Help Pendulum too long (case too short?)

[ssohner]

This is the second crystal regulator where I have had this problem, both Ansonia. The clock runs well, is in beat, but gains time. I have lengthened the pendulum to the point where it is nearly touching the bottom of the case. Is this a common problem or a case of the wrong pendulum?

The other crystal regulator keeps better time after I made what I think was an unusual modification. I added lead pellets inside the "fake mercury" capsuls to lower the center of mass. But I have never seen that proposed on this forum as a solution to this kind of problem.

Are those hollow metal tubes that are meant to represent mercury supposed to be solid? How did the originals come from the factory?

 

[Evernia]

Have you changed the suspension spring? A thinner one might be worth trying.

 

[R. Croswell]

I believe the pendulum originally came with mercury, which is heavier than lead. If the cylinders are hollow I would fill them with lead shot and see how is goes.

RC

 

[bruce linde]

keep in mind that it's the center of mass that defines pendulum length... you could have a 4" tube tube filled with 3" of mercury that would be heavier than than the same tube filled with 2" of lead... but the lead-filled one would run slower as the COM is lower.

 

[Uhralt]

keep in mind that it's the center of mass that defines pendulum length... you could have a 4" tube tube filled with 3" of mercury that would be heavier than than the same tube filled with 2" of lead... but the lead-filled one would run slower as the COM is lower.

Not necessarily. It depends on how much mass is on top of the tubes. if the top is heavy, you will still lower the center of mass by filling in more lead. If the top is light, your scenario will apply.

Uhralt

 

[ssohner]

Thanks everyone. The only thing I could imagine was to lower the center of mass without lengthening the pendulum any further. I don't have another suspension spring to try.The spring and hanger rod is one piece on most of the American crystal regulators.

I guess I will try the lead pellets. I just had never seen that suggested before.

It seems that converting these clocks from mercury capsules to fake ones would be a common problem if they are designed to run so close to the bottom of the case.

 

[Bruce Alexander]

Assuming that the movement and escapement are working properly, that may not be the original pendulum.

Ansonia did not use real mercury in their Crystal Regulator Pendulums. At least I've never seen an example of it. How much does the pendulum weigh? After checking the suspension spring as has been suggested, it would seem that lead shot in the simulated mercury inserts would be a practical solution to work with what you have on hand.

Good luck with it.

Bruce

 

[ssohner]

Yes, the only ture mercury pendulums I have come across have been on french clocks and they are few and far between. I own only one like that and I occasionly see them at auctions. In those cases the auctioneer will generally caution that they cannot be shipped due to being hazardous material.

 

[Fitzclan]

Another possibility would be to use a suspension spring with a longer feather. You will have to raise the pendulum slightly just as long as it clears the bottom of the case. This will give you a wider swing and slow it down a bit.

 

[Bruce Alexander]

He shouldn't have to jump through hoops here. I really think that there's a good possibility the pendulum is a replacement.

 

[ssohner]

Is it the thin, wide, flat area that you are calling the "feather"? (the image is not my part, it is from Timesavers catalog).

 

[Fitzclan]

Yes. Timesavers sells suspension rods where the feather is part of the leader. In other words, The leader is hammered into a feather so it’s all one piece. Part #18918. The feather on these is about 2” long. Part #17825 has a 2 1/4” long feather.
Often when a clock has a spot for the pendulum to show in the glass, the pendulum hangs too high or too low and you can finagle the suspension by using different length feathers until you get it showing properly and keeping proper time.
I think the one piece feather is .005 thickness. You may be better off with the second one which is .004. Either way you can always sand the feather to thin it down. Good luck.

 

[svenedin]

Yes, the only ture mercury pendulums I have come across have been on french clocks and they are few and far between. I own only one like that and I occasionly see them at auctions. In those cases the auctioneer will generally caution that they cannot be shipped due to being hazardous material.

I have a French Four-Glass by Marti with real mercury in two tubes in the pendulum. It has a Brocot escapement and a rate adjuster on the dial. I believe the clock was meant to appear as if it had a compensated pendulum. It isn’t a proper mercury compensated pendulum though -I have one of those in a long-case. It does look pretty though with the mercury reflecting the light around all the glass.

