Lorenz Furtwangler Sohne: Escapement? Opinion Needed!

[MuensterMann]

I have a tall-case clock was made by Lorenz Furtwängler Söhne, in Furtwangen, Germany in the Late 1920s. I cannot keep it running. The movement was cleaned part by part and freshly lubricated. The bushings were not bad, just some slight wear. However, I could not keep it running for more than a few hours. I decided to bush the bushings that I though were not bad. Still, cannot keep it running. The pendulum is a very heavy one. Everything seems to be in order, so I am thinking that perhaps it is the escapement not set properly. It does give a loud tic toc and the balance (even tic toc) is 0 to 1% and consistent. I just posted a video of the escapement in action on YouTube. I need expert opinion and advice!!!

 

[bruce linde]

if that were mine, i would decrease the amount of lock... the EW teeth should (i think) just hit the locking faces (and just clear the impulse faces)... otherwise you're introducing additional friction. looks to me like too much sliding of teeth across locking faces... which i see as friction. curious as to what others have to offer.

 

[bruce linde]

p.s.: you didn't mention whether you had tried a different suspension spring (or details about the one being used) and/or whether you made sure there was sufficient slop in the crutch slot (or whether you'd polished the sides of the crutch slot and the crutch pin, etc.)).

 

[MuensterMann]

Thanks Bruce. The suspension spring is new. The broken one had a thick metal housing to fit in the slit. I found a similar sized spring (but not exact) in my drawer. The housing was not as thick as that old one that broke, so I put some filler metal around it to give it a snug fit in the slot. Perhaps I don't have a suitable spring?

I did not polish the crutch sides or pin. I will do that now.

 

[bruce linde]

i always do the crutch pin and crutch slot sides, because why not?

make sure there's no slop where the suspension spring is held in the suspension block... it can move somewhat (maybe slightly more resistance than when turning a minute hand) but doesn't want to be loose. the crutch slot wants a little bit of slop, but not too much. no red flags go up when i see the suspension spring pictured.

good luck!

 

[Willie X]

The escapement isn't perfect but it's working OK.

What's the story on that pendulum? The movement does not appear to be designed for a "very heavy" pendulum.

A very heavy pendulum escapement will not be moving through nearly that much of an angle.

Have you ever seen this clock run with this pendulum?

Willie X

 

[shutterbug]

The video is not very focused, but I can't see any impulse face on the pallets. Upside down maybe, or maybe just not in focus. But initially I agree with Bruce that you have a lot of lock. Can you post a good pic of the pallets?

 

[Willie X]

Slo-mo is good too, or move the leader slowly back and forth by hand. A view, more in line with the arbor, would also help, if possible. Willie X

 

[MuensterMann]

Here is another video with more illumination and hopefully better focus.

 

[Dick Feldman]

For as long as you have been at this clock repair thing, you should, by now, understand escapements.
If not, you should have at least a rudimentary understanding of how they work.
Do yourself a favor and read: This Old Clock by David S. Goodman.
Your local library should have or can get a copy for free. It can also be purchased on eBay or Amazon for not too much money.
That is how I feel,
Dick

 

[MuensterMann]

The overall pendulum weighs 6.8 pounds; it is about 115cm from end to end; and the heavy bob is about 22cm in diameter. It seems to be original to the clock.

 

[Willie X]

How much pendulum swing? From the video, there is going to be a wide pendulum swing?

Also, are the little screws for the adjustable pallet bits buggered up?

Do you have good, completely free, end shake on the pallet arbor?

OK, three question limit reached ...

Willie X

 

[MuensterMann]

A photo of the pallets is below. The pallets are tight - no slop or movement - the screws are holding them well and no buggered up. The pallet surfaces do not show any wear at all. The arbor has normal play (end shake).

There have been times when the clock will run for days. Then I think all is well - so I put on the dial, and then back to an hour or two. There is something going on and perhaps it is on the borderline of some resistance that is fluctuating. That is why I was hoping that someone would notice something in the verge.

 

[RickNB]

I have only been studying clocks for a few years, but form what I have learned here are some things that stand out for me.

First, as others have said, there seems to be an excessive amount of lock in the escapement for this kind of deadbeat. That means there is excessive friction and that could be the cause of the movement running out of gas.

On the back plate, the two posts that restrict the movement of the pendulum seems to be bent away from the centre. I have not seen this before - all the ones I have seen are perpendicular to the back plate. It's as if someone wanted to create space for a wider swing of the pendulum, which clearly is not what not how this clock was designed.

It strikes me that there is also an excessive amount of drop. I think that if the pallet nibs were properly adjusted there would be less lock and less drop as well.

