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help keeping time

Dman

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I have two mantle clocks, one an american time and strike movement and the other one a french movement. I have been working on them for quite a while trying to get them to keep time. i get close over the course of the week, then I wind them and it seems like i'm back to square one. it fluctuates between too fast and too slow. Is there anything I can do to make it more consistent? the customer is very insistent that it keep good time.
 

bruce linde

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i'm confused... you say you have two clocks, but then say "it" fluctuates between too fast and too slow.

american strike and french clocks are very different... what have you done with them? have you serviced them both down to sanding/smoothing/cleaning the mainsprings, polished pivots, did bushings, checked depthing, etc?

assume from 'the customer wants...' that you're a clock repair shop... but don't know...

what i would do is start with more info... wind and reset time, and then keep a +/- log every day for two weeks/cycles... it would be interesting to compare the two sets of results. btw, my clock mentor does this for his 1840 austrian astronomical regulator but also logs daily temps and barometric pressure... very informative.
 

Dman

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sorry, should have said "they" fluctuate.
both clocks have been cleaned, pivots polished, and had bushings installed.
I run a small repair shop out of my home. graduated from Gem City College about 3 years ago, so I am still learning, but possess enough skill to do most work.
 

bruce linde

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got it... but did you do the mainsprings? i mentioned in another thread that i had serviced a mainspring (in a chelsea) and ended up sending to david labounty for another issue. when i called to inquire about progress he basically sniffed at my mainspring servicing and told me he did it right. :)

'right' apparently included sanding them smooth to get off any old residue and then standard servicing.... who knew?!? :)
 
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Dman

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well if that’s the case, I did not. I will try that. As I said, still learning
 

Willie X

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FYI, no mechanical clock will "keep time". The rate is constantly fluctuating, much more so for spring driven clocks than weight driven clocks.

Your clocks should be wound and set to time. 7 days later, check them and wind them again. Make adjustments as you think necessary but only once every 7 days. This is how you fine regulate any clock. A high grade clock will be fairly stable through the 7 day cycle. In other words the rate won't wander around to much. A lower grade clock will vary all over the place, usually gaining time during the first few days of the wind and loosing time later in the week. That's just the way it is.

If you are doing all that can be done, short of redesigning the clock, you will have to accept the fact, that's the best it will do.

One rule in clock repair trade is to never oversell the timekeeping ability of any clock. "It used to keep perfect time" is something customers like to say but this is also a false statement and probably should be clarified before you take in their clock.

Willie X
 
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JimmyOz

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To back up Willies assessment,

I finished a very nice open escapement French movement a few months ago, got it close to good time keeping over the week in the test stand, then put it in the case. I gave it a full wind and was going to fine adjust it after 7days, however I missed the 7 day mark so I thought just leave it till it stops, well it just kept going and going, 21 days later it stopped. I checked the strike and that still had power to operate. I then set the clock to my computer time, it gained 2 minutes over the week then started to lose those 2 minutes over the 2nd week and lost about 2 minutes over the 3rd week. I was amazed that it lasted 3 weeks, I redid the full wind to check I was not having a senior moment and it did the same again.

The pendulum overall length is 8 1/2 inches and 6 5/8 inches from hook to centre of the bob which is 2 1/8 inches in diameter and quite heavy, the movement, pendulum and bezel have the same number so all original.

Options are, wind it every week and tune it to that or leave it with a 4 minute difference over 3 weeks, I don't like shortening the time the clock should run, in my view it was designed to run for the 3 weeks, anyway I only have 2 clocks running and this is just another that will sit with all the other clocks I don't wind (I never leave a clock wound that is not in use).

Back to the point, even well made quality movements vary, although this is a surprise it ran so long.
 

bruce linde

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to back up jimmyOz's asessment... and expand on my earlier comment....

if you keep a daily log, you might find that it runs more consistently between day 3 and day 10.... at which point you could then wind it fully, let it run for two days, and consider day 3 your starting point... and then wind it every seven days from there on out.
 

Willie X

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I always liked a 7 day winding schedule. It's difficult to do anything else for me.

I do have one GF clock that won't quite make through the 7th day. So, it gets special treatment, with a fresh wind whenever the weights get down to the bottom of the glass, about every 5 days.