To the OP: how did you adjust the pendulum length? Did you use the dial rate adjuster (use a pocket watch key) or did you adjust the actual bob? Or both?

 

[ssohner]

I initially used the rate adjuster and thought I was going the wrong way (counterclockwise) because it continued to gain time. On closer inspection I discovered that the horizontal adjustment nut was at the top of the threads and not moving down. I adjusted the nut lower and moved the pendulum higher on the rod to give me some working room on the adjuster. As I continued to move the adjuster lower to compensate for the time gain I had to move the pendulum back down as low as possible on the rod, but I reached the point that it was hitting the floor of the case. The clock is almost timed but still gains about a minute per day.

I am hoping that lowering the center of mass will put it right.

 

[MARK A. BUTTERWORTH]

If you are adding lead to what is there already you could be raising the center of mass and making it go faster. It depends on where the center or balancing point was before you added the lead

 

[ssohner]

Mark,

Point well taken. I have not had the pendulum apart yet. My proposed hairbrained solution is predicated on the assumption that the thin metal decorative tubes inside the glass tubes are empty. I will have to disassemle the pendulum to discover whether that assumption has made an a** out of me. Time will tell.

 

[bangster]

What Mark said. To make it run slower, you need to lower the center of mass ("balance point"). If the current balance point is below the hollow tubes, filling the tubes with shot will raise the balance point, and make it run faster.

 

[Bruce Alexander]

The center of mass won't be below the vials. but you may not want to "fill" the simulated mercury inserts. If the simulated mercury is a solid metal rod, you'll have to rethink your approach. Timesavers does carry parts for these types of pendulums but what they offer may not fit your pendulum's glass tubes.

I actually machined a lead rod to modify a client's non-factory Crystal Regulator Pendulum several years ago. It fit inside of the shiny simulated Mercury insert. As you can imagine, the lead is pretty soft and doesn't machine well but I was able to get it reduced enough to fit. It cuts and bends pretty easily. Being a solid form, it was as dense a material as I could work with.

Even so, the desired BPH was near the end of the regulator and pendulum's range of adjustment. It worked well enough but that's not ideal.

Please let us know how things work out.

EDIT:

I can't see all of your clock but from what I can see, it looks like you have a model Ansonia called the "Zenith".

FWIW: Tran Duy Ly's catalog illustration shows the Zenith with one of their more ornate and substantial pendulums.
That style of pendulum is shown in this auction listing: Ansonia "Zenith" Crystal Regulator - Jun 11, 2019 | William Bunch Auctions & Appraisals in PA

I see other examples online with the less ornate simulated mercury pendulums, like yours, but there's no way of knowing if those pendulums are original to the clock.

Bruce

 

[ssohner]

Bruce,

Thanks for the link. I did some sluething on the internet and found the attached image on Pinterest. It is a dead ringer for my clock (except for the pendulum). The bottom piece of the pendulum appears to be a solid casting that matches the motif of the case. That probably accounts for the lower center of mass. My replacement pendulum is most likely lighter overall and has a higher center of mass. I wish I could find a picture of the complete pendulum.

My clock, still unmodified, and with the adjustments I described above, is only gaining seconds a day, so I don't think it will take much added weight at the bottom to make it go the other way. Will let you all know.

Steve Sohner

 

[ssohner]

I found another image of the Ansonia Zenith on this very forum from a couple years ago.

Ansonia Crystal Clock

 

[ssohner]

Finally got around to disassembling the pendulum.
Someone had already filled the metal tubes full of lead. In order to lower the center of mass I decided to cut the lead slugs in half, keeping the weight at the bottom of the tubes.
I reassembled the pendulum using only the bottom half of each lead slug and without changing the position of the pendulum on the rod.
.
Now without changing anything else I will monitor the clock to see if it gains or loses time over the next few days.

Steve Sohner

 

[bruce linde]

What Mark said. To make it run slower, you need to lower the center of mass ("balance point"). If the current balance point is below the hollow tubes, filling the tubes with shot will raise the balance point, and make it run faster.

uh... see post #4.

