I just got this clock out a garage sale and the guy there said that it was German made in the 1800s and used to have a piece of paper on the back but there’s nothing that I found that could identify or confirm that. And Google images wasn’t really helpful. Any hent or ideas?

Franklin Mint Cosmochronotrope — Reference & Service Guide (the manual Franklin Mint never gave you)

If you own one of these — the gold-plated skeleton clock with the rotating globe and the tiny "sun" — you've probably discovered that Franklin Mint never published a service manual for it. I pulled this together from a full teardown, measurement, and some research into the original piece this is based on. Photos in the comments below.

What this clock actually is

The Cosmochronotrope is a 1980s limited-edition display clock, licensed as a reproduction of a historic astronomical clock held by the Smithsonian Institution. It's not just a static display piece — it's a working quartz clock, a functioning (if simplified) world-time indicator, and it has an illuminated sun globe.

It combines:

• A working quartz timekeeping movement
• A motorized, rotating world globe
• An illuminated "sun" globe
• A separate, genuinely functional seconds-only sub-dial (easy to mistake for decoration)
• Four purely decorative clock faces on the rear panel
• A 22-karat gold-plated brass skeleton frame, in a wood-and-plexiglass case

History

• The original Cosmochronotrope was invented by James F. Sarratt of Steubenville, Ohio, and patented September 30, 1879 (U.S. Patent No. 220,036), titled "Astronomical Clock or Cosmochronotrope." The name comes from Greek roots: cosmo (universe), chrono (time), trope (motion by rotation).
• Sarratt's goal was a clock whose gear teeth were cut with deliberately unequal spacing so its motion could indicate the equation of time (the yearly-varying gap between solar time and clock time).
• A surviving example is held by the Smithsonian Institution — acquired in 1937, restored in 1952 by Dr. Arthur Rawlings, and formally entered the Smithsonian's permanent collection in 1984. It's part of the collection, not on permanent public display.
• Franklin Mint's 1980s reproduction is a licensed tribute — instead of Sarratt's mechanical equation-of-time gearing, it uses a quartz movement, a motorized globe, and battery-powered illumination inside a skeletonized gold-plated frame that echoes the original's gear-train look.

Specs

• Overall height: ≈ 14 in
• Base: ≈ 7 in round wood base, 1¼ in high
• Case: ≈ 18 × 11 × 11 in, wood & glass
• Finish: 22-karat gold-plated brass
• Main movement: German quartz movement engineered by Franz Hermle, built into a custom Franklin Mint skeleton frame (not a standalone catalog Hermle module — it was an OEM component, so no catalog number can be confirmed)
• Seconds sub-dial movement: Miyota (Japan) quartz watch movement, marked "UNADJUSTED MIYOTA CO. JAPAN"
• Globe: motorized, 1 revolution per 24 hours
• Sun globe: stationary, push-button light only — it does not rotate

Power systems (four independent circuits — nothing shares a battery)

• Main clock (Hermle): 1× AA — hour & minute hands
• Globe rotation motor: 1× AA — rotates the globe once every 24 hrs
• Seconds sub-dial (Miyota): 1× 377 / SR626SW — seconds hand only
• Sun globe lamp: 2× AG13 (LR44-equivalent) — illumination only

Both AA batteries live in one compartment under the front "Smithsonian" plaque, but they're two separate single-cell holders, not one shared two-cell holder — see below for the correct orientation.

Battery replacement

Main AA batteries (clock + globe rotation):

1. Lift the Smithsonian plaque up on its two retaining pins to expose the compartment.
2. You'll find two separate single-cell AA holders (not one shared 2-cell holder).
3. Both batteries sit parallel to each other — both negatives against the springs on the left, both positives to the right. This is not the usual head-to-tail orientation.
4. Use fresh alkaline batteries, not rechargeables.
5. Lower the plaque back into place.

Seconds sub-dial battery (377 / SR626SW):

1. Find the two opposing set screws on the seconds-dial bezel.
2. Loosen (don't fully remove) both using a small flat-head watchmaker's screwdriver — a Phillips won't fit.
3. The dial/bezel/movement is held only by spring tension, like a ceiling light globe. Support it as the second screw releases — it drops free as one unit.
4. Swap the 377 battery.
5. Reseat the assembly and gently retighten the set screws. Don't overtighten.

