Old mantel clock running slow

Discussion in 'Clock Repair' started by rowant, Jul 10, 2019.

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  1. rowant

    rowant New Member

    Jul 10, 2019
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    Hi all,

    Apologies if a similar question has been asked elsewhere, but I can't find anything. I recently inherited an old mantel clock and I'm trying to get it working properly. It had been allowed to wind down and stored away since at least 2012, possibly longer. I gave it a deep clean and bought a winding key off the internet to get it in working order again. I realised to get the mechanism working I needed to 'kick start' the horizontal circular spinning pendulum (picture attached, the spinning weight is the small silver mechanism at the top left of the main brass mechanism), and this has broadly got the clock working again.

    The only problem is that it seems to be running slowly, and is losing about 5 minutes per day. I read online somewhere that there are sometimes things that can be turned by a screwdriver to affect the beat of the clock and speed it up or slow it down. The only thing I can think this would be is the small silver thing under the spinning weight on this picture, but the screw is very stiff so I don't want to break anything by forcing it to turn.

    Would anyone have any idea if this is the correct way to adjust the beat, or if I'm missing something else obvious? Any help would be much appreciated as it has huge sentimental value to me, and my late grandfather who it originally belonged to would be happy to know it is working and in pride of place above the fireplace again.

    Thanks!

    20190710_190113.jpg 20190710_201805.jpg
     
  2. R. Croswell

    R. Croswell Registered User

    Apr 4, 2006
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    Please explain what is a "deep clean". If you did not completely disassemble the movement then it isn't really clean. It probably also has significant wear and perhaps failing plating on some pivots. A number if things can cause a clock to run fast or slow but I caution you not to attempt to adjust the problem away until you know what is really causing the problem.

    RC
     
  3. rowant

    rowant New Member

    Jul 10, 2019
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    Apologies, deep clean may be misleading, I didn't do anything to the internal mechanism, I just took a lot of dirt off the exterior.
     
  4. tracerjack

    tracerjack Registered User
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    If it's been stored away since 2012, then the movement will be dirty and dry of lubricant, the most common reasons why a clock performs poorly. If there was a lot of dirt on the exterior, requiring you to deep clean, you can be assured there is dirt on the inside. And as RC states, the movement is probably worn in places that will also rob power. So, trying to adjust the time through the floating balance may possibly work initially, but the best solution if you want the clock to run well is to have it cleaned, either by a professional, someone who works on clocks as a hobby, or jump into this as I have and have a great time learning how to clean and repair mechanical clocks yourself.
     
  5. mauleg

    mauleg Registered User
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    +1 for this, just be sure to include research for "floating balance" here on the boards before you get started.
     
  6. Organist

    Organist Registered User
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    This is a beautiful clock.
     
  7. shutterbug

    shutterbug Moderator
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    I agree with the above. It will cost you a bit to have the clock restored to working condition, but the sentimental value will be worth it. Most companies who made floating balances are gone now, so you don't want to do anything that would damage that part of the clock.
     
  8. gleber

    gleber Registered User

    Jun 15, 2015
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    I'll try to help with the education part. The beat is whether the pendulum or balance wheel swing is even. If the time between the tick and tock is not equal, it is out of beat. It should be tick-tock-tick-tock, not tick----tock-tick----tock. This will usually cause the clock to stop after a few moments because the pendulum or balance wheel is not getting the impulse it needs at the correct time during its swing. If the clock is running fast or slow, that is corrected by regulation. For a pendulum, the period is regulated by lengthening or shortening its length (longer = slower). This can be actual length or "effective" length (by raising or lowering the pendulum bob). For balance wheels, there are usually weights on the wheel that can be moved radially in or out. This has a similar effect as for a linear pendulum and changes the frequency of the beat (not the equal time between impulses, but how long a full cycle takes). So, in your case, the weights need to be moved inward, which would speed up the clock.

    Another issue with balance wheels is the amount of rotation for each cycle. If it is worn or dirty, the amount will be reduced. This can make a clock run fast, because the frequency will be shorter than if it is allowed to experience a full swing. Usually a full swing is about 3/4 or a rotation in each direction.

    Tom
     
  9. glenhead

    glenhead Registered User
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    Just to be really clear here, since you admit you have no experience in this stuff:

    The spinny pendulum thing with the coiled springs is called a floating balance. They do a really good job of keeping time when everything is running well. I find them easy to work on and set, but there are those who find them too finicky to mess with.