 

[Dick Feldman]

The performance of that escapement depends on ample power in the train.
It cannot, will not, perform without sufficient power.
Any loss of power will exhibit itself as an ill adjusted escapement.
The result often times is labeled as the cause.
Experience tells me that dead beat escapements suffer greatly from low power, especially in the verge pivots.
Those escapements do not normally suffer from wear, or do they magically become out of adjustment.
Some German made movements do not have a lot of excess power and the judgement on how much (power robbing) pivot movement allowed should be of utmost importance.
Your symptoms are of a lack of power in the movement train and the escapement is probably the victim rather than the cause.
JMHO,
Dick

 

[MuensterMann]

Sigh. There are only 4 wheels in the time train from power wheel to escape wheel. They spin so smoothly unloaded! Now with new bushings in there, I would think that when loaded it should be smooth as well. The lifting lever does not add much resistance - and the clock never stops during the lift. I just took the 4 wheels off the front of the clock that drive the hands to make sure there was not any added friction here. I did a little more polishing just in case. All is smooth.

Well, there are two weights that seem to be original - just like the rest of the clock. One is about 7 pounds, the other about 12 pounds. For giggles, I just switched the 12 pound from the strike to the time. Let's see how this combination works.

 

[POWERSTROKE]

check the verge pivots. Sometimes they look ok but have just enough slop to cause problems.

 

[JimmyOz]

You have a 6.8 pounds pendulum being driven by a 7 pound weight?
I think your swap is a good idea.

 

[bruce linde]

You have a 6.8 pounds pendulum being driven by a 7 pound weight?
I think your swap is a good idea.

my strasser & rohde regulators (one original, one repro... both with 12 pound pendulums) run with four pound weights... compounded.

tight bushings, not enough end shake, bent pivots, depthing issues, suspension spring, crutch too tight, not in beat, EW teeth, pallet angles, weight pulleys or dry mainsprings... pick your poison.

 

[Vernon]

It looks like that there is a glob of solder on the verge arbor. From my limited experience, that connection should be a friction fit for adjustment of the beat (at least on German R&A's) not sure with your clock. Make certain that there is no looseness in that area as it could stop your clock.

Vernon

 

[MuensterMann]

"Well, there are two weights that seem to be original - just like the rest of the clock. One is about 7 pounds, the other about 12 pounds. For giggles, I just switched the 12 pound from the strike to the time. Let's see how this combination works."

Interestingly enough the clock has been running with the 12 pound weight on the time side. The strike has enough with 7 pounds.

 

[shutterbug]

That's logical. It takes less power to run a strike train. Many Hermle's have a lighter weight on the strike than on the time. However, 5 pounds is a lot of difference.

 

[Dick Feldman]

Needing a heavier weight to drive the time train does not seem logical.
If you are able to make the train operate with more weight, that is an indication of low power in the time train.
You indicated that you had bushed the "necessary" places in the movement.
Adding additional weight is normally shunned as a repair method.
It only takes one marginal pivot hole to cause train power loss and you may have one or more that you have not attended to. Two marginal pivot holes will increase the chance of unreliable operation.
German made movements sometimes do not have a lot of excess power.
JMHO,
Dick

 

[MuensterMann]

I agree with DF. I tried it and it worked, but I was skeptical, because sometimes even with the lighter weight the are periods of no go, and go. I think it may be borderline or there is something intermittent based on position of something or both.

I took off the pendulum to adjust the length (had to check the regulation screw). After I put it back on, it stopped after an hour. I adjusted the tick tock to 0% and tried again - stop after an hour.

I keep thinking that it has to be the escapement. The one bushing holding the verge is a little sloppy. Could it be that that bushing needs attention? Perhaps I must adjust those pallets a little to optimize the transfer of energy.

 

[Willie X]

Running a clock like this, without a pendulum with a beat amp on it, can be an eye opener. Use a lighter weight and mark the mesh points when it stops Willie X

 

[Dick Feldman]

Then again, it may be both the escapement and a lack of power.
Either may make the clock unreliable and both can make the clock unreliable.
I am not trying to be a smart aleck.
Best,
Dick

 

[POWERSTROKE]

I keep thinking that it has to be the escapement. The one bushing holding the verge is a little sloppy. Could it be that that bushing needs attention? Perhaps I must adjust those pallets a little to optimize the transfer of energy.

I repaired a Hubert Herr 1 day movement about 3-4 years ago. It took many bushings. Ran but was finicky to stay in beat. Took it apart again. Looked at the verge bushings. They looked fine. Maybe an infinitesimal amount of play. I bushed them, because I became tired of the erratic beat, and would sometimes stop if it tilted ever so slightly. That clock runs like a champ for the past 3.5 years.

 

[MuensterMann]

Yes, I would think if the beat were erratic, I would look at the verge bushings and well as the escapement wheel. This clock I can get in beat to 0-1% and it stays firmly in beat from then on.

There is a blob of solder on the verge - and not sure why. The anchor is firm on that arbor, although I am able to move it with a little force to get it to a good even beat area. I wonder if that slight movement there is stealing power. I am not sure I can get that solidly fixed.