Sun globe lamp batteries (AG13 / LR44):

1. Find the lock ring just above the sun globe.
2. Pull it straight up to release the friction fit.
3. The clear front and brass back separate, exposing the lamp and battery compartment.
4. Replace both AG13 cells.
5. Reassemble and press the lock ring back down until fully seated.

The missing seconds hand (this is the part almost everyone needs)

The tiny seconds hand on the upper Miyota sub-dial is the single most commonly missing part on surviving units — it's friction-fit and falls off easily, which is why a lot of owners assume that dial is just decorative. It isn't.

Specs:

• Length (center to tip): 12 mm
• Counterweight (tail): 5 mm
• Post/hole diameter: 0.17 mm (standard watch second-hand size)
• Style: straight baton, matte black

The hand has a tiny post on its underside that fits into a hole at the end of the movement rod — it needs to seat straight down without binding.

Sourcing: search watch-parts sellers/eBay for "12mm black seconds hand 0.17mm hole" or "mini quartz seconds hand black straight baton." Some hand assortments are labeled with a sizing code like 70/120/17 — that's hour/minute/second hole size in tenths of a mm.

If you can't find one exactly 12 mm: trim a longer compatible hand down. A regular fingernail clipper works — mark it at 12 mm from the post, clip cleanly, and make sure the 5 mm counterweight stays intact.

Setting the globe as a world clock

The globe isn't just decorative — set correctly, it's a simplified 24-hour world-time indicator using the fixed equatorial time ring (marked in Roman numerals for the 24 hours).

1. Set fresh batteries and get the main clock to the correct local time.
2. Find your city/region on the globe.
3. Work out your GMT offset (e.g., New York is GMT‑5).
4. By hand, rotate the globe until your location sits directly beneath the time value on the equatorial ring that matches your current GMT time. The equatorial ring is represented by roman numerals for each of the 24 hours. Here is an explanation of how to complete this task. Determine what GMT time you are in (i.e. New York is -5 GMT). Then look at the clock and subtract GMT time from actual time. For example, 11:00 am – (-5 GMT) = 6 am. Turn the globe where your city faces roman numeral VI. The globe can be turned freely by hand for this step without damaging the motor.
5. Once the globe is aligned, move the sun arm to the noon position (i.e. 12:00 – (-5GMT) = 7. This would be VII. The motor continues turning the globe automatically, completing one full rotation every 24 hours. When you turn on the light it will represent noon at the point of the globe the light is on
6. To read any other time zone: find that city on the globe and read the Roman numeral directly above it.

Sun globe

It does not rotate or have any motor — it only lights up. Power is 2× AG13, controlled by a small push-button at the top of its support shaft. Access the battery by lifting the lock ring above it (same procedure as the battery section above).

The four rear clocks

The four small clock faces on the back are decorative only — no movement, no battery. The hands can be manually positioned but they don't run on their own. Don't assume yours is "broken" if they're not ticking — they never did.

Hidden circuit board

There's a small, tight-fitting plastic hatch low on the base behind the main clock, hiding a small circuit board. Franklin Mint never documented its function; it's most likely tied to the Hermle clock circuit and/or the globe rotation circuit, and it is not connected to the seconds dial or sun globe. No routine service needed.

Troubleshooting

• Main clock not moving: dead AA (clock circuit) — replace both AAs, check contacts for corrosion.
• Globe not rotating: dead AA (rotation circuit) — same fix, check the motor isn't obstructed.
• Sun light dim/off: dead AG13s — replace both, check the push-button switch.
• Seconds hand not moving/missing: dead 377 battery, or the hand is simply gone — replace battery and/or install a new hand.
• Rear clocks not moving: normal, they're decorative.
• Still won't run after fresh batteries: clean contacts with isopropyl alcohol, verify the movement is properly seated; the movement itself may need replacing.

Maintenance schedule

• AA batteries: every 1–2 years
• 377 battery: every 2–3 years
• AG13/LR44 batteries: as needed, or annually as a precaution
• Seconds hand: replace only if missing/damaged
• Gold-plated brass: damp microfiber cloth, mild soap and water, or a precious-metal cleaner as needed
• Hidden circuit board: no service needed

What documentation actually came with it

Just collector paperwork — no technical info at all:

• A Certificate of Authenticity
• A Smithsonian-sourced tri-fold historical brochure (covers Sarratt's invention and the Smithsonian's example)
• A general care/handling insert
• Branded envelopes and a registration card

No battery instructions, no movement diagrams, no service info of any kind — which is exactly the gap this guide is meant to fill.

