How old is and how do I slow down my Hermle 340-020 Mantel clock?

Embemor

Registered User
Feb 16, 2016
9
0
0
Country
Hello,
I am new to this list as my wife and I have recently inherited my father-in-laws clock repair hobby/business tools and clock bits and pieces. This looks like a tremendously helpful group for what I see as a fascinating hobby for me.

I have been working on a Hermle mantel clock for a friend. The movement looks very much like a 340-020, but it has no numbers or identifying marks aside from the Franz Hermle logo. I'm thinking it was made around 1940, or so based upon somewhat similar clocks that I have seen advertised on e-bay. Is there a way to determine what year this clock was made?

Also, the clock is running too fast and I can't slow it down sufficiently with the balance wheel weight adjustment. There are two weights on the wheel. What could cause the clock to run faster than the range of its regulation mechanism? (I can understand a clock running slowly because of an accumulation of dirt etc, but a clock that runs too fast?? What could cause that??) Any ideas how I could slow this clock down?

Thanks for any help or suggestions.
 

harold bain

NAWCC Member
Deceased
Nov 4, 2002
40,853
179
63
73
Whitby, Ontario, Canada
Country
Region
Welcome to the message board, Embemor.
If your clock has a floating balance, it will date to after the mid 1950's, and if there is no date code, before 1962, which is the earliest Hermle I have seen with a date code. Clean the clock movement first (a strip-down cleaning), then see how the timekeeping is. Running fast is usually associated with lack of power due to a dirty movement.
 

Dick Feldman

Registered User
Sep 1, 2000
2,613
225
63
Colorado, usa
Country
Region
Where are the pictures of your clock? Can you supply some?

I agree with Harold, but----Lack of power can also come from wear or other factors.
Clock movements, like all machines will wear with time.
The "normal" lifespan of a Hermle clock movement is 20-30 years, sometimes less.
All of the cleaning, oiling and adjusting will not solve wear problems.
How much does the balance wheel rotate in degrees?
Are the leaves of the balance spring touching each other?
Are they plugged up with oil?
Has someone sprayed the clock with WD-40?

Just because the clock runs, does not mean it is healthy and can give reliable service.
There are many books available at your local library that will answer basic clock repair questions.

Best Regards,

Dick Feldman
 

shutterbug

Moderator
Staff member
NAWCC Member
Oct 19, 2005
46,961
1,996
113
North Carolina
Country
Region
Just for a bit of explanation, a dirty movement reduces the amount of swing on the balance wheel. A reduced swing translates to a faster oscillation, and speeds up the clock. There is rarely enough adjustment available to compensate.
 

Embemor

Registered User
Feb 16, 2016
9
0
0
Country
Thank you for your replies. I will try a strip-down cleaning. I have noticed that the balance wheel is not exactly perpendicular to its 'axle' (forgive me for likely not using the correct term there), but it does seem to rotate freely. It rotates about 100 degrees each direction, which from what I've read on this forum is considerably less than it should.
Thanks again for your help. I'll report back as things progress.
 

MARK A. BUTTERWORTH

NAWCC Life Member
NAWCC Member
Jul 4, 2009
2,488
156
63
Muscatine, Iowa 52761
Country
Region
Just for a bit of explanation, a dirty movement reduces the amount of swing on the balance wheel. A reduced swing translates to a faster oscillation, and speeds up the clock. There is rarely enough adjustment available to compensate.
Right. Adjusting the balance is almost never needed. Your problem is not enough power getting to the balance
 

harold bain

NAWCC Member
Deceased
Nov 4, 2002
40,853
179
63
73
Whitby, Ontario, Canada
Country
Region
Do a message board search on floating balance clocks. They should not be cleaned the same as the rest of the clock, and also should not be oiled after cleaning them.
 

Willie X

Registered User
Feb 9, 2008
14,351
1,599
113
If your clock has a small bridge on the back plate containing the escape wheel and a couple of other wheels with short arbors, it is a good movement worthy of a full repair. This older movement is completely different from the trouble prone movements that started about 1968-70. Unfortunately no parts are available for these older movements. You can get parts for the post 68-70 movements but it is far better, and less expensive in the long run, to simply replace them.
Willie X
 

