Clock books added to the library

Whether you are working on your first clock movement or have repaired dozens, resources, I believe, are essential. There is only so much information gained from a YouTube video, antique clock information site or how-to instructional resources online. Sadly some information is just plain wrong.

There comes a point in time when you simply must have more detailed information that one can reference without painstakingly plowing through a frustrating Google search.

Opinions vary as to what constitutes an essential clock repair library but I believe a combination of instructional manuals, clock identification guides, and historical horology should be at the heart of any clock library.

I will begin with what I determine to be essential resources and additional resources I have recently added to my library.

But first, here are a few I recommend.

My go-to set of books for American clocks is a series of working manuals authored by Steven G. Conover.

Working with Anniversary or 400-day clocks requires the Horolvar 400-day Clock Repair Guide. 400-day clocks can be quite finicky and you are asking for trouble if you do not have this resource. The perfect companion is Mervyn Passmore’s book entitled Anniversary Clock Adjusting. It is a little short on depth but simple and to the point.

Next are three books by Philip E. Balcome.

The Clock Book – An Overview of Heirloom and Contemporary Clocks in the American Home (not a repair book per se but a guide to identifying clock parts, types, styles, and trends)
The Clock Repair First Reader – Second Steps for the Beginner
The Clock Repair Primer – The Beginners Handbook

Balcome books are easy reads and are targeted at beginners and more advanced repairers.

John Plewes focuses on Canadian Made clocks. This is a good how-to manual though not as detailed as the Conover books mentioned above.

Now, for my newest books and how I came to be in possession of them.

The Heritage Clock shop in Brockville, Ontario went out of business on May 28, 2022, after 29 years of serving the community of clock lovers. There is a chance that new owners will step in but not yet, so far. Sadly many of these mom-and-pop shops have now disappeared and with it the knowledge and expertise of antique and vintage clocks.

My newest collection of books is as follows. The photos should be self-explanatory.

_{A good source of historical background information}

_{Limited use but I might regret throwing these away some day}

_{Perhaps the best books of the new bunch}

_{Good information from the two Candain books on the left}

Fortunately, a member of the Ottawa Valley Watch and Clock club was able to pick up the books which were free to a good home. Naturally, that person selected what they wanted and passed the remainder to me through another member.

Most of the books are price guides from the 1980s and 90s though some are helpful guides and manuals. The estimated values of the clocks in the identification guides are outdated as clock prices have dropped precipitously in the past decade but they provide a handy resource for types and models from various manufacturers.

Most of my work up to now has been with American and Canadian clocks, though some are German, French, and of course, British.

What I am missing are instructional manuals for foreign clocks (French, German, etc.), and historical information for Canadian Clock companies. The new books I have brought into my collection do not address this issue but if one is in the process of expanding a clock library it is always a work in progress.

September 26, 2022

Anniversary clock repair – a replacement suspension spring

Let me start by saying that opinions on torsion clocks are divided—some people have great success with them, while others absolutely loathe them. Despite their seemingly simple design, they can cause endless frustration, which is why many clock repairers tend to avoid them. Fortunately, I seem to be one of the lucky ones.

Kundo standard size 400 day clock — _The _{Kundo Standard size 400-day clock wound once per year}

I gifted this clock to my daughter three years ago. She chose it for its intriguing visible movement and the convenience of running an entire year without winding. Recently, she moved across the country, and during the relocation, the clock “broke.” “Can you fix it, Dad?” she asked. “Leave it with me,” I replied.

400-day clocks, also known as torsion clocks, have been around for over a century. They were first produced in limited numbers in the mid-1890s, but their popularity surged after 1900. Between then and the 1980s, thousands were manufactured, becoming a favorite choice for wedding and retirement gifts—hence the nickname “anniversary clock.”

The Kundo model featured here dates back to the late 1950s or 1960s, during the height of production. However, with the advent of quartz clocks, mechanical versions quickly fell out of favor.

Kundo is a well-known name in the world of anniversary clocks. The name is a combination of Kieninger and Obergfell, a highly respected German company. Today, the company continues as Kieninger, operating as a subsidiary of Howard Miller USA.

Dial face Kundo Clock — _{Dial face, Kundo Clock}

Servicing a 400-day Clock

To service a 400-day clock, I highly recommend using the Horolovar 400-Day Repair Guide as a reference. Can you repair a 400-day clock without it? Yes, but the Horolovar guide eliminates almost all the guesswork.

This particular 400-day clock is a Kundo Standard 53, which requires a .0032″ (0.081mm) Horolovar spring. If you don’t have the time or tools to assemble the suspension units yourself, Horolovar (or most clock suppliers) offers fully assembled units. However, these come at a significantly higher cost.

Section 10 of the Horolovar guide includes templates for various clocks. These templates provide precise patterns for positioning the fork and attaching the upper and lower blocks to the suspension wire, ensuring proper assembly.

suspension spring installed on a Kern — _{The suspension spring assembly includes the top and bottom block plus the fork}

The screws on the suspension assembly are very small, so using a high-quality precision screwdriver is essential to avoid damaging them. The suspension spring is longer than needed and will require trimming to fit. Once the spring is securely attached to the fork and blocks, it’s ready to be reinstalled onto the movement.

