Clocks, Watches/Hermle 340-020


QUESTION: I am the owner of a Hermle Mantle Clock 340-020 movement with a floating balance. I just recently have it service. The problem I experienced is that the clock is running for a few hours and then just stops. I called the service provider but he said that the clock was running well when I accept it from him. Now my hands are in my hair. From one of your answers to a previous question you that “First of all; the movement must be running well or it will not keep time. The disc on the balance should make close to one complete revolution when the clock is running. If you get 75% or less that a full turn your problem may be that the clock is not running well.” If I look at the balance wheel, it turns about half a revolution. Can this be the problem?
Thanks in advance.

ANSWER: Floris, I am sorry to hear about your clock.  I see two issues here.  First, The balance wheel is the regulating device for timekeeping and it should run reliably.  Failures can be attributed to either friction in the floating balance itself or the escape mechanism out of adjustment.  The relationship between the pins on the balance wheel/fork/escape wheel.  Also there can be that there is not enough power getting to it.  This would be a result of friction in the drive train (gears from the mainspring to the hands and floating balance) or a weak mainspring.  

The second issue is that of the repair service.  In the clock business, as well as any other, products and service should have some type of warranty unless otherwise specified. As is the nature of the area in which I live, I have a policy that I do not offer a "limiting" warranty on any of my work.  By that, I mean that if at any time something goes wrong with the clock, I will work with the customer to determine what caused the problem.  If it is something for which I was responsible, or a minor adjustment or fix, I will take care of it.  If it is a result of future worn parts or outside damage, I will discuss a charge.  So far, I have not had any complaints on any additional work for which I had to charge.  Also the little "freebies"  I had to charge.  Others nearby will offer a warranty with a certain time limit.  I do offer the factory warranties on items such as complete movements or clocks.

I do know that when a clock is transported and set up by the customer, a clock can get out of adjustment from rough handling, and especially pendulum regulated clocks that can get out of beat. However, the floating balance clocks are not affected the same as balance types.  Again, I do not know how business is handled in your area, but I would think that there should be something more than " was running well when you accepted it..".  A proper clock repair should last for years.  This reminds me of a story when back in the 1950's I was a teenager and interested in cars.  There was a used car dealer that included in his inventory some cars that would barely run, or what we called junkers.  He had some good old down home humor and on these cars he would offer one of two warranties. One was that he guaranteed it until it left the lot, and the other was that if it broke in two you could keep both halves!

Not to make light of your situation, but I would think that if you paid a "fair market price" for the repair work, it should run reliably for some time.

John Newman
Old Prattvillage
Prattville, Alabama

---------- FOLLOW-UP ----------

QUESTION: After reading your answer I find that if the wheel stops and I start it by hand, it seems if the balance wheel loose momentum after a while. Then at last it stops.

All of the mainsprings are wound up, aren't they?  If the floating balance wheel is loosing momentum with no jerky or erratic motion, it is not getting enough power to maintain the oscillations.  As I mentioned before, this could be a result of friction in the time train or a weak mainspring.  The time mainspring (the middle winding hole in the dial) should maintain sufficient power to run the clock on a couple of winds as well as a full wind.  If you any erratic motion w while before it stops, it can be an adjustment or a part that is not in alignment.  I don't know anything you can really try.  If you would like to get back to me for further discussion that will be fine.  If you don't mind would you reply to my shop email address below as I have a limited number of of Allexperts questions per day.  Thanks.

John Newman
Old Prattvillage
Prattville, Alabama

Note concerning questions not related to Allexperts:  Because of my commitment to answering Allexperts questions within a prescribed time limit and the large backlog of clock work at my shop, I regret that I cannot answer personal email questions on a timely basis, other than Allexperts follow up questions.  I will try to answer these emails as soon as I can. Thank you for your patience.  

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John Newman


As I am not a certified appraiser I do not give values of clocks over the Internet. There is very little published information on what I consider to be the value of "modern production clocks". However, considerations are what the clock originally sold for, the condition of the case and movement, and particularly the area in which you live, the demand and the economy. ALSO, WATCHES ARE NOT MY FIELD. However, I can advise the clock owner on proper maintenance of a clock to keep it running, small corrections and adjustments and how to move a clock without damaging it. I can also advise on obtaining parts for clocks. As clock case model label numbers are difficult to relate to the movements, it is helpful if you can give me the information usually found on the movements themselves. Modern clock movements usually have the information on the back plate of the movement. I have been a clockmaker for about 40 years and was plant engineer in the mid 90's and later operations and engineering consultant at Emperor Clock Company in Fairhope, Alabama. I now have my own clock shop in Prattville, Alabama.


One of my greatest accomplishments was traveling to China to assist a clock factory in building clocks to the standards which we required at Emperor. With the proper specifications and quality control, some beautiful clock cases were built. The factory people from the wood carvers to the plant manager were very congenial, friendly and I left a lot of wonderful friends when I returned from my trips.

NAWCC (National Association of Watch and Clock Collectors) 30 years Prattville, Alabama Chamber of Commerce

Horological Times, a publication of the American Watch and Clockmakers Instute. Collaberated column author, with Photos and ideas for clock movement conversion article.

Associate of Science Mechanical Engineering Technology Emperor Introductory Clock Repair (Eventually taught a portion of the class after becoming employee)

Awards and Honors
Small Business of the Quarter (Prattville, Alabama) Leadership Class of 2009 (Autauga County, Alabama)

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