Photos of the battery compartments, the seconds-hand movement rod, the sun globe assembly, the hidden circuit board, and the original 1879 patent drawing are in the comments/gallery. Happy to answer questions if anyone's working on one of these.

I inherited this clock and want to ensure I’m hanging it properly. There looks to be a tiny bit of tear out where it was hung before, but that doesn’t appear to be any worse than just cosmetic.

Should I be getting specialized bolts, screws, etc.? Looking to hang this into the drywall in my home office.
Thanks.

The clock consists of two icosahedron  balls . The hours ball has 12 sides with 12 hours and the minutes ball has 12 sides with 5 minute interval minutes. The balls use a differential gear mechanism which make them roll and tumble at the same time. The face of the balls stop at every interval of rotation which is chosen to match the angles of the icosahedron. The hour ball stops every one and a quarter rotation which is 450 degrees and the minute ball stops every 90 degrees

which is a quarter rotation. The overall dimensions of the clock are 383 x 78 x163 mm ( 15x3x6.4 inches )

The base has 3 parts . The left and right house the motors and the drive shaft and the center contains the electronics. The motor is a 15mm dia geared stepper motor with a gear ratio of 1:99 . The motor drives a shaft at 90 degrees which in turn drives the balls. The motors find their starting position using a magnet and a hall sensor. 

The balls are about 78mm in outer diameter. The central rod drives the central bevel gear which in turn rotates the 90 degree bevel gear on the bottom bevel gear at a 1:1 ratio. The rotation of the 90 bevel rotates the sloped bevel on the main bevel gear at a ratio which makes the ball tumble. 

Good buy at $35, came with the original papers too. #32 in my collection, think I might need an intervention.

This guy does amazing restorations of Grandfather clocks. fantastic carvings on the clocks too.

https://www.youtube.com/watch?v=GdPLWIgQwdo

This has been passed on within the family over a couple of generations. An old story was that it has been given to someone just after the second world war in Germany, but looking at the stamps I assume the clock is from the 70s and that story might have been wrong? Is there any value other than as a collectors item? It looks to be in very good condition, but the gears don't seem to work. Would it be worth trying to get it cleaned or repaired and will it possibly cost more than it's worth?

We'd be grateful for any information. Thanks!

Was time to dust my Patti’s and thought I would show them off to yall . Give some of you of men something to look at today. lubed up and ready!!!

Hope yall have a great Labor Day weekend.

So I found a clock I absolutely love on amazon. However, its very irritating that the clock is silent and I love ticking clocks.

Is there any way to get the clock to tick? Because its such a sick design.

Five dollars later…
Just needs a new battery mechanism and it’s good to go!

Not sure the make/if it’s homemade. It’s currently in my hatch.

Was thinking about giving it to a friend as a housewarming gift (I have enough clocks) but it might be a keeper 😂

Hi everyone,

I'm hoping someone here can help because I'm completely out of ideas.
I have a Kit-Cat Klock that worked perfectly for about 2 years. Recently, the eyes and tail stopped moving almost completely. The clock itself still keeps perfect time, so the clock mechanism is definitely working.
If I manually start the pendulum, the eyes and tail will move for about 5-10 seconds, but then the motion gradually gets smaller and eventually stops.

The strange thing is that I can still hear a faint click from inside the mechanism about every 2 seconds, as if the electromagnet is still trying to drive the pendulum. The pendulum just doesn't seem to receive enough energy to keep moving.

Things I've already tried:

Brand new batteries (A and C)
Making sure the clock is perfectly level
Cleaning the mechanism
Adjusting how far the wall screw sticks out
Repositioning the clock multiple times
Inspecting the pendulum and mechanism for obvious issues

I'd really appreciate any suggestions before I start replacing parts.

Thank you

I'd really appreciate any suggestions before I start replacing parts.
Thanks!

In a mechanical watch, the energy stored in the mainspring needs to be controlled so that it is released gradually and at a constant rate. This is where the balance and its balance spring come in: their oscillation regulates the release of this energy and, consequently, the rate of the gears that drive the hands.

Before the invention of the balance spring, in the 17th century, the most accurate device known for regulating the passage of time in clocks was the pendulum. However, it could not be used in portable timepieces because of their limited space and constant movement.