The suspension spring assembly hooks onto the top cock and bottom weights or balls. A threaded thumbscrew on the top base slips into the top block. The bottom block has two pins to which the pendulum hangs. Next are the back spring cover and the locking guard.

Torsion clocks have pendulum locking systems that must be engaged even when the clock is moved just a few feet. Often, the result of an unlocked clock is a broken suspension spring. The locking guard on this clock is an earlier design and looks pretty flimsy in my view but it should work.

Once the spring assembly is installed on the movement it is time to test the beat. The beat should be 8 beats per minute and there should be ample overswing in both directions. A 270-degree rotation is healthy enough.

What makes the 400-day anniversary clock a great addition to a collection?

They are:

Relatively inexpensive to buy, although some models like Schatz and Gustav Becker are more sought-after and therefore more expensive.
Very quiet in operation.
Easy to disassemble, clean, and reassemble due to having few parts.
Slow runners, meaning wear is rarely an issue.
A fantastic conversation piece.
Long runners, with some lasting 400 days or more on a single wind.

What makes them less ideal:

Notoriously inaccurate timekeepers.
Can be frustrating to fine-tune at times.

Since I had previously serviced this clock, I was able to loosen the tiny screws on the blocks and fork with ease. Sometimes they can be tight and difficult to remove, but on this occasion, everything went smoothly. As of this writing, the clock has been running well for several weeks.

While it’s currently running slightly fast, small adjustments to the regulating dial will slow it down. However, there’s a limit to how much you can adjust, and it’s not a clock I would rely on for precise timekeeping.

December 7, 2020

Horolovar guide and how to determine the correct suspension spring for a 400 day clock

A 400-day clock, also known as a torsion clock, is a type of mechanical clock designed to run for about a year (400 days) on a single winding. It features a unique suspension system, where a rotating pendulum or torsion spring controls the movement. The clock’s long running time is achieved through a very slow, consistent release of energy from the mainspring, and the mechanism is typically enclosed in a glass dome for display. Though not particularly accurate they are fascinating to watch.

Years ago my daughter gave me a Horolovar guide as a Christmas gift. Any horologist will agree that the Horolovar guide is an indispensable guide when working with 400-day clocks.

It is not a manual one opens up regularly but when working on 400-day or anniversary clocks, as they are often called, it is an absolute necessity.

The guide was last published in June 1991, and I believe little has changed since then, as I’m unaware of any mechanical anniversary clocks still in production today.

Using the Manual

My daughter was in the midst of moving across the country when she unknowingly overlooked the locking mechanism on the 400-day clock she had received as a gift a few years ago. Upon unpacking it, she found that the suspension spring had snapped. While a snapped suspension spring can’t be reused, it can be easily replaced.

400-day clocks require very specific suspension springs, ones specially designed for each of the many dozens of manufacturers in the past 100 years. Install a suspension spring with an incorrect thickness and length and you are asking for trouble. The correct spring for the make and model of the clock will ensure a smooth-running anniversary clock that will operate for many years.

On the positive side, these clocks run so slowly at 8 beats per minute that it is rare to have worn pivots and bushing holes.

Back to the clock in question. It is a Kundo anniversary clock made in the 1950s. According to the Horolovar guide, it is model 1371. Model 1371 tells me that the thickness of the suspension spring is .081 mm or .0032″. I’ve worked on similar models before and had some leftover Horolovar suspension springs of that size.

_{Kundo 400-day clock, made in West Germany}

This is essentially a one-hour job. There are two blocks, one at the top and one at the bottom. Carefully unscrew the blocks, ensuring the spring doesn’t become bent during the process (the small screws can be tricky to loosen). Once the blocks are removed, insert the suspension spring and tighten the screws. After securing the blocks, the manual will indicate where to attach the suspension fork.

Install the assembly onto the clock by attaching the top block with a screw that threads into a hole and hooking the bottom block onto the pendulum but your work is not finished.

Now comes adjusting the beat and regulating the clock. There is a bracket above the suspension spring assembly that can be turned slightly (it is a friction fit) in either direction to correct the beat. I set the beat by ear and eye but there is a beat setting tool that can be purchased from a clock supplier if you plan to work on a lot of these clocks. In any event, a beat amplifier is an absolute must.

Most 400-day clocks run at 8 beats per minute. Mine runs slightly faster at 9 beats per minute, but this can be adjusted using the dial-type speed regulator at the top of the four weights. While a clock running a bit fast might seem negligible, over the course of a year, it can accumulate into a significant difference of minutes or even hours. As anyone familiar with these clocks will attest, they are not known for their precision in keeping time.

Can you install a new suspension spring without the Horolovar guide? Yes, but you’ll need to research the correct suspension spring thickness for that specific model and use the old assembly as a template.

That said, it’s much easier to simply buy the guide—it eliminates all the guesswork.

October 1, 2020

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Servicing a 400-day Clock

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Using the Manual

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