Strike the Gong

Discussion in 'General Clock Discussions' started by gleber, Aug 15, 2019 at 9:39 PM.

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  1. gleber

    gleber Registered User

    Jun 15, 2015
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    Is there an ideal place to strike a typical gong (coiled or straight)?

    Also, sometimes the gong sounds nice, and others, clangy or dull during the same strike cycle. I think it depends on the point of vibration when the hammer hits. Is there any way to ensure it sounds consistently nice?

    Thanks,
    Tom
     
  2. Isaac

    Isaac Registered User

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    Usually the straight area right before the coiled gong starts to coil is the sweet spot in terms of sound. Make sure the hammer is hitting the coil straight on.

    Some gongs are just built cheaper than others, and will sound pretty bad no matter what you do to them (I'm looking at you, kitchen clock wire gongs)
     
  3. gleber

    gleber Registered User

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    Yes, certainly some gongs are much better than others, but my question is some strikes on the same gong are much better than others - what causes this and can it be controlled?

    Tom
     
  4. Uhralt

    Uhralt Registered User
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    I think this is related to the fact that the gong is still vibrating (causing it to slightly move) when the next strike hits. So the distance between hammer and coil is not consistent. You will find that the first strike usually sounds fine and then mixed results follow. You can minimize the effect by finding a spot for the hammer to strike where the gong moves least and by slightly increasing the distance between gong and hammer. Slowing down the strike also helps.

    In my experience it is not always possible to make the effect go away completely, you can only minimize. BTW, the same effect is true for bells, too.

    Uhralt
     
  5. chimeclockfan

    chimeclockfan Registered User
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    On gong rods the hammer is usually positioned right before or after where the tapered neck begins. Most ideal sound quality is achieved and the rod won't whip around excessively when struck.

    The consistency of hammer blow is more dependent on the hammer design rather than the type of gong. I think the most stunning example of hammers for gong chimes would be this 'Peerless' M. Bäuerle weight driven clock with adjustable tension springs on each chime hammer.

    peer10.jpg
     
  6. gleber

    gleber Registered User

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    I agree with the distance, but I think it is more that the hammer will either be in phase with the vibration, or out of phase, which will change the tone.

    The minimal vibration amplitude will be at the base or mounting point of the gong, but I don't think it works well when hit there. That is the reason I asked about ideal spot to strike.

    I think I understand the general physics, but was mainly wondering if anyone has studied this in detail or has any recommendations based on the study or at least empirical evidence. Isaac - is there any logic or consensus behind your recommendation?

    Tom
     
  7. gleber

    gleber Registered User

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    Thanks for the added info Chimeclockfan. It is interesting to see the effort different manufacturers went through to optimize (or claim) superior quality.

    On coiled gongs where the hammer strike spot seems to be further from the block than on straight gongs, I think the location does lead to more "sour" notes. In the coiled gong, the spot is farther from the block and movement at that spot is larger and I think it would be very difficult to synchronize the strike with the phase and position of the gong. And, then you would have to account for different speeds when the spring is wound or loose (not an issue for weight driven), and how clean the clock is. Both of these would affect the speed of the train and the ability to snyc with the gong frequency.

    I'm also sure the hammer tip material and its condition, hammer weight, spring tension, etc. have a significant effect, but I'm trying to focus on a specific (but undefined) gong / hammer and how to optimize it's performance (assuming these other factors like hammer tip condition are in good shape).

    Tom
     
  8. upstateny

    upstateny Registered User

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    Tom, I have had a similar problem with a Waltham coiled gong. Which I suspect is what you are working on. I found:

    Waltham coiled gongs are attached to a large brass block which is threaded onto a long post which is attached to a base bolted to the back board.

    Make sure that the block is attached firmly to the post.

    The hammer distance can be adjusted in tro ways 1)by adjusting the heighth of the post 2)by sliding the hammer along the hammer rod.

    Some Walthams use a hammer with a non-removable metal striking surface and others have with a removable round leather end. The length the leather projects from the hammer will exacerbate the problem, usually on every other strike.

    I have found that how hard the leather is will also give you a headche.

    I agree that the flat portion of the gong closest yo the top will provide the best sound. Gongs on the Walthams I have worked on have about a 1 inch sweet spot.

    I will send you a PM with a phone # you can call to discuss.

    Tim
     
  9. Chris Radano

    Chris Radano Registered User

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    I apologize if this is a little off topic. Here's a clock gong situation.
    This Scottish bracket clock doesn't strike the "sweet spot" consistently, except for the first strike. The clock has a slow strike, but the hammer hits the gong so hard, the entire gong visibly vibrates maybe about 1/2-3/4". So, sometimes the gong is vibrating so much, the hammer may not hit it straight on for the rest of the striking sequence. Many times, at the end of the last strike, the gong bounces up and reverberates on the hammer (which my wife doesn't like).
    The clock strikes so hard, a replaced piece of glass on a side panel loosens and vibrates against the case (again the wife doesn't seem to like). Can't seem to get the glass to stay tight. It's loose now after a few years when I last tightened it. If anything is resting close to the clock on the table top, that may vibrate, too.