Tinker Dwight

Registered User
Oct 11, 2010
13,666
77
0
Calif. USA
There are two basic types of escapements. There is the recoil
and the deadbeat.
In the recoil, the escapement constantly pushes against the timing
element, except for the instant of the drop. It both pushes it faster
as it swings across the center and then pushes against the swing to
cause the natural swing to be shorted for part of the cycle. This
causes the timing element to run faster than its natural speed. How
much faster depends on a number of variables. This is why the basic
deadbeat was invented. It only pushes on the timing element as
it crosses the center and then goes into a locked state, allowing the
timing element to move at its natural speed.
A balance wheel uses a form of deadbeat where the lever only pushes
at the center of the swing. For the rest of the cycle, it is clear of the
balance wheel and it then runs at its natural speed.
The problem happens that when the power is reduced, the lever fails
to lock out of the way of the roller on the balance wheel ( called banking )
and it then runs like the recoil escapement, where the force of the
drive speeds up the natural timing.
If the swing is good, this recoil like action does not happen but as the
power to the escapement is reduced, it begins to fail to bank ( or lock
clear of the balance wheel ) causing significant speeding of the clock.
I hope this makes some sense.
Tinker Dwight
 

Embemor

Registered User
Feb 16, 2016
9
0
0
Country
My God! This is complicated stuff! I seem to have unearthed a world that I never before knew existed! Fascinating!
At the risk of appearing like the complete village idiot, could I not simply add a little weight to the balance wheel to make it rotate more slowly.
I was up all last night and cleaned the floating balance and escapement in naptha. I also removed the barrel spring and cleaned it and reloaded it. The balance wheel now rotates about 200 degrees whereas before it was only rotating about 90-100 degrees. (slow motion video with an iPhone was a great tool in figuring that out!!)
It seems a shame to just give up and replace the movement - after all, when does a family clock cease to be the family clock?
Thanks for all your input - I am really enjoying this!!
Dave C
Nanoose Bay, British Columbia,
Canada
 

harold bain

NAWCC Member
Deceased
Nov 4, 2002
40,853
179
63
73
Whitby, Ontario, Canada
Country
Region
Have you figured out how to regulate the balance by moving the spider part on top of the wheel? It may be in range of regulation with its extra amplitude.
Did you also oil the movement and the mainsprings? Good start, Dave.
 

Piisimuhkaan

Registered User
Sep 1, 2015
77
1
0
Ottawa
Country
Region
How is your clock running?

I recently repaired one of these movements and really enjoyed it. They run well and keep good time.

I have noticed that the balance wheel is not exactly perpendicular to its 'axle' (forgive me for likely not using the correct term there), but it does seem to rotate freely.
It sounds like the balance wire has a bend in it. The wire can easily be bent when the speed of the balance is adjusted.
 

Embemor

Registered User
Feb 16, 2016
9
0
0
Country
Hello again,

The clock is running about 15 seconds fast per day even though it is set to its slowest setting. After having cleaned the balance wheel mechanism it slowed considerably, but still not enough to be fully within the limits of the regulating setting. I guessI'll probably have to settle with it as is, or perhaps find a new balance wheel assembly. (the one that is in the clock was bent a little for some reason) In any event here are some photos and a slo-mo video.

Does it still look as though it was made between mid 1950s and 1962 as per Harold's post, above?

Thanks,
Dave

340-020 Movement.jpg Clock 1.jpg Sandy's clock.jpg [video]https://youtu.be/aCKlaXd3uMQ[/video]
 

shutterbug

Moderator
Staff member
NAWCC Member
Oct 19, 2005
46,961
1,996
113
North Carolina
Country
Region
Your pictures are too small to see anything, Dave. Can you do a larger megapixel setting?
 

harold bain

NAWCC Member
Deceased
Nov 4, 2002
40,853
179
63
73
Whitby, Ontario, Canada
Country
Region
Let us know how the timekeeping is over a full week. Hard to measure 15 seconds without having a second hand to watch.
 

Embemor

Registered User
Feb 16, 2016
9
0
0
Country
Thank you everyone for your help. I ordered a new floating balance wheel wire and replaced it. I cleaned the movement as best I could without doing a complete teardown - I was too timid for a teardown! After doing that, I found that the balance wheel was rotating about 300 degrees and I was able to regulate the clock to be too fast or too slow. I managed after a few weeks to regulate it so that it was only gaining about 2 minutes a week. I'm not sure whether that is within the limits of acceptability to the purist. My friend, who owns the clock, was delighted to have it back again, running and sounding the familiar Westminster chimes that reminded her of days long ago when she was comforted by the same clock as it softly chimed in her grandmother's house.
Cheers and thanks again,
Dave
 

Forum statistics

Threads
167,147
Messages
1,456,506
Members
87,334
Latest member
fredericdb
Encyclopedia Pages
1,057
Total wiki contributions
2,914
Last edit
E. Howard & Co. by Clint Geller