1880 Ansonia Iron Cased Clock - Rating and Accuracy

Discussion in 'Clock Repair' started by TimeAgainRoy, Mar 14, 2017.

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  1. TimeAgainRoy

    TimeAgainRoy Registered User

    Aug 23, 2011
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    I recently overhauled the movement and all was fine until I tried to rate it.
    Actually it is more of a trajectory than a rating.

    Essentially it gains 4 minutes over the first three days and looses 6 minutes over the remaining four days - so it is loosing two minutes a week.

    My question is - is this they way they behaved from new?
    There is no point in replacing the mainspring if they all behave like this!

    I have attached a graph produced by my excel spreadsheet logging the strike times over the course of a week
    [​IMG]

    Is it as good as it gets or do I have more work to do?

    Roy
     

    Attached Files:

  2. Willie X

    Willie X Registered User

    Feb 9, 2008
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    This is a common story on old clocks and IMO all short pendulum recoil movements were that way from the start. Similar dead beat designs are much more linear over a 7 day run. Some improvement can be made by using a heavier pendulum bob along with a lighter and longer mainspring. Improvement will be variable and probably marginal.
    Rather than spend a lot of time at changing things around, I think it's much better to just enjoy what you have and lower your expectations! ☺
    Willie X
     
  3. R. Croswell

    R. Croswell Registered User
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    I have to agree with Willie, but your error is perhaps a bit excessive. Make sure that the escapement is adjusted such that the drop off of each pallet is equal - that is, the escape wheel rotates the same number of degrees between each 'tick'. You also want the lift angles of the pallets to be equal. Note that between each tick the escape wheel backs up or 'recoils' a bit. This is normal but you want it to recoil the same amount between each tick. In other words make sure the escapement is a perfect as possible to minimize the isochronal error. It is often a mistake to just adjust the recoil escapement for maximum pendulum swing without regard to maintaining equal locks and drops.

    Other than that, if your clock gains 6 minutes by mid week, simply set it 3 minutes slow at the beginning of the week and you instantly have a 100% improvement in accuracy over the week.

    RC
     
  4. TimeAgainRoy

    TimeAgainRoy Registered User

    Aug 23, 2011
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    Thanks very much for your feedback.

    Essentially, although there is room for some improvement, in principal one is stuck with the trajectory!
    So I won't bust a gut to try and get a flat line!
    People always laugh when I say that you have to make friends with an old clock to really understand its little ways.

    I must say the the spreadsheet is very useful. In most cases two or three readings a day is enough, but in this case I went for broke to get the 168!

    All the best, Roy
     
  5. John P

    John P Registered User
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    Sep 17, 2010
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    I personally own 19 cast iron Ansonia clocks and 8 china clocks made by the same and none have such a timekeeping error.
    Ten of these are visible escapement which are the best timekeepers. I have been through the movements of each one and if one would show such an error after a month of run time, out it would come. I will not tolerate any more than 1 or 2 min per week. These clocks are capable of running almost perfect with the full week.
    I don't know what your clock needs but I suggest you take it back apart and inspect every part and make sure you don't have a bent pivot or arbor. Burnish the pivots and smooth broach the bushings and replace the springs. You can fit these a bit tighter in the time train and they seem to run better there.
    When they are right, 2 clicks will start the time train running.
    I'm sure you will find the problem, sometimes they don't rear their head till the 2nd time we look.

    J
     
  6. LaBounty

    LaBounty Registered User
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    Aug 29, 2002
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    This is called isochronal error and the curve can be shallowed by installing a thinner and longer mainspring. 3/4" x 0.0165" x 120" is a good replacement for a 3/4" x 0.018" x 96", if that's what your Ansonia movement is currently using.

    Good luck with it!
     
