Sympathetic Vibration

[shutterbug]

I've read about it, but never seen it until recently. I repaired a early 1800's grandfather clock, and it was running fine for 10 days on my test stand. I delivered it, installed it in the case and set it up as it had been before. All was well for a month, but the customer called last week and said it had stopped. I made a house call and found it to be badly out of time, so made the necessary adjustments. We chatted for a few minutes, and I heard the clock stop again. I started it, and chatted a few more minutes while keeping my ear tuned to the clock. I heard a "clunk" as it stopped again. Opening the lower case, I noted the time side weight was swinging, and finally hit the pendulum. I stopped it, and started the pendulum again. After a few seconds, I detected the swing of the weight start and increase with each beat of the pendulum until hitting it and stopping the clock. I braced the case to the wall with a small piece of wood, which stopped the problem. Just adding this to the board to help others who are trying to identify similar issues with tall case clocks. If the customer does not want the clock secured to the wall, a brace is the next best thing.

 

[shutterbug]

I've read about it, but never seen it until recently. I repaired a early 1800's grandfather clock, and it was running fine for 10 days on my test stand. I delivered it, installed it in the case and set it up as it had been before. All was well for a month, but the customer called last week and said it had stopped. I made a house call and found it to be badly out of time, so made the necessary adjustments. We chatted for a few minutes, and I heard the clock stop again. I started it, and chatted a few more minutes while keeping my ear tuned to the clock. I heard a "clunk" as it stopped again. Opening the lower case, I noted the time side weight was swinging, and finally hit the pendulum. I stopped it, and started the pendulum again. After a few seconds, I detected the swing of the weight start and increase with each beat of the pendulum until hitting it and stopping the clock. I braced the case to the wall with a small piece of wood, which stopped the problem. Just adding this to the board to help others who are trying to identify similar issues with tall case clocks. If the customer does not want the clock secured to the wall, a brace is the next best thing.

 

[eskmill]

The problem, cause and cure you described is common among older long case clocks and especially so with tubular chime clocks that have only a cloth veil instead of a back board.

Years of handling, shipping, relocating weakens the case until it can no longer serves as a fixed suspension point for the pendulum.

In situations where the owner resists fastening the clock to a supporting wall, the clock case can be made more rigid by installing a metal strap "brace" on the back in the form of the letter X. The four ends of the straps are screwed to rear edges of the case sides and the point where the straps cross is rivetted tight. It makes the case rigid and not liable to wobble.

 

[doug sinclair]

I ran into that exact problem a number of years ago, with an early 19th century tall clock. I agonized over this clock while trying to determine what might be the problem. One day, I did exactly what shutterbug did, with exactly the same result. This clock sat on shag carpet, to make the problem especially bad. I solved it by building a base of 3/4" plywood with 4 "T" nuts installed from the underside, one on each corner, and 4- 2 1/2" bolts sharpened to a point at the tip. I installed the bolts, placed the platform where the owner wanted it, and drove the sharpened bolts through the carpet and the underpadding. Re-positioned the clock, and it has been fine ever since!

 

[ged]

My 9 Tube has a Ridgid wood case and back, I found boarded floor and carpet was the cause of sympathetic vibration, A metal brace would not have helped in my situation. I cut floor away and stood clock on Concrete base of house, Problem solved. I was at the time running clock with Hood off because of ceiling height,waiting for wife to decide where FINAL position of clock was going to be, it is now 6"in floor and hood is on. Can't sell house without clock. I can't post Pic' of Clock as I only know how to Email pic's, I have tried and failed miserably. Sad Old Pensioner arn't I?. Regards, Ged.

 

[Scottie-TX]

As recent as this week: Under test on an end wall I found the clock ran great so long as beat amp was connected. Removed the beat amp and it would stop EVERY time! Now this isn't "sympathetic" but rather an unstable case that could rock. The beat amp was stabilising the case and preventing it from rocking!

 

[doc_fields]

For what its worth: I had built myself a floor test stand out of 2x4's and 1x4's. Built it with levelers, etc. One thing though, I never braced it to the wall. When I got 2 or 3 granddads running on it, it became quite interesting. Weights swinging one way, pendulums another, the motion was almost hypnotic and sure knocked some out of beat. I am working on a Hershede 9 tuber, sits in a heavy traffic area, old thick carpet, floor creaks around it. I took the movement into the shop, been working great, so customer is relocating the case. When I used to do appliance repair (25 years of it), it was the same problem with washers set on carpet, especially since 1987 when Whirlpool came out with their new design. Its hard to convince people sometimes that its their floors that are the problem.......doc

 

[MARK A. BUTTERWORTH]

Although the discussion has involved antique and tubular clocks, the modern clock is at least as likely to have this problem since it is generally lighter.
Since many of the clocks are set out from the wall by the thickness of mopboard, we have shim material of that general thickness made from short lengths of the board from a lumber yard. On a modern clock the front levelers can be turned so as to force the top rear portion of the clock against this material placed against the clock and the wall. One can affix it to the top rear clock case by contact cement, velcro, etc. The homeowner does not generally object to that as he doesn't see it as something that changes either the clock or the wall.
It also reduces the motion of the clock from the patter of feet.
FHIW

 

[Neal Miller]

A solution I have found effective for providing a more secure base for a Grand Father on a carpeted floor is to pull the carpet up in the area where the clock stands, cut out a piece of padding a little larger than the footprint of the clock and fill the area with a piece of 3/4" plywood. This increases the stability of the clock, but does not change the appearance of the carpet.

This fix is not as effective as attaching, or leaning the clock to the wall, but it is much better than leaving it on the padded floor.