We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back to
the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of xx:00,
several minutes later. The clock only ever stops at night - ie 00:57 rather
than 12:57. It also only does this every few days, not every night. During
the day it runs perfectly.

Is it plausible that a fault (eg a damaged/dirty tooth) on the hour-hand
gear which revolves once every 12 hours could cause the clock to stop, given
the very low gearing and hence torque-multiplication between the
pendulum/escapement gear and the hour-hand gear? Could such a fault
reproducibly stop the clock at 12:57 (with no latitude either side) And
could this only affect the clock at night (eg when the house has started to
cool down)?

Presumably the peg that initiates the chiming mechanism exerts a slight
back-pressure on the gear train. Is it likely that this back-pressure would
be greatest for one hour-chime than another - ie is it significant that it's
after the longest chime (12 bells for 00:00/12:00) and before the shortest
(1 bell for 01:00 or 13:00)? Or is that a red herring?

It doesn't seem to happen more often when the clock's mainspring is less
fully wound.

The clock repairer will sort it out, but I'm curious about the physics of
it?

On 08/04/2021 13:59, NY wrote:
We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back
to the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of
xx:00, several minutes later. The clock only ever stops at night - ie
00:57 rather than 12:57. It also only does this every few days, not
every night. During the day it runs perfectly.

Is it plausible that a fault (eg a damaged/dirty tooth) on the hour-hand
gear which revolves once every 12 hours could cause the clock to stop,
given the very low gearing and hence torque-multiplication between the
pendulum/escapement gear and the hour-hand gear? Could such a fault
reproducibly stop the clock at 12:57 (with no latitude either side) And
could this only affect the clock at night (eg when the house has started
to cool down)?

Presumably the peg that initiates the chiming mechanism exerts a slight
back-pressure on the gear train. Is it likely that this back-pressure
would be greatest for one hour-chime than another - ie is it significant
that it's after the longest chime (12 bells for 00:00/12:00) and before
the shortest (1 bell for 01:00 or 13:00)? Or is that a red herring?

It doesn't seem to happen more often when the clock's mainspring is less
fully wound.

The clock repairer will sort it out, but I'm curious about the physics
of it?

Firstly, do you mean the strike (counting out the hours) rather than the
chime (The quarter hour bongs)?

I suspect that the problem will lie with the date advance at midnight;
the hour hand rotates twice in 24 hours, but there is another wheel
geared down at 2:1 to advance the date. I suspect that the spigot
that advances the date wheel is riding onto the surface of the date
wheel instead of pushing it along.

May I suggest that you join the clocksgroup in groups.io?

Often those marginal things are hard to pin down since trying to get a look
at what is doing it often makes it work flawlessly!

I had a sideboard clock like you suggest, This always stopped at the same
time, but if you jacked it up one side to about the height of a cassette
tape it ran all day. I don't have it any more!

Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"NY" wrote in message
...
We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back to
the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of xx:00,
several minutes later. The clock only ever stops at night - ie 00:57
rather than 12:57. It also only does this every few days, not every night.
During the day it runs perfectly.

Is it plausible that a fault (eg a damaged/dirty tooth) on the hour-hand
gear which revolves once every 12 hours could cause the clock to stop,
given the very low gearing and hence torque-multiplication between the
pendulum/escapement gear and the hour-hand gear? Could such a fault
reproducibly stop the clock at 12:57 (with no latitude either side) And
could this only affect the clock at night (eg when the house has started
to cool down)?

Presumably the peg that initiates the chiming mechanism exerts a slight
back-pressure on the gear train. Is it likely that this back-pressure
would be greatest for one hour-chime than another - ie is it significant
that it's after the longest chime (12 bells for 00:00/12:00) and before
the shortest (1 bell for 01:00 or 13:00)? Or is that a red herring?

It doesn't seem to happen more often when the clock's mainspring is less
fully wound.

The clock repairer will sort it out, but I'm curious about the physics of
it?

gareth evans wrote:

I suspect that the problem will lie with the date advance at
midnight; the hour hand rotates twice in 24 hours, but there is
another wheel geared down at 2:1 to advance the date.

Do we even know whether this clock tells the date?

On 08/04/2021 13:59, NY wrote:
We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back
to the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of
xx:00, several minutes later. The clock only ever stops at night - ie
00:57 rather than 12:57. It also only does this every few days, not
every night. During the day it runs perfectly.

