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How To Regulate The Time Of Your Grandfather Clock

Posted on October 8, 2010 | By clockde | 55 responses

If your grandfather clock is running slow or fast, it is easy to adjust and regulate it.

Grandfather Clock Pendulum

Grandfather Clock Pendulum

Changing the speed of timekeeping is accomplished by moving the pendulum disk up or down. The pendulum disk is moved up or down by turning the adjustment nut.
Move the pendulum disk by turning the adjustment nut to the left to slow the Grandfather Clock down.
To speed the Grandfather Clock up, move the pendulum disk by turning the adjustment nut to the right.

Day One
1. Select a time of day that will allow you to check your Grandfather Clock simultaneously for at least six days.
2. Record the time selected.
3. Check the correct time.
4. Re-set the minute hand to the exact, correct time.

*** IMPORTANT: You need to set your clock with another that indicates seconds, or if you are using a smartphone or VCR, set your clock when the time advances from one minute to the next. Failure to do so may give you poor results as you will not know what portion of a minute has passed when setting your clock.

Day Two, Three, Four, Five, Six (If Necessary)
1. Check the correct time.
2. Compare the time shown on your Grandfather Clock with the correct time. Is your Grandfather Clock fast or slow?
3. Turn the adjustment nut on the pendulum one complete
revolution for each half-minute fast or slow per day. (24 hours).
4. Check the correct time.
5. Re-set the minute hand to exact, correct time.

How it Works:
Turning the nut down lengthens the Grandfather Clock pendulum, making the clock run slower.

When you turn the nut up, you are shortening the Grandfather Clock pendulum, making the swing faster and increasing the speed of your clock.

Never turn the nut more than one revolution daily, or you may overcompensate.

Each time you make an adjustment, you should turn it less than the previous day.

 

If you have lowered the nut as far down as it appears and your clock is still fast, you should check to make sure the nut is properly fitting the slot on the bottom.

We have added advanced instructions on setting up your pendulum on the following page:

Adjusting and Setting up your Pendulum on your grandfather clock.

 

Posted in Clock Help and Instructions

55 responses on How To Regulate The Time Of Your Grandfather Clock

  1. I’m having problems regulating the number of chimes my clock strikes with the time on clock, it’s one strike behind.
    Any suggestions?
    Thank You,
    Linda Spears

    1. Hi Linda,

      Easy fix!
      1) When the clock comes up to the next hour, count the hour strike from the chimes.
      2) Move the hour hand (the short hand) to the number of the hour you had just counted.
      3) Move the minute hand to whatever the correct time is where you are at that time.
      Done! Sometimes it does take about an hour for the chimes to sync correctly, but this is how it is done.

      Good Luck,
      Robert
      **like or share us on facebook

  2. Hi,
    It is probably the pendulum length, though it could be a problem in the movement. Take out the pendulum and place it back up on a flat surface. Examine the nut and the threaded rod to make sure it is all the way up. If you are truly at the end of the threads, make sure the bob (the round disk) is able to move up and down with the nut. If it is, you could place some type of a spacer (like another larger nut of any kind) slightly larger that can move freely up and down the rod, then place the original nut under that one which will raise the bob to a higher level. If this is original pendulum and the nut was at the top of the threads, I would really suggest finding a clock tech in your area, as it is probably something else.

  3. My grandfather made my grandfather clock and the pendulum disc does not move. It does have an adjustment screw on the bottom. It’s running about 15 minutes slow in 24 hours. Is there anything I can do for this. My grandfather has passed away so I can’t ask him about. Looking for some advice. I would love to get the time running correctly.

    1. Hi Becky,

      The nut at the bottom should raise or lower the round disk (the pendulum bob). It might be stuck, stripped or maybe someone glued it in place. You need to take out the pendulum and place it on a table. Find out where it is stuck and release it. The nut needs to go up at least 7 turns if the tread is like most other clocks. This should correct it for you.

      Good Luck,
      Robert

  5. Hi
    My grandfather clock is running fast and I have already adjusted the Bob to be as low as possible

  6. I just inherited a beautiful Howard Miller grandfather floor model clock, Can you tell me where I can get some information on operating procedures?