 

[ssohner]

Not sure I understand your comment. I did not expect to find lead in the pendulum tubes. This is the first time I have taken it appart. I removed half of the lead that someone else had put there.

In my mind that has lowered the center of mass.and should make the clock lose time. Do you think I am wrong about that?

Steve Sohner

 

[bruce linde]

steve - if you're referring to my comment, it was directed at bangster who apparently didn't notice that i had said essentially the same thing previously. if you can't rag your fellow admins, who can you tease?

you did exactly the right thing and i bet it's working... yes?

 

[Uhralt]

Finally got around to disassembling the pendulum. View attachment 602524
Someone had already filled the metal tubes full of lead. In order to lower the center of mass I decided to cut the lead slugs in half, keeping the weight at the bottom of the tubes. View attachment 602525
I reassembled the pendulum using only the bottom half of each lead slug and without changing the position of the pendulum on the rod.
. View attachment 602526
Now without changing anything else I will monitor the clock to see if it gains or loses time over the next few days.

Steve Sohner

There is a simple way to roughly determine the center of mass in these short, stiff pendulums. Just bring the pendulum in a horizontal position and, by putting a fingertip or similar support under the center rod, find the point where it is balanced like a scale. The support point is the center of mass. Now change the lead filling, make sure it sits at the bottom, and repeat test to see if the center of mass is now higher or lower. This test gives you also an idea how much your center of mass has shifted.

Uhralt

 

[ssohner]

Sorry Bruce, I jumped the gun. I did not notice that you were directing your comment at Bangster. Thanks for the feedback.

You are correct. During the approx. 18 hours since I put the clock back in service it has lost almost 2 minutes, So I am confident I can regulate it properly.

Uhralt, thanks for the tip. I wish I had thought to balance to pendulum on a pencil or something and take a photo before and after. It would have been interesting to see the difference.

Steve Sohner

 

[Uhralt]

Sorry Bruce, I jumped the gun. I did not notice that you were directing your comment at Bangster. Thanks for the feedback.

You are correct. During the approx. 18 hours since I put the clock back in service it has lost almost 2 minutes, So I am confident I can regulate it properly.

Uhralt, thanks for the tip. I wish I had thought to balance to pendulum on a pencil or something and take a photo before and after. It would have been interesting to see the difference.

Steve Sohner

When the clock loses time now you have obviously done the right thing!
Just one additional remark with regard to the test: Once you determined the center of mass, any mass added above the center will speed up the clock, any mass added below the center will slow it down.

Uhralt

 

[Bruce Alexander]

I think you had it adjusted to as slow a beat as possible before.

The fact that you'll need to regulate for a faster BPH now is good.

You definitely want to be able to adjust in either direction.

 

[Carl Bergquist]

I have three of these running just fine and they all have more that a quarter inch of clearance. None of these have weight in the chrome tubes. I would try to gain the necessary length with the upper adjusting mechanism. Mine has almost a half inch of movement between top and bottom. I just went back and looked and one of mine is the second style of pendulum and it does have more clearance that the other two. If you can't resolve this let me know and I could measure my three from the bottom plate to the bottom edge of the adjuster. That measurement would tell a story.

 

[Carl Bergquist]

I was just too curious, I measured all three. !92 mm, 192 mm, 191 mm. All three have about 1/4 inch of clearance off the case and some thread left on the adjusting nut so I could still slow them down a bit. I don't wind these all the time so I can't tell you how close to "perfect" they are but they are ok to my standards and they are not filled with lead. I think yours will probably measure the same as mine otherwise the doors would fall off or not close. Did someone tinker with the escape wheel or change out a gear? Something is fishy.

 

[ssohner]

Thank you Carl. I currently have a post in the "Parts Wanted" forum for the correct pendulum for this clock. I don't know if I will find it.

The rate adjuster is not at the top or bottom of its range but it is closer to the top. For the time being I am going to be able to adjust the rate.

I am becoming convinced that my pendulum is a generic replacement. I am guessing that different versions of this type are taller or shorter than my mine. So another solution I was toying with would have been to shorten the glass tubes and the posts on either side to lower the top horizontal member of the assembly. That was going to be a lot more work with less likelyhood of succfess. I think I took the easy way out for now.

