Grivolas keeps stopping

Discussion in '400-Day & Atmos' started by Dells, Mar 15, 2020.

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  1. Dells

    Dells Registered User
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    Oct 18, 2019
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    Hi all
    I am hoping someone can give me some suggestions as to why my Grivolas torsion clock keeps stopping?
    The movement is the Gravolas own and there seems to be no common hand position or length of time, sometimes it will run for a couple of days or a couple of weeks, all I have to do to set it going again is Re set the time and start the disc pendulum again then it will work fine again and it keeps good time.
    When I purchased it I could not find the correct torsion spring so it has a thinned down 0.045 but after setting the beat and a few times fine tuning it runs fine until it will stop all of a sudden and I can’t find any reason for it.
    If anyone has any suggestions it would be mush appreciated.
    Thanks in advance Dell
     
  2. KurtinSA

    KurtinSA Registered User
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    I don't have specific experience with the Grivolas to know if there a special aspect of the movement that needs attention. I have run across several clocks that work as you suggest...runs for a while, sometimes short durations, sometimes longer. I have begun to notice that some of these clocks - older clocks, clocks with thin plates - probably could stand to have a few bushings replaced. If the pivot holes wear enough, it will change the depthing that the wheels and pinions have.

    Kurt
     
  3. Dells

    Dells Registered User
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    Thanks Kurt
    I hadn’t thought of that because wear is minimal on torsion clocks but it’s worth a look, I was thinking of striping and cleaning the movement anyway as I haven’t done it yet, just replaced the torsion spring.
    Dell
     
  4. John Hubby

    John Hubby Senior Administrator Emeritus
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    Dell, how did you thin the suspension spring?? If you thinned only between the fork and bottom block that is likely your problem, because the section between the fork and bottom block is now too thin and the section between the fork and upper block much too thick. That small section between the fork and upper block actually is much more important than the long lower section, especially when you are having to remove about 0.0004 inches to get the equivalent performance of the correct spring (0.0040 in.). No question you will get erratic performance with the spring so much out of balance.

    The best thinning procedure is to remove both the fork and upper block, hold the bottom block and stroke the entire length of the spring from bottom to top. You can test by just installing the top block, hanging from a stand or the upper suspension bracket of the clock, hang the pendulum and give it about a 3/4 turn and let go. It will rotate plenty long to measure the rate; you want to have it just a bit fast, e.g. 59 to 59.5 seconds to make 8 beats.
     
  5. Dells

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    Hi John
    That is exactly how I thinned it holding bottom block, it keeps good time when it is running and it will run for days or weeks and when it stops it’s not at a certain time, all I do is set time again and start the pendulum and it runs again for days or a few weeks.
    Very frustrating Dell
     
  6. Dells

    Dells Registered User
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    Finally got fed up with clock keep stopping randomly, as I haven’t done anything with it apart from fitting a new torsion spring, I thought I would strip and clean it , well I think I may have found out why it stops randomly, everything is covered in oil, the centre pinion has bits of dust and hair stuck to it as do most other parts.
    20BF685F-55C4-4130-AF2F-685AC9AD50ED.jpeg
    so hopefully after a good degrease clean all should be good,
    Dell
     
  7. tracerjack

    tracerjack Registered User
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    Nine times out of ten, just cleaning and servicing the mainspring gets the clocks I work on running. Every once in a while, the cause is damage, but for me, it has not been very often.
     
  8. John Hubby

    John Hubby Senior Administrator Emeritus
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    I always do a complete clean and lube even if the clock “looks” good. Well with the time.
     
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  9. Dells

    Dells Registered User
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    I already had a couple of other clocks in line for servicing that’s why I didn’t do it straight away but as my signature still learning, but why do some clocks repair people think just covering everything in oil is good for the clock, anyway it’s going to get a good clean today and I must say everything to do with the clock is good quality, this is the first Gravolas I have worked on.
    When I took the case apart there was I thought a screw missing on one of the brass corner posts but it had been sheared off, any suggestions as to how to remove the stub ( there is mot very much stuck out)
    Any suggestions would be appreciated Dell
     
  10. Les Sanders

    Les Sanders Registered User
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    Every one has a process this is mine for 400 Day Clocks, I remove the hands and dial. 2. I leave the movement assembled and do a 1/2 hour ultrasonic cleaning. 2. rinse, dry and disassemble. 3. I check each arbor for play in its hole. 4. I reclean the plates, I then peg each hole with a sharpened pith wood piece dipping it in solvent to remove crud. 5. I now reclean all of the parts, I polish each pivot. Clean, inspect the mainspring lube it 6. I check the suspension against the Horolovar book 7. If the suspension has any problems I make a new one. 8. Ready to put is all back together and test being prepared to adjust whatever the movement needs. Each small problem avoided as you go through the process compounds and compounds some more. This just my 2 cents.
     
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  11. Les Sanders

    Les Sanders Registered User
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    sometimes you can drill the broken part and use a easy out.
     
  12. Dells

    Dells Registered User
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    Do they make easyouts that small ?
     
  13. KurtinSA

    KurtinSA Registered User
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    Do you have a picture of the broken part? Seems like the post would be machined in the brass part, not inserted separately.

    Kurt
     
  14. Dells

    Dells Registered User
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    Hi Kurt
    No I don’t have a picture of it as I have put it back together for now as I was not sure how to do it but it was a steel screw into brass corner post ( needless to say I didn’t break it) and there is a very small piece sticking out but not enough to get hold of.
    If that happens at work then I would mig weld a nut to it and the heat normally helps to free it but it’s to small to do that.
    Dell
     
  15. Ingulphus

    Ingulphus Registered User

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    Dell -

    A saturated solution of alum will dissolve the steel screw over several days (it won't affect the brass). I let the piece sit in a plastic or glass container in the oven, which has a pilot light that keeps it around 100F when not in use - optional, but I think the warmth helps speed up the process. I also use a cocktail stick to clean out the hole as the screw dissolves Patience is the key!

    Best regards,

    Mark Powers
     
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  16. Dells

    Dells Registered User
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    Hi Mark
    So just so I have got this straight, dissolve allum in water and just leave it to dissolve the steel, but you are saying it will not affect the brass, although the wife won’t let me use the oven, will hot water do ?
    Thanks Dell
     
  17. whatgoesaround

    whatgoesaround Registered User

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    I have dissolved steel like this; does not affect the brass so much that a polish won't make it look like new. I just let it sit out and, as said, use patience.
     
  18. Les Sanders

    Les Sanders Registered User
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    Well we can get them as small as 1/8" you may want to try a UK based Like Cousins.
     
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  19. Dells

    Dells Registered User
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    Hi Les
    I use cousins a lot I will give them a try if the alum doesn’t work but needs to be a lot smaller than 1/8th the screw is 2mm.
    Dell
     
  20. Wayne A

    Wayne A Registered User
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    Alum at room temperature works too. Watch for bubbles on the part, may have to pop them with a tooth pick to be sure the alum is making contact.
     
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  21. zzippy

    zzippy Registered User

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    Alum (Potassium Aluminium Sulphate / Sulfate). Potash alum,
    is it this that you use to corrode steel from brass
     
  22. Wayne A

    Wayne A Registered User
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    Have a small container from the grocery spice rack, says Alum on the front the ingredients are: Potassium Aluminium Sulphate.
    Its used for pickling and canning.
     
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