    1. Hi,

      You may download generic instructions for your grandfather clock at the following link. You may click the link to view.

      Grandfather Clock Instructions
      This should be very similar to what was packaged originally with the grandfather clock you now own.

      Thanks!
      Robert

    1. The thread varies with the clock design. Typically, the shorter the pendulum, the finer the thread. There is no correct spec for this. It makes it easier for the owner to set by widening the thread as the pendulum lengthens. Pitch?.. the threaded rod should be vertical.

    1. This would be difficult to tell unless we were able to look inside the grandfather clock movement. This usually happens on older clocks (over 20 years old) that have not be cleaned and oiled every 5 – 7 years. The chime side is probably dirty and not allowing the parts to turn within the movement. Cleaning and oiling should be done by a technician. There is no user fix for this one.
      Good Luck,
      Robert

  9. I have a Howard Miller 611-200 grandfather clock.. of the 3 weights one has a nut on the bottom the other 2 look similar.What are the correct weights (L,M R) for my clock and can incorrect weights be the cause of my clock running fast even after the pendulum nut (and disc) are set at the lowest position?

    1. Hi,

      If the clock is a 611-200, the weights should be marked on the bottom as Left, Center and Right. If not, the heaviest weight should be placed on the right (facing the clock). If the clock is running fast, it is most likely the pendulum and not the weights. Be sure to look at the lower diagram of the following page.
      https://www.theclockdepot.com/clocks-blog/adjusting-the-pendulum-on-your-grandfather-clock/

      Chances are the the nut is going down, but the “bob” (the round disk) is not following the nut when lowered. It might also be the bob is sitting on top of the nut. If this is a used clock, it may also be that someone replaced the pendulum with one of an incorrect length.

      Good Luck,
      Robert Pearson

  10. I cannot get my howard miller grandfather clock to keep accurate time. Been trying for over a year. I have been told that on mechanical clocks if you can get them between 1 or 2 minutes fast or slow a week that’s good. Do you agree or should it keep accurate time?

    1. Most pendulum grandfather clocks are capable of keeping great time if the pendulum bob is moving easily up and down the rod. If your clock has an all metal pendulum and is in a area where the temperature is relatively stable, you should be able to get it close. It takes some patience. I had one where it stayed accurate within seconds a month. This really deserves an article on it’s own, but briefly:
      1) Set the clock exactly to the correct time to the second.
      2) Check it again EXACTLY 24 hours later and record the discrepancy.
      3) If you are within a minute, make no more than a 1/4 of a turn on the nut in the direction you need and reset the time.
      4) Check it again EXACTLY 24 hours later and record the discrepancy.
      5) If it is closer, turn the pendulum nut less than before in the same direction as before.
      Repeat until you are pleased.

      This should make a dramatic improvement in the accuracy of your clock. Let me know how it works out.

      Good Luck!
      Robert Pearson

      1. It has only taken about over a month and like you said a lot of patience but I think you had it right. So far it seems to be keeping pretty good time. Thank you

  11. I have a cable driven howard miller grandfather clock and every time I wind it the clock looses about 20 to 25 seconds. It catches back up by the next day. Is this standard procedure for these type of clocks?

  12. I just acquired a Colonial of Zeeland Grandfather clock. It chimes 2 minutes faster than the dial. Keeping accurate time. Any ideas?

    1. Hi Kathy,

      The clock should be oiled or cleaned and oiled every 5 – 7 years. The old oils become more like glue than oil when they decompose and get dirty. Sounds like your chime hammers are trying to move through the sludge of the old oils. I would suggest getting a good cleaning and oiling and I bet it would be fine.

