German Box Clock Restoration | A Family Heirloom

When my wife’s parents sold their home in a small town in Nova Scotia in 1996, they passed on a wall clock, which had been given to my father-in-law by a patient and had hung on the wall in the main hallway of their home, to his son, my wife’s brother. It has been in storage ever since then.

I hadn’t seen the clock in nearly 30 years though I have vivid memories. In the 1980s and 1990s, my wife and I would bring the kids to visit their grandparents on weekends. The clock would resonate throughout the house. It was unforgettable, by its loud ticking and the four-hammer strike marking the hour and half-hour.

Made by Mauthe, it is a 1930s-style German box clock, dark in color, reminiscent of one in my own collection. In fact, except for minor details on the case, it’s almost identical to mine.

German "box" clock by Mauthe
German “box” clock by Mauthe, in my collection

My father-in-law loved the clock and had it for years, winding it without fail once a week. When it stopped, he would have someone local service it for him. He cherished it deeply, though I’m not entirely sure why. Perhaps, as a doctor, he valued it as a thank-you gift from one of his patients, or maybe he simply had a passion for clocks.

Sadly, my father-in-law passed away in 2012, and my mother-in-law passed away this year. While settling the estate, my wife and her brother started communicating on a deeper level, and the subject of the clock came up. Would I fix it?

Mauthe movement back plate
Not this clock but a similar Mauthe movement

The clock has now been passed to me for repair. I picked it up in mid-June, and my first impression was that the case was in excellent shape for its age. While the case has minor nicks and scratches that can be easily addressed, the dial is rough. Otherwise, the movement appears intact with no missing or damaged parts.

Overall, I believe the clock is definitely worth restoring. Once I evaluate the clock further I can determine what needs to be done, make any necessary repairs to the movement, and the case, test the movement, and return it to my wife’s brother. To have it displayed prominently on a wall and running again would be a testament to my father-in-law’s memory.

Although I have other projects on the go and cannot tackle this project until the fall, I am pretty excited about working on this clock. It is a perfect candidate for restoration but more importantly, it has great sentimental value.

In future posts, I will describe a step-by-step process of revitalizing the case and another on servicing the movement.

Kienzle time and strike movement servicing

I have just one other Kienzle clock in my collection and it is a rather unusual one, the World Time desk clock from the 1940s. I do not come across Kienzle clocks very often. They are no lessor quality than most German clocks, I just don’t see many around this region.

Kienzle World Time clock
Kienzle World Time clock

The latest is a German styled round top box clock. It was a an auction buy. I knew it was German at the time but did not know the maker. After a little research I discovered that it is made by Kienzle Uhren.

Kienzle Uhren GmbH is a well-respected German clock company that has a long history.

The company was founded in Schwenningen in southern Germany, in the Black Forest, by Johannes Schlenker, in 1822. In 1883, Jakob Kienzle became part of the family by marriage, and took control of the company, becoming its sole owner in 1897.

Jacob revolutionized production by mass-producing individual components and then assembling them. This modern manufacturing approach led to a massive expansion, and by 1939, Kienzle had over 3,500 employees and was making about 5 million wall-clocks and table clocks per year.

The company continued on through the years, changing hands a few times and gradually shifted production to wristwatches. It continues in business to this day as a watch maker.

The movement

In many respects it is a typical well-engineered German movement from the 1930s. The movement is compact in design and anyone who has worked on German movements will feel right at home. It has a 43 cm pendulum length and runs at 104 beats per minute as per the stamping on the back plate.

Kienzle movement, back showing pendulum leader and strike hammers
Front plate showing rack and snail mechanism

Unfortunately, the spring barrels cannot be removed separately, the movement must be completely taken apart to replace the mainsprings if they break.

The 4 hammer strike assembly can be taken apart separately. One advantage is that once the plates are back together the strike paddle can be easily positioned on the star wheel. The strike has a repeater function which is handy.