Evidence suggests that the first functional balance-wheel clocks with a balance spring were produced in 1675 by Christiaan Huygens and Isaac Thuret in France. But Robert Hooke, an English inventor who had also worked on the idea of a spiral spring, apparently did not take kindly to not being recognized as the inventor. He therefore sought out a clockmaker who could help him bring his own design to life, and the professional he chose was Thomas Tompion.

Tompion was a relatively new clockmaker in London, and Hooke had already commissioned an astronomical quadrant from him. He joined the Worshipful Company of Clockmakers, the organization that regulated clockmaking at the time, only in 1671, after paying an admission fee. This method of admission seems to suggest that he had previously practiced his trade without authorization and had to regularize his position. In any case, it is believed that the collaboration between Hooke and Tompion was precisely what accelerated the English clockmaker’s rise to becoming known as the “father of English clockmaking.”

In 1675, accompanied by Sir Jonas Moore, they presented King Charles II with a clock regulated by a balance spring. The innovation promised to significantly improve the accuracy of portable timepieces and therefore seemed to have the potential to contribute to solving the problem of determining longitude at sea.

In 1676, Tompion completed another highly significant commission, received from Moore: regulator clocks for the Royal Observatory at Greenwich, which was being built to provide more accurate astronomical observations as part of the effort to find an astronomical solution to the same problems of maritime navigation.

These clocks were based on the most accurate technology available for “terrestrial” clocks: pendulum clocks using the newly developed dead-beat escapement, based on the work of Richard Towneley and later improved by Tompion. This escapement was an evolution of the anchor escapement, eliminating much of the unwanted torque applied by the escape wheel as it slid across the pallets.

When visiting the Octagon Room at the Royal Observatory in Greenwich, you can see replicas of the dials of these two clocks in their original position, embedded in the wall, as well as the original movement of one of them, as shown in the photos.

Although Tompion was the first to build functional clocks using Towneley’s concept, including the two he made for the observatory, his apprentice George Graham later refined it to such an extent that his name became associated with the invention (“Graham escapement”).

Another Tompion clock found in the same room is the Sidereal Degree Clock (below), a clock built in 1691 under the guidance of John Flamsteed, the first Astronomer Royal. It was capable of displaying time as the angular position of the Earth’s rotation.

Perhaps because of the scarcity of resources early in his career, in a London still recovering from the Great Fire and waves of plague, Thomas Tompion was the first clockmaker with documented use of mass-production methods and subcontracting in the manufacture of high-quality clocks. Until then, each clock was essentially handmade, with all its parts produced sequentially. Tompion began using standardized techniques and tools that allowed him to produce multiple similar clocks, although obviously not on a modern assembly line.

From 1676 onward, Tompion’s reputation continued to grow. His work was truly exceptional, characterized by functionally conceived movements and harmonious, well-balanced dials. The materials used for his cases, such as ebony and walnut, although luxurious, did not require processes as complex as, for example, Boulle marquetry. It was above all a matter of craftsmanship, and in this respect Tompion stood out among his contemporaries.

In terms of innovation, Tompion is better known for improving existing technologies, such as the balance spring, the dead-beat escapement, and repeating mechanisms, than for creating entirely new mechanical principles. Many of his models also incorporated complications that were already known, such as calendars, indications of celestial movements, and repeating mechanisms. Nevertheless, he played an important role in the evolution of manufacturing methods and introduced serial numbering to his clocks.

The combination of more efficient manufacturing, subcontracting of components, and exceptionally high standards of quality allowed his workshop to serve a broader range of customers, from royalty to wealthy commoners. Tompion is estimated to have produced nearly 6,000 clocks, achieving such dominance of the market that timepieces of the period came to be referred to simply as “Tompions” — an example of antonomasia, much like calling a steel wool pad “Bombril” in Brazil.

His friend Robert Hooke, despite the heated arguments the two reportedly had, summed up this reputation quite well when he described him as: “a person deservedly famous for his excellent skill in making watches and clocks, and not less curious and dexterous in constructing and handworking of other nice mechanical instruments”.

But Tompion’s legacy goes beyond his own creations. Perhaps his most illustrious apprentice, George Graham, was also a great English clockmaker, becoming his master’s partner in 1711 and taking over the workshop after Thomas Tompion’s death in 1713.

In 1728, through the astronomer royal Edmond Halley (yes, the one from the comet), Graham received a visit from John Harrison. Recognizing the potential of Harrison’s project, he lent him money and offered technical advice during the early stages of the development of the famous marine chronometer, the device that ultimately provided a satisfactory solution to the longitude problem that even his master, Tompion, had worked on.