  7. R. Croswell

    R. Croswell Registered User
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    #7 R. Croswell, Mar 15, 2017
    Last edited: Mar 15, 2017
    One would expect the visible escapement movements to be better time keepers than the typical Ansonia with a recoil escapements. Either type should be able to be adjusted to end the week within a minute or so of the correct time if one has the patience. It is I believe the deviation from a straight line during the 7-day run that is the concern here. I agree that six minutes deviation from flat line is a bit excessive and should be able to be improved on, but 1 to 2 minutes deviation from flat line for a spring powered recoil movement with no Geneva stops and no temperature compensation is a pretty lofty goal that may be a challenge to achieve.

    RC

    Dave makes a good point. Conversely, if the original spring has been shortened after being broken, or replaced with a shorter spring that would exacerbate the problem.
     
  8. Willie X

    Willie X Registered User

    Feb 9, 2008
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    #8 Willie X, Mar 15, 2017
    Last edited: Mar 15, 2017
    Check the pallet faces closely for dents. Ruts are easy to see but a small dent can be missed. If the pallet is original and the faces are smooth and polished with the original pendulum, look to the springs.
    On rating this type of clock, I tell my customers that anything within + or - five minutes, after a week's run, is good. Trying for better is fine but if you can get the rate to land within this range you are pushing the capability of the clock.
    Question, what kind of clock do you have? Ansonia made regular size cast iron mantel clocks with their standard size movements; they also made smaller versions with a smaller movement, both were 8-Day movements but the smaller movement is more like a novelty movement, not as capable as the larger movement.
    Willie X
     
  9. shutterbug

    shutterbug Moderator
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    I've also worked on Ansonia's with narrow springs like the one day clocks used, but they were 8 day runners.
     
  10. John P

    John P Registered User
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    Some folks like chevy's or fords, I like Ansonia and really enjoy repairing these and collecting parts to complete all Ansonia clocks I can. They were different grades produced and some are quite fancy.
    [​IMG]
    Here's my Ansonia parts collection
    [​IMG]
    [​IMG]
     

    Attached Files:

  11. TimeAgainRoy

    TimeAgainRoy Registered User

    Aug 23, 2011
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    It is great that there is so much knowledge out there.

    I refaced the pallets, and they needed it!, so I suspect the mainspring.
    David's recommendation to use a 3/4" x 0.0165" x 120" is a good one.

    I have another similar movement to do, so I will do that first, see how it goes, then come back to this one.
    I have a bit of work to do - but nothing like John Ps workload.
    Many thanks
    Roy
     
  12. R. Croswell

    R. Croswell Registered User
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    Refacing deeply rutted pallet faces, especially the exit face on a recoil strip pallet set, usually increases the opening between the pallets. Closing the pallets to compensate then changes the lift angle. Perhaps small issues but it all adds up especially if the pallets have been reground before. So in a clock that's already experiencing isochronism issues it may be worth carefully the final geometry of the escapement.

    RC
     
  13. TimeAgainRoy

    TimeAgainRoy Registered User

    Aug 23, 2011
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    Sound advice, RC. But presumable is it a matter of trail and error, observation, patience and persistence to sort out.

    One thing that amuses me - no one has asked how the heck I produced the data for the graph!
    Certainly not by sitting in front of it for a week, that's for sure!

    Roy
     
  14. harold bain

    harold bain Forums Administrator
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    Roy, it just sounds like more work than most of us would want to put into the quest for accuracy on what was not sold as being a quality regulator type clock.
     
  15. R. Croswell

    R. Croswell Registered User
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    OK, how did you do it?

    RC
     
  16. shutterbug

    shutterbug Moderator
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    I thought it was pretty clear:
     
  17. R. Croswell

    R. Croswell Registered User
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    Yeah, that's how I have done it but it sounded like the OP had devised some automatic way to gather the data to enter in the spread sheet so he didn't have to sit there all day and record it. I believe one can do this with the Microset with the accessory computer interface module (which I don't have). Always open to a new technique.

    RC
     
  18. shutterbug

    shutterbug Moderator
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    I have the Microset, but not with that feature. I suspect you are correct though ;)
     
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