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Clocks, Watches/broken hour chime spring replacement


QUESTION: I have a Hermle 340-020A movement in a mantle clock and the spring for the hour chime recently broke while I was winding it.
Is this something I can repair?
Are parts available for it, where?
If parts are available, do you know where can I purchase them?
Thank you.

ANSWER: Gregory, a couple of things here.  I think you are talking about the strike mainspring which is on the left side of the movement when looking at it from the front.  When a mainspring lets loose, It can be because it broke, one of the ends let go or the ratchet click or click spring failed.  When this happens, the barrel can be damaged, the click spring can be weakened or the next arbor (shaft) can be bent.  Any of these things have to be fixed if so damaged.  Before replacing parts, these items must be diagnosed by someone that can detect the damage.  If the only problem is a broken mainspring, it can be replaced, but if the barrel is damaged, the complete mainspring/barrel assembly has to be replaced.  If it is only the mainspring, a special bench tool called a mainspring winder is used, or it has to be done by hand.  This takes a lot of practice to wrap the mainspring into the barrel.  If done incorrectly, the mainspring can let loose in the process and possibly cause some personal injury.  The mainspring barrel has a cap on it that is relatively easy to remove, but getting it back on can be rather tedious.  I have used a vice or clamp to do this, but have a special compression tool I use.

The parts are available for your model clock which is manufactured by Hermle. However, I have made it a policy not to instruct inexperienced persons on working with mainsprings because of the potential injuries.

Since the question concerns available parts and where to obtain them, you can contact any clock parts supplier such as Timesavers, Merritts, R&M Imports, Ronell, Mile High, Black Forest Imports, etc.  Google any of these and most have On-line catalogs.  You would be looking for a strike mainspring, or mainspring barrel assembly for a Hermle 340-020 movement.

If you feel you don't want to tackle this job, it would be best to take it to an experienced clockmaker and have them service your movement.  If you don't know of one, contact me at my shop email address below and let me know the area in which you live, I'll see if there are any members of my Internet Clocksmiths group near you.

Good luck,

John Newman
The Village Clocksmith
Vintage Emperor Clock Consultant
Located in 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.  

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

QUESTION: Thank you for the thorough answer. This doesn't sound like something I can easily do, so if you know of any clock repair stores in the Kalamazoo Michigan area, I'd appreciate their contact info.

Gregory, I do have a friend and fellow clockmaker in Rockford, which is about an hour north of you.  We attended a clockmaking seminar together quite a few years ago and I haven't been in touch with him in some while.  But I have contacted him and will let you know if he is taking in work now.  Incidently, I attended a Howard Miller clock seminar in Zeeland a while back and while I was in there I visited another friend for a few days in Wayland.  He was an independent clock supplier and has since passed away.

If you will reply to my shop email address I had given you, I will let you know when I hear from the Rockford clockmaker.  This helps free up the Allexperts question queue, of which I have a limited number per day.  Thank you.

John Newman  

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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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