Do you recall Shell Beach as well? :-)

https://en.wikipedia.org/wiki/Dark_City_(1998_film)


--
Adrian C

"gareth evans" wrote in message
...
On 08/04/2021 13:59, NY wrote:
We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back
to the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of
xx:00, several minutes later. The clock only ever stops at night - ie
00:57 rather than 12:57. It also only does this every few days, not
every night. During the day it runs perfectly.

Firstly, do you mean the strike (counting out the hours) rather than the
chime (The quarter hour bongs)?

I suspect that the problem will lie with the date advance at midnight;
the hour hand rotates twice in 24 hours, but there is another wheel
geared down at 2:1 to advance the date. I suspect that the spigot
that advances the date wheel is riding onto the surface of the date
wheel instead of pushing it along.

The clock does not have a date display.

It has two chiming mechanisms: the Westminster chimes every quarter hour and
the striking on the hour. When I said "the hour-chiming mechanism kicks in
at an indicated time of xx:00", I meant that start of the chiming sequence.
The bongs follow a few seconds later after the chimes have finished. Without
a seconds hand I can't say how accurately the start of the chiming sequence
or the start of the striking correlates to the xx:00:00, but I think the
minute hand is pretty close to the 12 position. I imagine that's one of
those things which a clock repairer adjusts. He'd probably need to remove
the hands to remove the face so he could get access to the front face of the
mechanism. Given the cost of the repair, it may have been a complete
dismantle, clean and reassemble, maybe even with re-turning some of the
shafts and fitting correspondingly smaller bearings - but that's all
supposition.


Anyway, it's not date advance because there is no date dial. Do date advance
dials move continuously as the day progresses, or do they move suddenly from
20 to 21 etc at midnight? From your description of "geared down by 2:1" I
presume it's the former.


At least the clock hasn't started chiming 13 so I won't be finding a
Midnight Garden anywhere - and anyway, my name's not Tom ;-)

On 08/04/2021 13:59, NY wrote:
We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back
to the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of
xx:00, several minutes later. The clock only ever stops at night - ie
00:57 rather than 12:57. It also only does this every few days, not
every night. During the day it runs perfectly.

To determine the number of strikes there is usually a "snail cam"
(stepped), and there is a lever which drops onto it just before the hour
- you may be able to hear it. (The sound is known in horological circles
as the "warning".) Perhaps the lever that drops is incorrectly adjusted
so it fouls on the cam - it will be at its highest for 12 strikes. I
suggest you watch the mechanism carefully. There's no reason why there
should be any difference between 12 noon and midnight.

--
Max Demian

On 08/04/2021 21:46, NY wrote:

At least the clock hasn't started chiming 13 so I won't be finding a
Midnight Garden anywhere - and anyway, my name's not Tom ;-)

Or Earl of Bridgewater but his did it at 1pm for end of lunch break.

http://www.est1761.org/out-and-about/worsley

The canal in Worsley itself is an interesting orange rust colour from
the mine drainage even today or at least it was last time I looked.

--
Regards,
Martin Brown

On Thu, 8 Apr 2021 13:59:02 +0100, "NY" wrote:


We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back to
the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of xx:00,
several minutes later. The clock only ever stops at night - ie 00:57 rather
than 12:57. It also only does this every few days, not every night. During
the day it runs perfectly.

Is it plausible that a fault (eg a damaged/dirty tooth) on the hour-hand
gear which revolves once every 12 hours could cause the clock to stop, given
the very low gearing and hence torque-multiplication between the
pendulum/escapement gear and the hour-hand gear? Could such a fault
reproducibly stop the clock at 12:57 (with no latitude either side) And
could this only affect the clock at night (eg when the house has started to
cool down)?

Presumably the peg that initiates the chiming mechanism exerts a slight
back-pressure on the gear train. Is it likely that this back-pressure would
be greatest for one hour-chime than another - ie is it significant that it's
after the longest chime (12 bells for 00:00/12:00) and before the shortest
(1 bell for 01:00 or 13:00)? Or is that a red herring?

It doesn't seem to happen more often when the clock's mainspring is less
fully wound.

The clock repairer will sort it out, but I'm curious about the physics of
it?