I have never seen a good explanation of the French run time thing. I just tell everyone to wind them every week and only use two fingers. :)

Willie X
 

JimmyOz

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It seems the French work in extreems, the clock movement that goes for 21 days then the Comtoise movement that you need to be 8 foot tall to wind it and get 7 days out of it before the weights hit the floor. :?|:screwball:
 

Keith Doster

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got it... but did you do the mainsprings? i mentioned in another thread that i had serviced a mainspring (in a chelsea) and ended up sending to david labounty for another issue. when i called to inquire about progress he basically sniffed at my mainspring servicing and told me he did it right. :)

'right' apparently included sanding them smooth to get off any old residue and then standard servicing.... who knew?!? :)
I'm curious about your reference to "sanding them smooth". When I clean mainsprings, I use 0000 steel wool and WD-40. Then I use lacquer thinner to remove the WD-40. Does LaBounty actually use some sort of sandpaper?
 

Willie X

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I have been using sandpaper and recommending sandpaper for many years. If the springs are very dirty with a lot of buildup, your wasting your time with steel wool. Start with 150grit sandpaper and go to/through a couple of finer grades. Be sure to stay with the 150 until all the real work is done. You aren't trying to remove metal, just the crud and some of the roughness. The intermediate finer grades don't take much time. Finish with 2-0 and finally 4-0 steel wool.

It all depends on the condition of the spring. On a clean and smooth spring 4-0 steel wool alone will be fine. But in this case little or no difference will be made in the function of the spring. iOWs, it only needed lube ...

For the last couple of years, I've been using mineral oii (same as 'Baby Oil') for cleaning springs. It's cheap and easier on your hands than 10-W machine oil, or WD-40, but all of these are good for the cleaning process.

Willie X
 
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shutterbug

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Another idea that has not yet been addressed is the Geneva stop principle. The stops were designed to prevent winding the mainspring too tight. If you wind the clock and count the turns, then wind it the next week with a full turn less, the fast end of your issue might be diminished, and the clock would still run the full 7 days. If one turn less lasts the full week, try two. The idea is to confine the spring strength to the center of it's power curve.
 

Dick Feldman

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You should remember when and where those clock movements came from.
The American time/strike was probably produced a hundred years ago or so. During that time, clocks were sold off the back of horse drawn wagons along with pots and pans, patent medicines, thread and flour. The head of the household would take trips to town to replenish supplies (and pick up mail that would came via the Railroad Postal Service) on occasion and stop at the Western Union Station to set his watch. He would then go home and set the house clock from his watch. That was accurate enough for a society that got up in the morning when the cows complained and wanted to be fed. Those clocks were made for times when electricity was a rare home option. (Along with indoor plumbing, central heating, insulation, etc.). Technology has advanced since those times. We have a tendency to apply today’s standards to old clocks. Time standardization in the USA was originated to help make railroads efficient. The operation of the Western Union telegraph synchronization is a wonder in itself. That system was used well into the 1960’s and 1970’s. That is not really that long ago.
For a learning experience, put a meter on one or both of those clocks that measures BPH. The BPH translates directly to how fast the hands are moving, which seems to involve your initial question. When the movement approaches the cam for the strike mechanism, you will see a slow down of BPH on the time train. As the lever falls off of the cam, the BPH rate will again pick up. The actual rate of the moving hands is not constant in any one hour. The time keeping ability of the clock is actually an average of fast and slow operation. Add a little wear and wobble in the time train and there will be more inefficiencies.
No matter how anyone hopes, those mechanical clocks cannot keep pace with the vibration of a quartz crystal or of an atomic clock.
That is what I think,
Dick
 
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Willie X

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When you're speaking to a customer. A light sprinkling of Dfs history lessons can go a long way toward a general understanding of the clock's capabilities, or lack of capabilities. The owner needs to have some realistic expetions about their clock. Is what I think, Willie X
 

Dman

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Thank you everyone for chiming in. I sanded and cleaned the mainsprings better, and so far they are keeping time about as well as I expect mantle clocks to. I do realize that clocks don’t keep perfect time, but as I lack the experience of many on this forum, just wanted to be sure I had done all I could. Will definitely keep that history lesson in the back of my mind for explaining to customers.
 

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