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Clocks keeping time

binman

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Nov 16, 2011
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Hi, what would you consider as being normal, for the lose or gain for any clock after a month running.assuming it had been adjusted pretty fine at the beginning.
 

svenedin

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A bit of "how long is a piece of string" question!

It depends on many factors. Firstly, how old the clock is. Very early clocks are generally terrible timekeepers. As clock making moved on there were refinements that improved timekeeping e.g. the fusee for spring driven clocks and various types of compensated balances in carriage clocks. Timekeeping also improved with developments in escapement design and temperature compensation in weight driven clocks.

The second consideration is the quality of the clock. Clearly a cheaply made mantel clock is never going to match the timekeeping of a precision regulator.

Thirdly the condition the clocks is in. It is unlikely that a poorly maintained or badly worn clock will match the timekeeping it had when new.

So the answer is it depends......

PS As a rule of thumb I don't object to a couple of minutes a WEEK for a carriage clock or most mantel clocks. I would expect about the same for a longcase unless it had a temperature compensated pendulum. My most accurate longcase regulator gains about 2 minutes in 6 MONTHS.
 

Kevin W.

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A weight driven clock is usually more accurate.
 

svenedin

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A weight driven clock is usually more accurate.
Often they are but once again it depends what you are comparing. A cheap weight driven clock will not necessarily be more accurate than a well made English spring driven fusee for instance. The reason that weight driven clocks tend to be more accurate is that the power is more constant.

On a side-note I have considerably improved the accuracy of my older longcase clocks by replacing the original pendulum rod with one made of Invar. It is cheating of course, because Invar was not invented when the clocks were made.
 
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Kevin W.

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A 8 day ogee or a 8 day grandfather clock keep good time, if properly cared for. My grandfather clock does not loose any noticeable time, and a i have a 8 day box clock which may loose a minute or less in a month.
But compared to say a astromical regulator well we all know it cant match that, but who has one.:)
 

svenedin

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A 8 day ogee or a 8 day grandfather clock keep good time, if properly cared for. My grandfather clock does not loose any noticeable time, and a i have a 8 day box clock which may loose a minute or less in a month.
But compared to say a astromical regulator well we all know it cant match that, but who has one.:)
A nice English longcase with mercury compensated pendulum is what you need. I have one of those, about 1880/1890.....My father bought it in 1960 for what he thought was a song (£1,000) but actually it cost more than a car. I am told that he has made more than 20X his investment but he will never know. He died in 1980 when I was 8 years old after a holiday in the USA where he caught Legionnaires Disease from air conditioning. Terrible time, 1980, I was only 8 years old. I was there too, LA and San Francisco. I recently (this year) went back to LA but instead of flying we drove from sea to shining sea......
 
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nicksey

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Nov 12, 2009
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svenedin, I am so sorry to hear about your sad loss when you were so young. You must have inherited your love of clocks from your father.

You have probably posted pictures of your English longcase before, but could you add some here as I would love to see it
 

eskmill

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Binman's query, "Clocks keeping time" does not apply to clocks and watches. Only musicians keep time. Clocks and watches maintain a rate of so many oscillations per minute, hour, day, week, month etc.

The best keep a constant rate. The ideal is to regulate a timepiece so that at the conclusion of a series of regular intervals ie: a day, week or month, the timepiece indicates that its rate is either plus or minus a noted number of seconds, or minutes at the end of the measurement period.

Attempts to regulate a mechanical timepiece so that it compares precisely with a criterion is a "fool's errand." Far better to regulate the timepiece so that its rate, either gaining or loosing is constant.

A well regulated timepiece is one that needs to have its minute hand moved part of one minute on the 30th day of the month.
 

Scottie-TX

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Apr 6, 2004
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For me and almost entirely weight drivens I shoot for a fraction of minute a week and consider that acceptable. So for my monthrunners, two to three mins. per mo. are my goal.
 

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