A 451-050H Strange Beat Rate - Request for Ideas

[Reuven Gruber]

I have a movement A 451-050 H. 114cm/60 which has recently been dissembled, cleaned and lubricated.

The clock needed to be regulated since it was not running at the correct rate

The clock is level and in beat. I set up the microset using the optical sensor and adjusted the pendulum to a rate of 3600 beats per hour

Came back the next day and the clock had lost around 3 minutes. I rechecked the rate and it was still 3600

What's going on!!

 

[ChimeTime]

In my less than professional ammeteur opinion, the 114cm/60 is a number that simply gets you close enough to begin tuning the clock. It is not an exact answer for all users. This because the gravitational pull on pendulums varies by locale. Additionally, a 114cm pendulum works out to be 56.03 beats per minute, not 60.

It's simply time to start increasing the beat rate in small increments.

Hope this helps.

 

[Willie X]

114 cm will have a cross reference number, sometimes two different cross reference numbers. This number will be out to three decimal places, that's your beat rate.

I just go by the hands ... they always speak the truth and any quartz clock or watch, with a second hand, will serve as a reference.

Willie X

 

[shutterbug]

I agree. Set it to run faster, check, repeat as needed.

 

[MARK A. BUTTERWORTH]

First, the beat rate on a Hermle movement marked 114cm should be exactly 3600 bph to keep proper time. That is true on a mountain or in DeathValley. It is the length of the pendulum that needs adjusted for altitude Due to the fact that the value of g will vary by altitude.
Second, the fact that it is losing time at that rate indicates to me that the hands are slipping due to insufficient tension on the washer over the minute arbor. If there were no tension, the pendulum could bet at 3600 bph and the hand not move at all. I believe the hands are simply slipping Especially when it goes into its quarter chime warning.

 

[John P]

I have recently rebuilt a Hermle 451-050H (114) with exactly the same issue. Losing time with beat set at 3600.
I ran the clock for 2 weeks here in the shop, creeping up and up until it kept up with our master clock Go figure!
Like Willie said, the minute hand has the last say on every clock.

 

[R. Croswell]

I have recently rebuilt a Hermle 451-050H (114) with exactly the same issue. Losing time with beat set at 3600.
I ran the clock for 2 weeks here in the shop, creeping up and up until it kept up with our master clock Go figure!
Like Willie said, the minute hand has the last say on every clock.

If the gear ratios of the going train require a beat of 3600 and you got it to keeping time by working the rate up to something more than 3600, then I'm afraid you are just compensating for the problem, not correcting the problem. When whatever is slipping starts to slip a bit more, you will have to keep increasing the beat to "keep up" until you run out of adjustment range, or it totally fails.

RC

 

[shutterbug]

I guess a lot depends on how accurate the timer is. Most read a bit off if the beat is not right.

 

[Dick Feldman]

Here is my take on the subject:
BPH numbers come from calculations from the number of teeth on the wheels in the time train.
Like the discussion in "The Modern Clock" by Goodrich, those calculations do not consider or will ignore things like friction, air movement, gravity, etc. Theoretical pendulums, for instance have only one dimension, that being length. A theoretical pendulum, once started will swing forever. That is not how things operate in this world. Published BPH numbers are good in that they give a preliminary goal.
I believe the proper BPH for any clock is that one that makes the hands travel and be accurate. That value is best achieved by trial and error and adjustment over a period of time.
As a test, take the clock movement you are working on and record BPH as the clock goes into warn or while in the warn period. It will not be the consistent 3600 that you regulated the clock to. It may lag by a few beats or even a lot of beats for part of the cycle you are measuring. That lag may be greater if the time, chime and strike wheel trains are under stress from wear.
You were probably careful to regulate the movement while it was not laboring with chime/strike warning. The number calculated from that period will be a bit faster than the average over a long period. The number/BPH you are seeking is really an average of many BPH measurements over a time period.
If this were a perfect world and the clock movement had no outside forces, you could be comfortable with a number from a chart or book.
Sorry, we do not live in a perfect world.
That is what I think,
Dick

 

[R. Croswell]

Here is my take on the subject:
BPH numbers come from calculations from the number of teeth on the wheels in the time train.
Like the discussion in "The Modern Clock" by Goodrich, those calculations do not consider or will ignore things like friction, air movement, gravity, etc. Theoretical pendulums, for instance have only one dimension, that being length. A theoretical pendulum, once started will swing forever. That is not how things operate in this world. Published BPH numbers are good in that they give a preliminary goal.
I believe the proper BPH for any clock is that one that makes the hands travel and be accurate. That value is best achieved by trial and error and adjustment over a period of time.
As a test, take the clock movement you are working on and record BPH as the clock goes into warn or while in the warn period. It will not be the consistent 3600 that you regulated the clock to. It may lag by a few beats or even a lot of beats for part of the cycle you are measuring. That lag may be greater if the time, chime and strike wheel trains are under stress from wear.
You were probably careful to regulate the movement while it was not laboring with chime/strike warning. The number calculated from that period will be a bit faster than the average over a long period. The number/BPH you are seeking is really an average of many BPH measurements over a time period.
If this were a perfect world and the clock movement had no outside forces, you could be comfortable with a number from a chart or book.
Sorry, we do not live in a perfect world.
That is what I think,
Dick

Quite true that variable external factors can affect the instantaneous beat rate, especially if the clock isn’t running very strong. If the beat meter is a Microset, using the optical pickup is more accurate, then setting the device to “average” will average the the reading over a longer period of time so brief excursions from the standard rate are compensated for.

RC

 

[Reuven Gruber]

First, the beat rate on a Hermle movement marked 114cm should be exactly 3600 bph to keep proper time. That is true on a mountain or in DeathValley. It is the length of the pendulum that needs adjusted for altitude Due to the fact that the value of g will vary by altitude.
Second, the fact that it is losing time at that rate indicates to me that the hands are slipping due to insufficient tension on the washer over the minute arbor. If there were no tension, the pendulum could bet at 3600 bph and the hand not move at all. I believe the hands are simply slipping Especially when it goes into its quarter chime warning.

Mark
I think that yours is the answer. What's the best way to increase the friction? And - do I put any lubricant on the washer?

 

[MARK A. BUTTERWORTH]

Unfortunately, you will need to disassemble the movement. Remove the tension washer over the hand shaft, and bend the 3 lobes on the washer. Don’t push any harder than necessary on the washer to reinstall the e clip. No lubricant is needed.