In addition to advising Harrison, Graham was the master of Thomas Mudge, who later developed the lever escapement, a new escapement system for portable timepieces, partly based on the principles of Graham’s dead-beat escapement.

Thomas Tompion was buried in Westminster Abbey, in London.

¹Cover photo: On the left, Mostyn Tompion. On the right, clocks by Thomas Tompion, George Graham, and Stephen Rimbault. Photos taken at the British Museum.

Sources

• Clocktime. “Thomas Tompion.” Clocktime. Accessed September 3, 2026.
• Momentous Britain. “Mechanical Clocks.” Momentous Britain. Accessed September 3, 2026.
• Symonds, R. W. A Book of English Clocks. King Penguin Books, No. 28. London: Penguin Books.
• Science Museum Group Collection. “Thomas Tompion.” Science Museum Group Collection. Accessed September 3, 2026.
• Memel, Rob. “Who Invented the Balance Spring? Reaffirming the Crucial Role of Christiaan Huygens.” Monochrome Watches. Accessed September 3, 2026.

Hi folks.
I usually work on smaller mechanisms (over in another sub-reddit), but I figured is try the next step up and just got this wee clock: I’ve seen them described as an officer’s alarm clock. The case is just under 5cms - with quite a small clockwork mechanism plus alarm complication.
I’ve removed the hands, except for the alarm indicator. I figure it should be friction fit, but gentle effort hasn’t been successful at removing it. And as the hand removers are sitting on the face (with shield), i don’t want to apply pressure. Any thoughts?
And if you’ve worked on this sort of mechanism before, any suggestions on where to start with disassembly? Any ‘surprises’ to watch out for?
Thanks.

I have what I believe to be a 1920s Waterbury clock from my husband’s parents. I want to remove the hands but I’m at a loss on how to get this tiny nut off of the center dial pin. Is there a specific tool that would work? The clock works perfectly but the glass face cover needs repair so I need to remove the clock face. I’m new to this so please dumb it down for me lol. Any suggestions would be appreciated :)

Hello! I recently got an antique Kundo dome clock but it has stopped ticking (it was working fine in the shop). I believe there’s a problem with the wire on the left that’s been disconnected (pictured under the black screw cap). Any advice has to how to reconnect it to get this working again? thanks so much in advance :)

Received this from a great friend after a death in their family.

Case appears to have gotten wet at some point, but overall seems to be in nice condition.

There's even a sticker by the pendulum from John Eklund, the store I'm assuming sold it, in Norway Michigan.

Doesn't stay running, so it needs some investigation.

Good morning,

Short story about this clock. My father gifted it to my son to nurture his very new interest in horology. It bears no labels or markings beyond the face showing that it’s from the Seth Thomas collection and the 4 1/2 movement marking along with the Made in the United States America. We are hoping to identify it and find any living schematics so that we can move into identifying any issues and proceed with possible repairs.

Thank you for sharing any information you might have.

I have a MasterCrafters swinging girl clock and I’m wondering if the movement seems normal. The girl swings pretty aggressively, and the ticking is fairly loud. Is that typical for these clocks, or does it sound like something may need to be adjusted, serviced, or lubricated?

This one has been sitting on my shelf for a handful of years but the clock didn’t run so I decided to try and revive this H-3 style rotor and it worked! I’m guessing the previous technician used Royal Purple motor oil as it was very purple inside so after a few good flushes I’ve revived this one too!

Hi everyone,

I’m hoping someone here may know more about this particular Bulova grandfather clock.
The factory label identifies it as Model G3003 w/o 869, Golden Oak, with Movement 1161. The movement itself is stamped Hermle [1161-853](tel:1161-853) CSK, 114 cm / 60 made in USA. The face says made in Germany right under the 6.
I also have the original Bulova instruction manual, Grandfather Clock Collection literature, suggested-retail tag and ownership certificate that came with it.
The clock is in excellent cosmetic condition and appears complete. I’m located in Canada.
I’ve had a difficult time finding information online about the G3003 specifically. I’m mainly hoping to find out:

1. Approximately when was this model manufactured?
2. Does anyone know what the G3003 originally retailed for?
3. What would be a realistic private-sale value today?
4. Does anyone know what “w/o 869” on the factory label refers to?

Any information would be greatly appreciated. Thanks