Enfield weight-driven deadbeat keeps stopping

Peter Planapo

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Hi all,

My 1930s deadbeat Enfield was running very nicely but for the last couple of months has been randomly stopping, and now it's every day or two.

When this happens, and if I then try to move the minute hand forward, there's resistance. Obviously I don't force it, which I'm sure would damage something. I can, however, freely move the minute hand backward slightly (1 minute is enough) and then it will easily go forward past the point it had stuck at.

The symptom suggests to me that one of the pallets may be meeting an escape tooth on its tip, which would stop the clock I think. A possible fix might be to drop the verge a hair.

Am I on the right track?

Many thanks
Peter

P.s. I've just found and downloaded Mike Dempsey's monograph on the deadbeat, and will know more about them when I've read it.
 

Isaac

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Hi all,

My 1930s deadbeat Enfield was running very nicely but for the last couple of months has been randomly stopping, and now it's every day or two.

When this happens, and if I then try to move the minute hand forward, there's resistance. Obviously I don't force it, which I'm sure would damage something. I can, however, freely move the minute hand backward slightly (1 minute is enough) and then it will easily go forward past the point it had stuck at.

The symptom suggests to me that one of the pallets may be meeting an escape tooth on its tip, which would stop the clock I think. A possible fix might be to drop the verge a hair.

Am I on the right track?

Many thanks
Peter

P.s. I've just found and downloaded Mike Dempsey's monograph on the deadbeat, and will know more about them when I've read it.
Sounds to me like there's wear in the movement, which will need to be addressed. If it's a triple train chime clock, then either the chime/strike train might be binding up the time train and stopping the clock from running.
 

Kevin W.

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Pictures would really help alot. I am having trouble trying to guess what this movement could be.
 

Peter Planapo

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Sounds to me like there's wear in the movement, which will need to be addressed. If it's a triple train chime clock, then either the chime/strike train might be binding up the time train and stopping the clock from running.
I'll pull the mvt tomorrow and check for wear. I don't remember anything significant, but I haven't stripped it. Yes it's a triple train but it never stops on a quarter or half, always some random place. Last time it was on ten past.

Pictures would really help a lot. I am having trouble trying to guess what this movement could be.
Roger that, pics tomorrow.
 

shutterbug

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If the stop pin is in the way as the lever rises, it will sometimes stop the clock. Usually it will just be pushed aside by the lever, but in the perfect position it won't. Check that. Easy to fix if it's the problem.
 

chrisuk

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I've had the same effect from time to time. Sometimes the easiest adjustment is to move the cam which locks the chime at the end of run round a bit on its shaft so that the warning pin is well away from the lever. Only a tiny movement is needed, too much and you may have to adjust both the chime locking plate (the one that has the four lobes of different lengths, one for each quarter) and the gear that drives the chime barrel.
 

Peter Planapo

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Some photos
1. The clock as purchased in the auction rooms
2.Today with dial off and door open
3. Front plate
4. Warning mechanism
5. Escapement
6. Mvt mounted on bench, running on crutch
7. Warning mechanism showing stop pin and lever
8. Front plate close up, can't see cannon wheel but it's there and fine.

I unfortunately knocked the minute hand backwards during dismounting, so the jam was cleared and I can't now see what was stuck. I was surprised the chiming mechansim could stop the clock, actually, as there are separate mechanisms only connected to each other through the cannon wheel, lift and lever. The minute hand was stuck going forwards very rigidly, with no softness or give, until it was touched backwards a bit and freed. But I held the lever down as the minute hand approached warning, and the clock did indeed stop.

If the stop pin is in the way as the lever rises, it will sometimes stop the clock. Usually it will just be pushed aside by the lever, but in the perfect position it won't. Check that. Easy to fix if it's the problem.
The stop pin is being prevented from moving by the lever, until the lever is lifted by the cannon wheel, and then off it goes into warning, but I don't see any way the stop pin could prevent the lever from moving.

I've had the same effect from time to time. Sometimes the easiest adjustment is to move the cam which locks the chime at the end of run round a bit on its shaft so that the warning pin is well away from the lever. Only a tiny movement is needed, too much and you may have to adjust both the chime locking plate (the one that has the four lobes of different lengths, one for each quarter) and the gear that drives the chime barrel.
Do you mean by the cam the small disc with a segment cut out of it, shown in my pic no 4? And are you saying that the stop pin shouldn't be touching the lever? This stop pin is touching.

BTW the moveement has no signs of wear. It's 90 years old, I don't think it was run very much. It hasn't been re-bushed.

And now I have it on the bench running at 10x speed without the pendulum, it's sometimes going right past the quarters without chiming. Sometimes it sets off the warning and then no chimes, sometimes there's no warning at all. That certainly does "chime" with the idea there's someting up with the warning mechanism.

It's a bit of a head-scratcher (for me).

Peter

View attachment 608344 Enfield auction august 19.jpg 20200827_171051 (Medium).jpg 20200827_171021 (Medium).jpg 20200827_172842 (Medium).jpg 20200827_172901 (Medium).jpg 20200827_173146 (Medium).jpg 20200827_173822 (Medium).jpg 20200827_174155 (Medium).jpg
 

Kevin W.

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I would start with a baseline first. The movement is dirty. Dismantle clean and do some bushing and polishing first. Then you have some idea after inspection and testing.
 

Peter Planapo

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I would start with a baseline first. The movement is dirty. Dismantle clean and do some bushing and polishing first. Then you have some idea after inspection and testing.
Thanks for the suggestion Kevin, Yes that's always a good plan with any clock but this one is a lot cleaner than you think (harsh lighting for the photo exaggerates what dust and dirt there is) and I'm pretty sure it doesn't need bushing. It's far from being that kind of basket case for which a full overhaul is unavoidable. I wish I had time to strip and overhaul every clock I have but it's a 2-day job and for various reasons I haven't time (or even a proper workshop) at the moment. Tinkering on my desk or on the kitchen worktop are OK till I get back to normal. Cheers!
 

Simon Holt

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Now that you have it out and on a test stand, you can run it until it stops and try to see what has jammed. But you'll need to test it with the pendulum on because otherwise it's not a real test.

Incidentally, I have what looks like the exact same clock and had always thought it was 1950-1960. How did you date yours?

Simon
 

Peter Planapo

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Now that you have it out and on a test stand, you can run it until it stops and try to see what has jammed. But you'll need to test it with the pendulum on because otherwise it's not a real test.

Incidentally, I have what looks like the exact same clock and had always thought it was 1950-1960. How did you date yours?

Simon
I have no way to get an accurate date, but the design is classic art deco, and the simple marking "Enfield" shows it's pre-1950, when the Enfield name was no longer used by Smiths (who bought the Enfield Clock Co in 1933). I think too that after 1939 the clocks were called Smiths-Enfield; thus Enfield alone denotes pre-1939.

Yup, you're right, a real test has to be in real conditions. But that means having at least a 4ft test stand (the seconds pendulum is over 1m long), whereas I was testing it clamped to the desk. Perhaps I'll cobble up a 60cm pendulum for testing at a level I can usefully work at.
 
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