      Good Luck…Robert

  14. Hello, I have a grandfather clock from about 1910. It has the kind of mechanism that requires the clock to be leveled to run properly. The way it keeps time changes constantly. I get it properly adjusted and it keeps great time for a few weeks, then it either slows down or speeds up and I have to adjust it again. What would make this happen? Temperature? the moon?
    thanks for any ideas.
    Marilyn

    1. Hi Marilyn,
      It is possible the nut under the pendulum is slipping due to stripped thread, but doubtful. If your pendulum stick is wood as many were during that time it was made, this is common. It expands and contracts with temp and humidity and changes the length. It is not the moon.:)
      You can replace it with an all metal pendulum, but it is considerably less costly to correct the time once a week when you wind it. You would also want to keep your wooden pendulum as a metal pendulum would also take away from it’s antique value.
      Good Luck!
      Robert

  15. Hi Robert,
    We have inherited a Mason & Sullivan that was handcrafted by my wife’s grandfather in 1965. Having a very hard time leveling, and time is constantly fast. Nut and pendulum are all the way to last thread. Bob moves freely down. Any thoughts? We also have inherited many other wall and mantle clocks as well as 2 Atmos clocks which are amazing!

      1. The Bob is moving freely and is traveling with the nut and the pendulum seems to be hung correctly. What else could it be?

  16. Hi Robert, the clock does have wooden pendulum stick, and that does make sense. I suspected the temperature or weather but couldn’t really figure out WHY that would effect it (I didn’t REALLY think it was the moon). I will not replace anything, I really don’t mind fiddling with the clock, I rather enjoy it. It is a constant challenge to keep it as accurate as possible!
    best regards,
    Marilyn

  17. Hi
    My 30 hr grandfather clock is running 10 minutes fast a day and I have already adjusted the Bob to be as low as possible to the bottom of the screw thread. To be honest it does not seem to make a lot of difference if i wind the screw thread up or down. If it tilt the clock forward this seems to have more effect on the time. Any ideas

    1. Hi Martyn…It may be that you are lowering the pendulum nut, but the “bob” (the round disk) is not following the nut. You may see instructions on this to correct it at:
      https://www.theclockdepot.com/clocks-blog/adjusting-the-pendulum-on-your-grandfather-clock/
      Make sure the bob is moving up or down with the nut as it is rotated. Look at the illustration and make sure the nut is positioned on the back of the bob properly. This should work for you.
      Robert

  18. Hi,
    I have a wall clock that kept very good time for twenty five years with the half and full hour chimes accurate to the time. The clock had not been wound up while we were away and when restarted after setting both hands to the appropriate time we noticed that the chimes were always five minutes late. We have tried resetting several times without success. Is there an adjustment screw on the meconisium that will correct this?

    1. Hi Anthony, The page you need to see is at:
      Grandfather Clock Does Not Chime At Proper Time
      (click the link above)
      There is an adjustment on the back of the minute hand that will let you set the hand so it will be pointing straight up on the hour. You might think of it as “the clock is right, but the hand is wrong”. Following the instructions will place the hand back on where it should be and correct your issue. Good Luck…Robert.

  19. I just found an Ethan Allen grandfather clock model 3027 movement GJ built 1983. I have lowered bob as far as possible and it is still running fast. The nut fits inside the bob ensuring the bob follows the nut. I know it was transported without the pendulum nor weights being secured. I checked the attachment and it looks appropriate. Any ideas or to I head to a clock shop. Thanks for sharing your expertise.

    1. Hi Nick..If the nut is all the way to the bottom of the threaded rod and the round disk (the bob) is also moving down and resting on the nut it should be slow, but your clock is fast. My guess is that there is something not right on the pendulum hanger which is making the pendulum hang higher than it should be. Good luck! Robert
      The following image should help.
      Pendulum hanger diagram

  20. Robert- Thanks very much for the information. I inspected and disassembled the hanger. Everything looked appropriate and fully seated. The clock still runs fast so I am going to attempt to fabricate a hanger extension to artificially make the pendulum longer. If it works I’ll let you know how I did it! Thanks for sharing your expertise with all of us.

  21. we inherited a grandfather clock that we moved to our home. I’ve gotten it to stay running but it picks up time after a couple days. What can I do to correct?. There is an adjustment that lowers the pendulum. Do you think that will do the trick?