It would be interesting to know how tall your three different pendulums are. Mine is 2 1/8 inches.

Steve Sohner

 

[Carl Bergquist]

The two pendulums that are like yours measure 2.1 in. and 2.1 in. which is essentially 2 1/8 in. Your pendulum is good. I have no idea why yours was loaded with lead. Maybe someone thought it would duplicate the weight of mercury. Others have said that Ansonia never used real mercury, my three are empty chrome cylinders with domed tops. I also have a Waterbury crystal regulator with a pendulum closer to the looks of yours but it is different enough that we won't confuse the two. Also, the total length of all three pendulums is just under 5 inches

 

[ssohner]

So two weeks and four days since I made the modification to the pendulum and the clock is keeping good time. It gains about a minute per week. I have discovered that the available adjustment range on the rate adjuster is about 1/4 turn. Not much leeway. But at least the mod has resulted in a clock that keeps time.

Based on Carl's suggestion I am still trying to figure out how to measure from the bottom of the case to the bottom edge of the rate adjuster. I don't have a scale just the right length to fit inside the case.

 

[Carl Bergquist]

I cut a piece of balsa about 3/8" wide and a little longer that it needed to be. It fit inside the case between the gong and pendulum. I cut it to length on the first clock and tested it against the other two. Didn't have to take anything apart. Yours almost has to be the same. As I said before, your doors would not close. I am not going to tell you what to do, but I would take all of the lead out of those glass tubes and just use the chrome cylinders. If it doesn't help it is easy to undo. Get the lead out.

PS. I was again too curious so I pulled the pendulums out of my clocks. The first one that is like your pendulum --- no lead. The second one that is like yours --- full of lead with a domed top to fit inside the chrome tube. (so much for my flawless memory). The third one that is like Steve's --- no lead. All still running and keeping time (I do need to check the BPH with my microset now) I think we are barking up the wrong tree.

 

[ssohner]

I finally got arround to measuring the dimension from the bottom of the rate adjuster to the bottom of the pendulum. As illustrated in the pictures, the three lathe tools are a combined 1.875", the steel rule reads 5 11/32" (5.344"), and according to my feeler gage the pendulum is 0.011" from the bottom of the case. All that comes to 7.208'" which converts to 183.08 mm.

So I am way off the mark compared to Carl's clocks. I must have the wrong movement in the right case or the right movement in the wrong case. The only way I know of to make any further determination is to count the gears in the time train, which means dissasembling again. I wish I had documented that when I had the chance.

 

[Carl Bergquist]

The pictures show what I measured, basically 7 1/2". The bottom edge of the adjuster is the pivot point of the pendulum it does not move. No matter how high or low you set the upper part only lengthens or shortens the pendulum. So all three of my clocks keep time using 7 1/2" with about 1/4 inch to spare. The third picture shows that I have about 3/16" clearance and you will note that I have lots of room for adjustment. The balsa is 1/8 inch square. Looking at your picture I can not see that your adjuster is any different. It should not matter how long your pendulum leader and suspension spring is cause that would be corrected for by the adjuster. Someone else might know the answer to this. Could a strong suspension spring possibly lower the actual pivot point of the pendulum so as cause your problem? I have messed with this clock so I doubt that it is keeping time where you see the pendulum right now, but it did. I just have to get my Microset back out and set the BPH.

 

[Fitzclan]

A thicker feather will speed up your clock as will a shorter one. This is where you should be focusing. The only thing you can’t change is the amount of space between the hanger and bottom of case. Your clock has more than likely had the suspension changed at least once over the years. It may be too thick and is also the only measurement that Carl has failed to mention. A thinner feather will buy you the space you need without fiddling with all the other stuff. Been there, done that.
Good luck.

 

[ssohner]

Evernia and Fitzclan both suggested early on that the feather on the suspension rod might be too thick or not long enough. I can't make mine longer but I might be able to make it thinner. It might be worth a try to see what I can do with some emery cloth.

If I order from Timesavers I have to buy a dozen.

Thanks everyone for all the feedback.