Reassembly of clock base frame - December 2019

This month Buchanan reassembles the base frame of the clock after final polishing and where feasible, lacquering. Within the frame are the clock's spring-driven main wheels, state of wind indicators and the two Fasoldt-style quarter and hour strike flies.  

Buchanan writes: Yesterday I made the retainers for the band springs. The hooks came loose far too easily when working on the springs, so once the hooks are in place the little angle is inserted and the hooks are locked in place. I did this while reassembling the clock to check all the spring clearances. I am very happy to say the springs work very well in every respect. Not physical clashes anywhere.

I reply: Glad to see this. Fixing this issue is a great example of what would avoid a nightmare for me where I do not have the experience to solve the problem over here.

Here Buchanan begins to design and build the demo select drive lever. This is the controller for the dual speed transmission that selects from normal clock operation to the demonstration mode that has a normal (slow) demonstration where each revolution of the demonstration crank equals one day and, fast, which is ten times faster to demonstrate only the orrery, this is needed as the outer planets of Jupiter and Saturn make an orbit around the Sun in 11.86 years and 29.5 years and turning the regular demo crank of one revolution per day would produce a negligible effect on the motions of these two planets.

The select lever is in place, second photo. The Allen screws for the support bearing block are temporary.

This component will though the movement of the rack, allow the operator to switch between two speeds for the celestial demonstration.

These are the last 40 parts of the lower frame (main wheel base frame) polished and lacquered. The bearing blocks will also be numbered for proper fit. The logo is stamped on the rear.

These two photos show all of the lower frame components (excepting the strike fly fans and speed selector and lever).

These two photos show the rear and front base frame pillars. The rear pillars have the stop work and state of wind, evidenced by the Geneva cams and the snail cams mounted to the drive wheels. The front pillars have the state of wind dial work and pivots for the dial hands. The rest of the clock is supported upon these pillars.

Rear pillar with Geneva and snail cams for stop work and state of wind indicators.

This video demonstrates the ceramic bearings used throughout the project. They offer superior performance to conventional metal bearings by having very low friction. They can also be used with minimal or no oil, thus eliminating the most common source of problems in clock making, the failure of oil by drying out or attracting dirt within the pivot. All of the bearings are of the 'shielded' variety that resist dirt infiltration. In addition most have a decorative plastic red ring covering the exterior side that further reduces infiltration. These rings are made to match those pivots that have real jeweled pivot holes. The other side of the bearing is housed in a countersunk hole in which it is mounted offering the same dirt resistance as the ring on the outside. About half the pivots in the machine are bearings the rest are jeweled.

Before polishing, it was difficult to discern the pink color of the bronze wheelwork from those made of brass, but after the polish one can see the beautiful color contract. The idea was from an exhibition tower clock by Edward Dent.

These are the state of wind components that reside within the inside perimeter of the frame. The oddly shaped counterweights are an octagonal shape based on counterweights on a clock I have by Bernard-Henri Wagner, c. 1886. This same shape is also used on the counterweights for the dual Wagner rocking frame remontoire used in the time train. We have dubbed them “footballs” because of the resemblance to the ball used in what we call in the United States as football. The rest of the world refers to Soccer, as football using a spherical ball.

The second photo shows the blued follower arms that will ride along a cam to produce the dial output for the state of wind indicators. These are about 4” (10cm) long and are perfectly blued. This is an application where Buchanan’s furnace really come in handy. Bluing such a large piece over an open flame, or even using a pan with brass filings would take far longer and without much patience and luck would not produce the perfect uniform color throughout the part we see here, and unlike a clock hand which is rather thin, these have quite a bit of mass making the bluing process by conventional means that much more difficult, furthermore, Buchanan is convinced that a long slow cook in the oven produces a superior blue color to the quick heat gun or open flame methods.

Uniformity of color doesn't get better than this.

The spring material for the main barrel clicks gave a surprising color when put into the bluing oven. Instead of a deep blue we got a purplish color. This was not because we stopped the bluing at that color, which is possible on conventional steel. This color was the end product until “going too far” where the color becomes dull. I decided to go with it rather than steel as it looked interesting and added another color to the mix.

This photo shows the beauty of Buchanan’s design, the oversized curvilinear click springs, rosettes and the combination of five colors all within this one small assembly. Notice that the clicks do not seat within the ratchet wheel identically. The one at the 10 o’clock position is fully seated while the one at the 4 o’clock is almost out of position. This is intentional so as to provide an audible “click clack” as the clock is wound. This was inspired by another clock in my collection, a Dent exhibition clock, c. 1852. 

Buchanan now begins the parts count so as the clock is undergoing final finishing and reassembly a tally will be made of the various parts. Initial count 722.

The clock base frame has gone through final polishing and where feasible, lacquering. This video shows the reassembly of the frame, state of wind indicators and spring-powered main wheels.

