extra mile' as
always in this project. The last photo shows the eight points that will
ultimately contact the clock base to keep it perfectly level. They are
located directly beneath each winding drum for maximum support. The assembly
is attached the milling machine to plane them down to make all of these
attachment points perfectly level.
The central box is now in place upon the three attachment points within the
upper stand table. The eight holes will each receive a pin that will mate
with a hole drilled into the clock base. These pins are just the right
length to hold clock imperceptibly above what will later be the decorative
wood surface that will cover this area.
The entire structure is coated with a rust inhibitor.
Notice that the clock is now disassembled to its main subassemblies. We are
now beginning to replace the original ball bearings with the updated ceramic
variety to achieve our goal of making this clock a 'dry runner'.
The next two photos show the gear box with crank in place that will drive
the bicycle chain connected to all four retractable wheels.
Next is a close up of the chain drive from the side that is affixed to
the base of the clock stand through the four bolts shown.
Next a view from the
front edge. Next a view of one of the four corners that the chain
circumscribes and meshes with the gear cogs that will move the stand’s
wheels. This system allows for the uniform raising and lowering of all four
wheels simultaneously so that the stand is perfectly level at all times.
Finally, a view of one of the
corners; here we see the wheel extended with the stand foot just off the
We see now that Buchanan is not only an
expert clockmaker but iron worker as well! The entire structure will
be clothed in a wood exterior and decorated with ormolu appliqués.