 

[Willie X]

Those pallet bits look mighty narrow. Do they fit snuggly the groove in the pallet body? Wider pallets would give you longer impulse and less lock. They could have been swapped, or the pallet assembly could be a replacement. Only way to know for sure would be to survey another like movement. Willie X

 

[MuensterMann]

Unfortunately I am still dealing with this clock not running. The time side didn't need serious bushing repair, but out of curiosity I bushed them. The time train moved so smoothly! But, no improvement. I did try the heavier weight on the time side, and it initially worked. I then wound it for week 2 and it would not go anymore. I just now disconnected the front gears that drive the hands. No improvement. I reached into the gears and jiggled (shake) a few of the high ones, and it started to work - but only for a few hours, then none after that. So, I took off the pendulum and the escapement does move back and forth - with weight on. It has been running for more than a day in this mode - as I was curious to see if perhaps it would stop which would indicate that perhaps even thou the train moved so smoothly without weight, I thought perhaps it was the weight that would be causing the resistance. However, after a day they is no apparent jamming happening.

As for using the heavy weight on the time side, it doesn't make sense from the standpoint that the strike is usually heavier. On the other hand, maybe the heavy pendulum requires it - like a Hermle movement needing extra weight for the larger pendulum bob sizes.

The pallets seem to be a normal fit for the escapement wheel. Are there any examples of this movement out there?

Geez. There are only 4 wheels involved in the time train. The front time gears are disconnected. The strike lift has no resistance. I would hate to surrender.

 

[Willie X]

Never give up ...

If the power transmission is smooth over time (use a very light weight) and the slow roll test. Stop and start the escape wheel dozens of times over, (what would normally be) several days running time. If this checks out, it's your escapement. The drops should be small and equal and the locking should be small but positively and obviously there, for every tooth.

You don't have to sit and stare, do the beat amp thing, already mentioned. An out of place sound is often more noticeable than a visual would be. Turn it up loud and go about your other work.

That last video shows a lot of overswing, for a clock that won't run. Was the pendulum being overswung?

Hopefully I'm not repeating to much,
Willie X

 

[MuensterMann]

The startup of the pendulum before the video may have been over-swung.

 

[MuensterMann]

Willie, I would like to try to the test (tests) that you suggested, but I don't have a full understanding of them. Could you provide a little more info? Thanks!

 

[MuensterMann]

Are we talking about 2 separate tests? Do you mean put a lower weight on it, but heavy enough to keep the tic tocking without pendulum? Then stop the escape wheel with finger, then let go, and the test is if the tic tocking continues or it stops? Is this the slow roll test??

 

[Willie X]

For the slow roll test you would remove the pallet arbor. It's to see if the power will transfer through the train, consistently, at an extremely low power level. It's not a quick test. You could have a single bent tooth, or bad depthing, on the first or second wheel.

The fast roll test, with the normal weight and no pallet arbor, will allow you to see and hear defects in the train as it turns very fast, probably a few 100 times normal speed. Bent arbors, pinions, and wheels will become obvious, along with bad noises you would not normally notice.

Willie X

 

[TEACLOCKS]

Your Pictures and Videos Lousy.

 

[tracerjack]

Your Pictures and Videos Lousy.

Pictures seemed fine to me. Video could have been in better focus, but you could still see the pallets and where the teeth landed on the pallet.

 

[shutterbug]

Try posting another video of the EW and pallets after they have run awhile and the swing has settled into its normal pattern.

 

[MuensterMann]

Here is another video after the clock was running for one day - so no over-swing. This is the best video I can get with my available cameras to see this escapement action. In this case it was taken with an iPhone.

 

[Vernon]

I'm seeing a tiny amount of over swing and no recoil. If the lock is minimal, probably nothing wrong with the escapement.
Vernon

 

[MuensterMann]

The clock is still running in steady-state as shown in the video. The tic toc is balanced and I am using the smaller weight and only have the 4 time chain wheels connected. I know if I mess with it, then it will stop.

So, the escapement action looks good?

 

[Vernon]

I think so, perhaps now check your bushing work. Did you bush the verge that you mentioned was sloppy? Do what Willie suggest in post 35. You could also put the wheels in pairs between the plates and spin them as they should gradually glide to a stop. Check that there is end shake. You didn't seemed convinced that the verge might not slip where the solder is so you might check that again.
Vernon

 

[shutterbug]

There might be too much lock, but it depends on where the impulse face starts, which I can't see in the video. You need lock, but just a little.

 

[Ralph]

You need a better camera.

IMHO, Ralph

 

[tracerjack]

Most of my 400 day are deadbeats. Yes, the video is blurry, but from what I can see, the locks looks fine. If it is still fussy, I agree with shutterbug to go a little less lock. If it is running well, I’d leave it alone.