These two photos, above, are the strike fly components undergoing final finishing. 

Buchanan has finished the Fasoldt fly fans. These include three style of toothed wheels, conventional, bevel and internally toothed, allowing for a tourbillion looking epicyclical movement. The stainless steel frames have been shaped to accentuate their sinuous design, the fly fans sport a complex decorative shield. The left assembly looks to be much taller than the one on the right. This is not an illusion. The wheel and the whip detent darts in and out tracing out a five lobed pattern as it rotates within the internally toothed wheel. The left assembly is 'standing' and the one to the right is 'sitting'. See illustration below.

The fly fan in full 'sitting' position.

Second parts count. 884.

The fly fan installed on the left side, hour strike.

This fly is on the right hand side for the quarter strike. What I like about this photo are the background sun and planet gears of the epicyclical winding system of the two main wheels in the background. They seems to mirror each other giving a "fun house" carnival mirror effect. It's nearly impossible to make heads or tails of the mechanism. Nice!

Front three-quarter view of the completed base. 

Rear three-quarter view of the completed base.

The two photos above highlight the finished base. It is not as obvious in the first photo as the next one the contrast between the polished base and the untouched components mounted to it.

In this photo one can see the difference in the finish between the lower base frame corner member and the strike frame corner mounted directly above. The frame holding the bells has the same duller finish, it appears Buchanan has polished the bells.

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The following will be of interest to some of the more technically oriented. I have been asked this question a few times before as to the types of materials we have used in the project.

Comliment of ball bearings used:

Hybrid stainless steel ball race and ceramic balls. Above is an old photo of the sizes commonly used in the project. Note the photo was taken in October of 2010 and these were of the common steel type; which has been replaced with the sheilded, hybrid ceramic type. Sheilded bearings offer very good dust protection without adding to friction. There are a few other sizes and customized types used in a few limited areas.

The left photo from July 2008 shows the original compliment of jewels in three sizes. Each tray holds 100 for a total of 450. A few dozen have been bought since. The second photo from December of 2007 shows automotive high grade red plastic to cover ball bearings; designed to match the color of the jeweled bearings used elsewhere. Where an arbor runs past the edge of the bearing a ring is used, where it does not  a cap jewel look is needed and they are the dome shaped pieces. These also serve as an excellent dust barrier. Pivots in the machine are about evenly divided between ball bearing and jewel types.

Brass:

The type of brass we use is CZ121 or CZ 120 depending on sheet or rod but basically a leaded free machining engravers brass.

The screw steel is grade 1045:

1045 is a medium tensile low hardenability carbon steel generally supplied in the black hot rolled or occasionally in the normalized condition, with a typical tensile strength range 570 - 700 Mpa and Brinell hardness range 170 - 210 in either condition. Characterized by fairly good strength and impact properties, plus good machinability and reasonable weldability in the hot rolled or normalized condition.

1045 has a low through hardening capability with sections up to around 60mm only generally recommended as suitable for through hardening and tempering. It can however be successfully flame or induction hardened in the as rolled or normalized condition resulting in surface harnesses of up to Rc 54 - Rc 60 depending upon quenching medium employed, type of set up, section size etc. Core strengths will remain as supplied.

It does not however respond satisfactorily to nitriding due to a lack of suitable alloying elements.

1045 is used extensively by all industry sectors for applications requiring more strength and wear resistance than the low carbon mild steels can provide and the higher strength of the low alloy high tensile steels is not necessary, plus those applications requiring flame or induction hardening.

Typical applications are: Axles Various, Bolts, Connecting Rods, Hydraulic Clamps and Rams, Pins Various, Rolls Various, Studs, Shafts, Spindles etc.

Stainless steel used in high wear positions is Stavex:

Uddeholm Stavax ESR is a premium grade stainless tool steel with the following properties: • good corrosion resistance • excellent polishability • good wear resistance • good machinability • good stability in hardening. The combination of these properties gives a steel with outstanding production performance.

Non stressed parts are made out of 316 stainless steel;

Alloy 316/316L is molybdenum-bearing austenitic stainless steel. The higher nickel and molybdenum content in this grade allows it to demonstrate better overall corrosion resistant properties than 304, especially with regard to pitting and crevice corrosion in chloride environments.

The balance spring material is Ni Span C 902:

Materials notes: A nickel-iron-chromium alloy made precipitation hardenable by additions of aluminum and titanium. The titanium content also helps provide a controllable thermoelastic coefficient, which is the alloy's outstanding characteristic. The alloy can be processed to have a constant modulus of elasticity at temperatures from -50°F to 150°F (-45 to 65°C). Used for precision springs, mechanical resonators, and other precision elastic components. Standard product forms are round, strip, tube, pipe, and wire.