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Hermle 340-020

Superpot

Registered User
Jul 6, 2009
68
1
8
Hi everyone, I am in a bit of a dilemma. I have a mantle clock (1975) in for repair. The original floating balance was broken and I ordered a new replacement one but its not the floating balance type any longer as it was replaced with a more modern version but I was told it was a direct replacement. Ok now for the problem. On full wind the clock gains so much time and runs a couple of hours ahead of time so I did some research and all the advice is to add weight to the balance wheel to slow it down which I did. At the point I managed to get it to run 5 mins slow per hour I thought I was onto a winner but.............. as I kept adjusting via weight very carefully it was almost corrected but when I put the clock back to a full wind it's racing away again at a very fast rate of knots!Can anyone shed nay light on this to me very strange situation? It is really baffling me I have to say and I'm ready to concede on it. Any help greatly appreciated as always.
 

Dick Feldman

Registered User
Sep 1, 2000
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Colorado, usa
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It is common practice for clock repair people to zero in on balances and springs for a solution. If your balance was broken, it may have been the second thing wrong with the movement and not the primary problem. If the clock came from the factory with a floating balance, it was manufactured some 40 years ago because that is about the time manufacturers stopped using those. The normal life span on a Hermle wheel train is about 20-25 years. (I assume the movement is a Hermle). After that time, the train will experience low power due to friction due to wear. You should be able to tell the manufacture date from the date code stamped on the rear plate of the movement plate. If you have not addressed wear in that movement, you are likely fighting a loosing battle.
Balance movements are prone to be erratic when not supplied enough power. They will run slow due to low power and also will sometimes "short cycle" (run fast) with low power. The original balance was probably the victim of a previous repair attempt. Balances will normally not fail unless someone has messed with them. My guess is the movement wheel train is lacking power and until you solve that, the clock cannot keep time reliably.
That is what I think,
Dick
 

dickstorer

Registered User
Oct 19, 2010
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Hampton, Georgia
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I think as does Mr. Feldman. A video of the balance wheel in motion would be most helpful. It would show how much rotation the wheel is getting.
 

Superpot

Registered User
Jul 6, 2009
68
1
8
Thank you gentlemen. It is indeed a hermle 340-020 movement and after speaking to the owners they are going for a brand new replacement movement. Lets see where I can get the best deal on one from. I am on mainland Spain.
 

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