The greatest resistance is not necessarily allied to the most bongs.
There could be a snail-shaped cam in there which has its greatest
distance from the pivot at midnight. This would imply that the clock
knows the difference between night and day in order for the user to be
able to silence the chimes at night.
--
Dave W

On 08/04/2021 22:14, Martin Brown wrote:
On 08/04/2021 21:46, NY wrote:

At least the clock hasn't started chiming 13 so I won't be finding a
Midnight Garden anywhere - and anyway, my name's not Tom ;-)

Or Earl of Bridgewater but his did it at 1pm for end of lunch break.

http://www.est1761.org/out-and-about/worsley

The canal in Worsley itself is an interesting orange rust colour from
the mine drainage even today or at least it was last time I looked.

It definitely still is.

I was very surprised when I looked into the back of the clock I no longer
have to see that there were in fact no bells at all, just some loosely
coiled springs that rang at different notes, however it is indeed the case
that the device that cocked the chiming mechanism, operated by another
clockwork motor did in fact prepare itself very slowly by raising the
various hammer things a couple of minutes out, but that this raising and
lowering during the strikes was obviously faster, as it was, presumably
driven by the other clockwork mechanism. It all seemed very complicated to
me, but I suppose there are a lot of different designs due to history.
Brian

--

This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Dave W" wrote in message
...
On Thu, 8 Apr 2021 13:59:02 +0100, "NY" wrote:

We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back to
the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of xx:00,
several minutes later. The clock only ever stops at night - ie 00:57
rather
than 12:57. It also only does this every few days, not every night. During
the day it runs perfectly.

Is it plausible that a fault (eg a damaged/dirty tooth) on the hour-hand
gear which revolves once every 12 hours could cause the clock to stop,
given
the very low gearing and hence torque-multiplication between the
pendulum/escapement gear and the hour-hand gear? Could such a fault
reproducibly stop the clock at 12:57 (with no latitude either side) And
could this only affect the clock at night (eg when the house has started
to
cool down)?

Presumably the peg that initiates the chiming mechanism exerts a slight
back-pressure on the gear train. Is it likely that this back-pressure
would
be greatest for one hour-chime than another - ie is it significant that
it's
after the longest chime (12 bells for 00:00/12:00) and before the shortest
(1 bell for 01:00 or 13:00)? Or is that a red herring?

It doesn't seem to happen more often when the clock's mainspring is less
fully wound.

The clock repairer will sort it out, but I'm curious about the physics of
it?

The greatest resistance is not necessarily allied to the most bongs.
There could be a snail-shaped cam in there which has its greatest
distance from the pivot at midnight. This would imply that the clock
knows the difference between night and day in order for the user to be
able to silence the chimes at night.
--
Dave W

On 08/04/2021 22:54, Dave W wrote:
On Thu, 8 Apr 2021 13:59:02 +0100, "NY" wrote:

We have a (clockwork) chiming clock. A few months ago it was cleaned and
re-fettled by a clock restorer (previously it didn't go at all). After
several months, it has begun stopping. Clearly it will need to go back to
the repairer.

But the exact symptoms are intriguing. I've noticed it always stops at
12.57. The hour-chiming mechanism kicks in at an indicated time of xx:00,
several minutes later. The clock only ever stops at night - ie 00:57 rather
than 12:57. It also only does this every few days, not every night. During
the day it runs perfectly.

Is it plausible that a fault (eg a damaged/dirty tooth) on the hour-hand
gear which revolves once every 12 hours could cause the clock to stop, given
the very low gearing and hence torque-multiplication between the
pendulum/escapement gear and the hour-hand gear? Could such a fault
reproducibly stop the clock at 12:57 (with no latitude either side) And
could this only affect the clock at night (eg when the house has started to
cool down)?

Presumably the peg that initiates the chiming mechanism exerts a slight
back-pressure on the gear train. Is it likely that this back-pressure would
be greatest for one hour-chime than another - ie is it significant that it's
after the longest chime (12 bells for 00:00/12:00) and before the shortest
(1 bell for 01:00 or 13:00)? Or is that a red herring?

It doesn't seem to happen more often when the clock's mainspring is less
fully wound.

The clock repairer will sort it out, but I'm curious about the physics of
it?

The greatest resistance is not necessarily allied to the most bongs.
There could be a snail-shaped cam in there which has its greatest
distance from the pivot at midnight. This would imply that the clock
knows the difference between night and day in order for the user to be
able to silence the chimes at night.

Its colder at night typically


--
"Anyone who believes that the laws of physics are mere social
conventions is invited to try transgressing those conventions from the
windows of my apartment. (I live on the twenty-first floor.) "

Alan Sokal