  22. Thank you for this excellent site about GF clocks!
    –
    With my GF, the pendulum stick is wood and the bob is snug on the shaft and needs to me gently ‘pushed’ up or down to get it to move – just turning the regulator nut is not enough. I loosen the nut a little and then carefully move the bob while supporting the shaft to avoid damaging the suspension spring. With the bob in its new position, I retighten the nut a little bit and the bob stays in the new position.
    –
    I have the clock on a carpet floor with the clock setting on a solid marble base. To prevent the case from swaying, I’ve placed 3 wooden balls (approx 1 inch diameter) under the marble to form a solid tripod between the carpet and the marble – that makes the contact patch very small and prevents the marble from ‘floating’ on the carpet. Using the marble base and 3 balls works better than with the 4 feet of the clock directly on the carpet (smaller contact area).

    Jay Kosta, Endwell NY USA

    1. An update to my earlier comment –
      Another concern regarding case sway is the overall stiffness of the case – with a tall case clock, the base might be on a solid footing, but the top of the case might still be able to sway due the flexibility of the case itself. I think the recommendation to attach the case to a wall has the goal of preventing that type of sway. I did not want to physically attach the case to the wall, so instead I used a wedge-shaped block of foam insulation to gently bridge the space between the wall and the rear of the case top. I used a piece of foam insulation (the type that wraps around large hot water pipes) – cut a piece slightly longer than the gap, and cut one end at an angle so the flat end of the insulation is against the wall and the angled end sets on the top back edge of the case. Just having the foam setting between the case and the wall seems sufficient to eliminate visible swaying of the weights – the foam does not need to be compressed between the case and wall. Doing this has made the clock run at a more consistent rate, regardless of the position of the weights.

  24. My grandfather clock chimes the hour on the half hour. How do I get it to chime on the hour?

    1. Hi Kenneth.. You will need to wait until the half hour when it counts the hour and stop your pendulum. Then remove the minute hand and reposition it to point to the 12:00 position. Reinstall the hand nut and that should do it. If your hour count is wrong on the next hour count, move you hour hand to the correct hour it counted. Good Luck! Robert

  25. Can I use a light lubricant such as wd40 to oil the clock as the oil I have is very old and looks a bit to thick?

    1. Hi John…You never use WD40 on a clock movement. It might make a sluggish clock start working again for a while, but once it is on the movement it makes a mess. Then you may have to take it to a tech and if you need to place it in a vat of cleaning solution, it will ruin the solution which is another cost. Take out the movement from the case and clean it by hand….then reoil with a clock oil. You should use a synthetic, non-migrating clock oil. You can purchase it from Merritts.com
      Good Luck…Robert

  26. I’ve been working on a grandfather clock that a friend gave us, and I finally got it working, however it still loses about a minute every day even though the pendulum bob is raided all the way. Are there any other adjustments I could make to get the pendulum in the right range?

    1. Hello John,
      Make sure the disk (also called the “bob”) on the pendulum on your grandfather clock is rising upward when you adjust the nut on the bottom. We have some additional instructions for how to setup your grandfather clock pendulum at:
      https://www.theclockdepot.com/clocks-blog/adjusting-the-pendulum-on-your-grandfather-clock/
      This helps explain how to set up your pendulum so all parts are moving. This should get it going for you.
      Good Luck, Robert

    2. A problem is that you don’t know what has changed from when the clock was running properly.
      Perhaps the pendulum rod itself is too long – maybe it’s a replacement for one that was broken or lost. Might even be something like the suspension spring being too long. Or too heavy of a bob.
      If you modify any parts, go in very small increments. And try to be able to restore things back to how they were.

  27. Okay I have a Ridgeway Grandfather clock and am trying to speed it up. When I turn the nut at the bottom of the pendulum all it does is tighten up and never moves the pendulum or down. It has a lyre not a long rod.

  29. I have tried to adjust my grandfather clock pendulum the way that is showing in the pictures but it goes faster when I adjust it down and slows down when it adjust up

  30. my chimes are Dull and Sharp. The lasting ring does not happen with all but one. What can I do to adjust the chime sounds

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