    There was a period of time a few decades ago when that particular kind of movement had chrome-plated pivots, the shiny doodads that stick through the holes in the plates. The wheels (gears) ride on arbors (shafts) with pivots on the ends. The chrome plating did a fantastic job of decreasing friction - until the plating started to flake off. Unintended and unanticipated consequences. Once flaking starts the pivot is shot and friction skyrockets. There are a whole slew of options for what can be done, from cutting off and replacing the pivots to installing miniature roller bearings to just swapping out to a complete new movement. Without being able to look at the pivot there's no way to tell 1) if it was plated or 2) if the plating is shot.

    Friction is the enemy of a timepiece. The spring you wind or weight you raise or whatever acts as the "engine" for the timepiece seems really strong, but once that power has gone through the train of wheels it's a tiny fraction of its starting strength - less than 0.2% even under ideal conditions. Friction in the train robs power, resulting in weak or perhaps no operation.

    If the clock was last serviced more than ten? fifteen? years ago, it was oiled with natural lubricants. Over time natural lubricants oxidize and dry out. A clock also gathers an astonishing amount of dust on the wet pivots, whether you can see it or not. All that stuff causes more friction. The best way to minimize that friction is to take the movement completely apart, clean it and fix anything that needs to be fixed, put it back together, and lubricate everything with the correct oil or grease. That obviously requires either knowledge or a lot of research (to do it without destroying things or hurting yourself). Note: WD40 or any other spray "lubricant" is NOT the right approach. Not, not, not.

    As people have recommended, if you want to be able to pass this little beauty to your grandchildren your best bet will be to find a clockmaker and drop the money to get it professionally overhauled. Or learn to do it yourself - there are several folks on the forums who have taught themselves. If you decide to do it yourself, be patient with the process. Rushing things will cause you nothing but grief.

    Hope this adds to the muddle. :)

    Glen
     
  10. gmorse

    gmorse Registered User
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    Hi Tom,

    In the vast majority of movements with balance wheels of some sort, be they clocks or watches, the frequency of the balance wheel is adjustable to a limited extent, (by the user if they feel the need), by altering the effective length of the balance spring, (the 'hairspring'). I think floating balances are an exception to this, but generally, altering the weights on the balance wheel is another subject altogether and isn't recommended for the casual user!

    Regards,

    Graham
     
  11. gleber

    gleber Registered User

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    I think that's true of the style with the spiral spring. This one has the floating spring and uses weights and an adjustment arm See:

    The Hermle Floating Balance Adjusting the Beat & Increasing the Speed (the style in this style)

    vs

    How to adjust the accuracy of a mechanical watch - page 2 (this is more like an alarm clock with a lever to adjust the "effective" length of the spring and hence its period.

    Tom
     
  12. R. Croswell

    R. Croswell Registered User

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    From your first referenced article, this quote should be emphasized; "Normally all adjustments are made at the factory. Do not make any alterations unless malfunctioning clearly indicates a specific problem". Normally there should be no need to add or remove weights on this floating balance. It is useless to attempt to adjust a worn out or dirty clock movement. When the rest of the going train is returned to good order it will very likely return to keeping time again.

    Here is another good reference on servicing and adjusting the Hermle floating balance: http://www.davesclocks.net/uploads/5/8/9/1/5891949/hermle_floating_bal_summary.pdf

    RC
     
  13. gleber

    gleber Registered User

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    Also, before removing or adding weights, the bold step should be attempted first:

    Timekeeping and regulating:
    x Use clutch assembly on top of balance wheel for minor adjustments (3 min per day).
    x Add or remove weights (in 180 degree opposite pairs) for greater adjustments (see diagram).
    x Add weights= slower x Remove weights=faster

    If adjusting the clutch assembly (what I called "lever" earlier and what they call "Regulator with disc" in their drawing) does not alter the timekeeping enough, I would look at other issues like requiring a disassembly and cleaning or inspecting for wear, etc. before removing or adding weights.

    Tom
     
  14. gleber

    gleber Registered User

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    In post #3 of this thread, you can see the Regulator with disc and the two weights that are moved in an out when the lever is rotated. This is the best photo I could find and don't have a clock with a floating balance wheel in my collection to take a better photo.

    Smiths floating balance escapement

    Tom
     
  15. rowant

    rowant New Member

    Jul 10, 2019
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    Thanks all for the replies - from what you've said I think it's best if I get it looked at professionally. Will add it to the to do list!
     

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