With top plate off and showing the placement of the wheels

All parts are hand-cleaned before putting them in the ultrasonic cleaner. Taking excess oil and grime off the movement prior to cleaning ensures a longer life for the cleaning solution. When the solution gets dirty enough I discard it.

The movement has a combination of leaf and lantern pinions, leaf pinions on the second wheels and lantern pinions up both trains. I expect the ultrasonic will do a great job cleaning the lantern pinions.

Taking the mainsprings out of their barrels

The mainsprings must be taken out to be cleaned and the barrels cleaned in the ultrasonic. The springs are quite powerful and mainspring troubles account for many problems with German clocks.

When the mainspring breaks movement damage can result. Teeth are torn form the barrel and the first leaf/lantern pinion is destroyed or the second arbor is bent. I have had movements go both ways from severe damage to simply a broken mainspring (which is easily replaced).

Cleaning of springs and barrels is therefore essential not only to ensure they are free from old oil and dirt but to inspect them for cracks, breaks, and tears. These mainsprings appear to be in very good condition.

Parts are sorted into containers

I typically preheat the Polychem Deox 007 solution and run parts for 20 to 30 minutes in the ultrasonic, switching off the heat midway through the cycle. I dry all the parts by hand and for the lantern pinions and some parts that seem to hide water, I use a hairdryer to ensure that everything is free of any potential rust build-up.

The mainsprings, which are cleaned of old oil are done separately in the ultrasonic cleaner.

All parts except mainsprings are placed in the ultrasonic cleaner

The next step is putting the re-oiled mainsprings back into their barrels and for that a spring winder is a must. Polishing the pivots come after that.

Olie Baker spring winder. Cleaning the strike side mainspring
Olie Baker spring winder. Cleaning the strike side mainspring

Bushing work

This movement might have been cleaned at one point in its life based on pivot scratches on the inside of the plates and worn screws on the back cock but it has never been bushed. When I tested the wheels in the movement I found the time side ran relatively freely while the strike side seemed stiff and sluggish. So, the movement is worn but the wear would be no more than typical for its age.

Following my first assessment I have determined that the movement requires as many as 10 bushings, 6 on the backplate and 4 on the front or, 5 on the strike side, and 5 on the time side. As expected there is more wear lower in the trains.

On the front plate are:

  • The second wheel time side, third and fourth wheel on the time side and the verge.

On the rear plate are:

  • Second wheel on the time side, second and third wheel on the strike side, third and fourth wheel on the strike side and the verge.

I always like to start with the most difficult, the pivot hole on the back cock which supports the suspension spring, crutch and pendulum.

In total 12 bushings were required, including the escape wheel. The escape wheel was pretty sloppy both front and back, and better to do those while the movement is apart. 12 is probably the most I have installed in a German clock in quite a long time.

Reassembly and testing

I generally perform a power test prior to the final assembly of the verge, rack and snail, and all outside pieces. It is a good check against my bushing work and if anything is tight or stiff I can address it without taking everything apart. Everything looked good at that point.

Both trains are moving and being tested before the other parts go on
Both trains are moving and being tested before the other parts go on

However, with verge installed, pendulum leader, crutch and pendulum, the movement consistently stopped after a few minutes. I took it apart and discovered that the 4th wheel on the time side was moving stiffly. As that wheel had a new bushing installed all it took was reaming out the pivot hole to free it up. Now the movement is running well.

Testing the Kienzle movement on a makeshift test stand
Testing the Kienzle movement on a makeshift test stand, beat amplifier is attached

Onward to the strike side and attaching the levers, snail and rack. The levers, rack and snail and gears are attached and finally the strike hammers are installed. The strike hammer posts must be bolted in from the inside of the back plate, something to remember when reassembling the movement.

When I got the clock only one strike hammer functioned but with all hammers repositioned all 4 strike hammers are doing their job and producing a melodic bim-bam strike.

The case does not require much attention other than a cleaning with soap and water.

There is absolutely nothing on the movement, gong block or case that tells me who the maker is though I now know it is definitely a Kienzle.

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