    Jas. Muirhead Glasgow 001.JPG Jas. Muirhead Glasgow 005.JPG
     
  10. rmarkowitz1_cee4a1

    rmarkowitz1_cee4a1 Registered User
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    This all reminds me of that T Rex song.

    bang-a-gong-and-get-it-on.jpg-e1456960145793.png

    And CR thought he was off topic?

    RM
     
  11. gleber

    gleber Registered User

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    Thanks for the interest. My question is generic, not specific to any clock. My recent Waltham has a single tube for the strike and it sounds nicely normal. I have several other clocks with gongs and some are good, some not so good. I just want to learn how to optimize the set up to get the best quality sound they have to offer.

    Tom
     
  12. gleber

    gleber Registered User

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    If I didn't know you were in PA, I would think your neighbors might suspect earthquakes.:D

    Is there no way to reduce the spring tension on the hammer?

    Tom
     
  13. gleber

    gleber Registered User

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    Ha, I missed an opportunity for a catchy thread title.

    Tom
     
  14. Time After Time

    Time After Time Registered User
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    Is there any room to place small amounts of clear silicone caulk at various points around the glass, perhaps from inside the case? I know, use of modern materials on an antique clock is not canon, but if small amounts are used (recommended) it is easily reversible. Depending upon the space available, perhaps you could use something more period appropriate to isolate the glass and dampen the vibration.

    It sounds to me like you'll just have to tune each clock as you might tune an instrument. Each one is unique. Rules of thumb may give you a good starting point, but you'll have to listen to assess what's going on and take steps to improve the sound to your ear. Chances are pretty good that by the time an Antique crosses our bench, the hammer(s) have been "adjusted" many times already.
     
  15. Chris Radano

    Chris Radano Registered User

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    Yes, I was trying not to use modern materials, and keep it reversible. Because the replacement glass isn't the exact fit, I put a small shim between the glass and the oak small molding strips inside the case. The molding strips are fastened with small wire nails, and I added a small amount of glue. That lasted a couple years. I will look at it again, maybe I can use silicone as a "shim", not to seal the glass in place so it is reversible.

    It's just funny with this clock, how strong the vibration is. I think it would be considered a 3/4 size case, but the movement is full size. I didn't realize how much vibrating occurred with the gong until I saw it striking inside the case. Quite a lot of activity. The sound is like a tower clock similar to Big Ben in the distance (at least when it hits square on).
     
  16. gleber

    gleber Registered User

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    With a description like that, you need to share a video.

    Therein lies the rub, and the reason why I started this thread, but I'm beginning to think we're destined to live with clangy gongs unless they are so slow that the vibration dies out before the next strike. I do prefer a slower rate - sounds more like a church bell.

    Tom
     
  17. Time After Time

    Time After Time Registered User
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    I'm sure you'll come up with a good solution to the problem. Good luck and please share your solution with us if you have the time and inclination to do so.
    Maybe there are some approaches in the archives which may give you ideas or perhaps someone else will see this thread and weigh in.

    There is a solution Tom. You can make your own clock with dampening in addition to normal striking as Dave Weisbart did:

    Other than that, I suppose we just have to tune and perhaps try different hammer insert material. Maybe try to slow the strike down while leaving enough power to run the train for the full design run time between windings... Please let us know how you solve the problem.
     
  18. Arthur Cagle

    Arthur Cagle Registered User

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    Tom, all of the above comments being true enough, adding a soft piece of leather to the hammer should lessen the vibrations of the gong, therefore the duration of the vibrations, so subsequent strikes may hit a vibration free coil. You may rename me "Captain Obvious," if you wish, as you no doubt thought of this. Or perhaps I'm wrong...wouldn't be the first time!
     
  19. gleber

    gleber Registered User

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    Thanks Bruce - that video was the kind of information I was looking for - a little on the scientific side. I tried damping the gong with my finger after each strike. It sounds terrible, I think because we are used to hearing a gong or bell resonate for a while. When it stops abruptly, it just doesn't sound right. Perhaps if it could be timed better than manually, more like in the video, and stop just before the next strike, it may sound a little better.

    Thanks Arthur - The main clock of my experiments (but not the only reason I asked this question) has a leather tip, but it could probably be replaced with newer softer one and I agree with you, it might sound better for single notes (1 and 1/2 hours) and sequential strikes.

    Tom
     
  20. Chris Radano

    Chris Radano Registered User

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    Here is James Muirhead of Glasgow striking 11:00. Keep watching until after 6 or so, the wire becomes increasingly active. The hammer head still has it's original tip of what appears to be hardened leather. It's winding day today, so the spring is getting relaxed, although the fusee keeps it strong. After I wind, the strike is slightly faster for approx. 12 hours.
     
  21. Isaac

    Isaac Registered User

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    Wow, that's quite some movement. Interesting that the gong block itself doesn't move much.
     
  22. gleber

    gleber Registered User

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    That's a massive hammer! I get vertigo just watching that gong vibrate.:eek:o_O:confused:

    Tom
     
  23. Chris Radano

    Chris Radano Registered User

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    I exaggerated, the range of vibration is more like 1/4-1/2". Mostly on the inner coil. I could have sworn the top of the gong moved more. I know sometimes the top moves more, you can hear it reverberate on the hammer head.
     

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