1 second Regulator – state of play

Discussion in 'Clock Construction' started by Phil Burman, Nov 30, 2016.

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  1. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    Just a short post to show the new bob/pendulum in brass, stainless steel and an invar 36 rod. This has replaced the previous prototype mild steel one and now includes temperature compensation via a stainless steel tube sitting on the regulation nut and supporting the bob at its’ mid-point. Also now included is a 5.5lb stainless steel drive weight.

    Phil:)

    new bob 1.jpg
     
  2. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    Cool
    Is it a calculated compensation or have you actually run it at a couple
    different temperatures to see how it is doing?
    Tinker Dwight
     
  3. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    #23 Phil Burman, Mar 7, 2017
    Last edited: Mar 7, 2017
    Both. I originally calculated the length and added 10mm to give me scope to home in based on observation. However due to my inexperience I didn't allow enough time for stabilisation consequently the compensator length appeared to be in error. Furthermore being a novice I also managed to confuse myself due to a coincidence that the room thermostat just happened to have a 1 hour cycle and that the clock had a inherent 1 hour rate variation due presumably to an anomaly with the 1 hour wheel. The upshot of this was that the thermostat variation matched the rate variation so I assume that the rate variation was due to this temperature variation. This gave me a calculated pendulum length of 5 meters in order to accommodate a calculated compensator length of 4 meters.:confused:

    So all of the above took me about a week but yesterday I finished a 24hr run with a maximum length compensator and tonight I am running a 24 hour test with the shortest compensator that fits with the length of thread available on the invar rod.

    Here's the plot from yesterday:

    blue is the pendulum amplitude -black is the rate - green is the room temperature

    PS: ingnore the values in the boxes at the top, I was using the gps module so they are not correct/relevant.
     

    Attached Files:

  4. Tinker Dwight

    Tinker Dwight Registered User

    Oct 11, 2010
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    A good start. I think I'd do some longer constant temperature runs first
    with about 12 hour soak.
    Then you can start looking at rate of change stuff.
    Tinker Dwight
     
  5. tok-tokkie

    tok-tokkie Registered User

    Nov 25, 2010
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    What do you conclude from those traces?
    The compensator is the maximum possible so the compensation is expected to be excessive?
    As the temperature dropped the period of the pendulum also dropped - which corresponds to over compensation?
    But then what happened? The period reduced in a spike then stabilised.
    In that last stable section the rate varied from 0.000 020 to 0.000 026 sec. So the range was 0.000 006sec. That is 0.5sec/day.
    I have a clock where the daily variation is worse than that. But I have no idea what is usual. What daily change in rate with the temperature being 'reasonably' stable (I don't mean US style temperature control) would you anticipate.
    I recognize that this is a path you are still discovering.
     
  6. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    I think you are right, the trouble is I get too impatient, although I seem to be so far off at the moment that I would like to see a result with under compensation, then at least I know where I am and that the correct compensation is somewhere in between the two.

    The current run with the shortest compensator (not yet finished) appears to also be over compensated, so my plan is to make a small clamp for the invar rod and put it directly under the centre support of the bob, i.e. zero compensation, then I will at least know if the ball is actually in the park.:clap:
     
  7. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    #27 Phil Burman, Mar 8, 2017
    Last edited: Mar 8, 2017
    Here's the plot for the shorter compensator. There seems to be a lot going on but one key point maybe that for the last part of the curve the rate recovers back to the starting point, which I think indicates less over compensation than the previous plot (or possibly zero). The somewhat massive initial drop in rate is surprising but I think it may be due to the pendulum being separately mounted on an alumimium backboard which is in intimate contact with the concrete wall, whereas the movement endplates are in free air, this will result in a differential expansion as the temperature changes. Also the backboard is bolted to the wall both top and bottom. If the bottom bolt predominates then as the temperature falls the pendulum will move down and the crutch will move up. This will change the degree of deflection of the upper suspension spring resulting in a change in input energy to the pendulum.

    Anyway I have now isolated the backboard from the wall with spaces and ensured that the backboard is firmly fixed to the wall by the top bolts, so that direction of movement of the board with temperature is matched by the end plates. We will see, it's running now.

    Phil:)

    PS: you have to remember that the recorded temperature is the instantaneous air temperature and may bear little relationship to the temperature of the various components of the clock.
     

    Attached Files:

  8. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    Here's the 16" dial with walnut frame. The dial needs some more work on the graining before silvering. There's a lot of separate steps in the engraving operation, one mistake and it's start all over again, as the reverse side of the dial can testify. I may redo it at some later stage but large lumps of brass can get expensive.

    16 inch dial 3.jpg

    Phil:)
     
  9. Allan Wolff

    Allan Wolff Super Moderator

    Mar 17, 2005
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    Phil,
    Excellent job on the dial; very intricate. I can't wait to see it when it is silvered.
    Allan
     
  10. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    Thanks Allan, at the moment I'm having trouble getting the right surface finish. The various engravings seem to affect how the wet and dry performs and it all looks a bit streaky. I did have to use a more course paper because of a number of scratches, maybe I just need to persevere with the 600 paper.

    Phil:)
     
  11. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
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    How are you graining it, vertically?

    I use 800 for graining, though usually I'm restoring and do a lot with 1200 to clean and leave the original graining with with some tarnish so that it doesn't look too bling on an old clock.

    Will be interesting to see your finished dial, I've never worked on a new one.
     
  12. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    I'm graining it circumferentially, pivoted about the centre hole. It's now clear that I should have taken more care regarding scratches on what was originally supposed to be the back side, and possibly I should have grained it before engraving, or maybe not. Everything I do related to clocks is new to me so most things end up being done at least twice. I just hope that what I learn I don't forget for the next one. I think maybe I need to start taking notes to compensate for my poor short term memory.

    Phil:)
     
  13. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
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  14. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    Thanks for the input, that's an interesting point. What's the technique for vertical graining, how do you control the process to ensure that the graining is straight and vertical.

    Phil:)

    PS: I think you may have identified the problem.:bigsmile:
     
  15. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
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    I have not done a round one yet but when I have had a dial centre to do I do it my hand.
     
  16. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    Yes but what do you do by hand, vertical or circumferential?

    Phil:)
     
  17. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
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    sorry, dial centres are grained vertically. They were silvered on late 18th century longcase clocks before they went to flat sheet dial plates that were all over silvered, those were grained vertically too. I haven't done one of those either. However I have done dial centres by hand.
     
  18. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    Hello again, sorry but I still do not understand. You say "dial centres are grained vertically". and "However I have done dial centres by hand".
    How do you do the centers by hand, vertical or circumferential?

    Phil:)
     
  19. novicetimekeeper

    novicetimekeeper Registered User

    Jul 26, 2015
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    Dial centres are grained vertically and I have done them by hand. IE Freehand
     
  20. Phil Burman

    Phil Burman Registered User

    Mar 8, 2014
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    OK I got there eventually. So you do it vertically but you control straightness and orientation by hand only.

    Phil:)
     
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