WatchUSeek Watch Forums banner

1 - 20 of 24 Posts

·
Registered
Joined
·
689 Posts
Discussion Starter · #1 ·
I often see in literatures the term "pocket chronometer". But I do not see much description regarding these highly sought after pieces. What is pocket chronometer exactly?

With railroad standard of the yesteryears or modern day COSC, there are certain accuracy standard to meet, isochronism, position timing .. etc. Is it the same way with pocket chronometers?

I see many are English in origin, so I am assuming in the early 1800s the English lever escapement was used. The escapement teeth were known to be extreme prone to damages and if made earlier, verge escapement were the standard ... which were even worst time keepers.

I am very interested to learn a bit more about these curiosities.
 

·
Registered
Joined
·
1,558 Posts
Well, I'll get the ball rolling. "Chronometer" was originally a generic term applied to any type of watch regardless of timekeeping accuracy. Similarly, "chronoscope" was the generic term for a watch used to measure short periods of time, ie, stopwatch. When the first timing tests were conducted by astronomical observatories, they applied the term "observatory chronometer" to indicate those that passed. This was following the precedent of marine chronometers, which also had to pass testing. Many manufacturers used the "chronometer" label to infer a quality that wasn't earned! It wasn't until COSC patented the term "chronometer" in 1973 that the word took on the meaning we understand today. I'm really quite ignorant of the English pieces but Radger's recent thread has been very enlightening.
 

·
Registered
Joined
·
689 Posts
Discussion Starter · #3 ·
Thanks for the insight.

Interesting, this puzzling question came exactly from astronomical events. My local NAWCC meeting this week. We were watching presentation regarding the passing of Venus and the timing instrument used for these events the past 400 years. Many scientist used multiple clocks and pocket chronometer if they were in remote locations. Hence my question.

One of the instrument they used was the "chronodrometer". I am assuming they are similar to the "chronoscope" you are referring to. Measuring only the passing period of time.

If no common standard was used for these pocket chronometers, how would one identify a true pocket chronometer from standard pieces?
 

·
Registered
Joined
·
689 Posts
Discussion Starter · #5 ·
Thanks, learned alot by reading up on spring detent escapement

Pocket chronometers with detent escapement

A compensated balance = bimetallic balance (notice how the two layers of metal used in the balance)



A spring detent escapement.





But would a bimetallic balance and spring detent escapement really be all that accurate vs say a railroad standard watch?

A compensated balance.
A spring detent escapement.
 

·
Registered
Joined
·
3,383 Posts
Thanks, learned alot by reading up on spring detent escapement


A spring detent escapement.
Here is my take on the use of the term 'chronometer'

Nowadays the term chronometer seems to apply any accurate watch, usualy adjusted to position.

In the distant past, the term chronometer was used for a specific type of super accurate timepiece
used by ships as a navigation aid. For 150 years until the advent of quartz accuracy these chronometers
used the detent escapement of which there are two main types, the spring detent and the pivoted detent.

The detent escapement, because it was used in ships chronometers was termed the 'chronometer escapement'
and so for many years when the term 'chronometer' was used for a time piece it was expected to have the chronometer
escapement.
A pocket chronometer, until the late 19thC, would have a detent escapement and the reasons as to why these are
predominantly English are many.
The UK was, at these times, the predominant maritime nation accounting for a large percentage of the worlds shipping,
and solving the 'longitude problem' was upermost in the early history of English horology. The best clock and watchmakers
were producing chronometers for maritime use and so they would use their skills to produce pocket versions for selected
clients, rich ship owners perhaps.

In the accounts of Usher & Cole of 1870 a marine chronometer of best quality with rate, cost £21.00.
A pocket chronometer in 18c gold case cost £35.00
A Geneva watch from the same price list in 18c gold with gold dial and dome was £4.10s

The cost to produce these early pocket chronometers and subsequent high price is why they are rare, the reason
why they are English is because the best English watchmakers, drawing on their heritage, were competent
to produce them.
English chronometers used the spring detent escapement as used in marine chronometers. The detent escapement
that you illustrate with your link is a later early French/Swiss? 20thC pivoted detent.

The bottom illustration is a spring detent chronometer escapement.

Anyways, as technology progressed and other escapements besides the 'chronometer escapement' became increasingly
more accurate, they were entered for testing to prove that they could pass the testing that a 'chronometer' passed and
so these to were called chronometers and assured a customer that his watch was supremely accurate.


But would a bimetallic balance and spring detent escapement really be all that accurate vs say a railroad standard watch?
It would be an unfair competition, the chronometer escapement is the most detached escapement of any and the most accurate.
Even with an early bi-metalic balance with its inherent mid temp errors, a quality chronometer escapement of the spring detent type would
beat a railroad watch for accuracy hands down.
 

·
Registered
Joined
·
689 Posts
Discussion Starter · #8 ·
Thank you, Radger. For all the wonderful information.

I was aware of the fact that English clock and watchmakers were at those times, the best in the world. The Swiss were in a sense, the Timex of its days. Making inexpensive pieces for the common folks.

Sort of related to the pricing information you provided. According to book I am currently reading, an average grade jeweled Waltham pocket watch movement in 1890 was $10.89. (At those time movements were paired with cases at the jobber/ jeweler, so unfortunately, we could not compare it with your 1870s data.) But by 1899. The average grade Waltham movement has plummeted to just $4.49. Thanks to industrialization and automation of machineries. Waltham produced not only cheaper watches overall. But more accurate and precise timepieces on a mass scale.

So an English marine chronometer of the best quality for £21.00, actually sounds very reasonable.

My understanding is that detent escapement has some inherent problem. For one, they are none self starting. Besides that, if they are such good time keepers. I wonder why we do not see them being used more frequently? Expect for a few marketing gimmickry escapements or low cost pin levers, the short swiss lever escapement practically dominate the market after the 1900s. Even if pricing was a concern, if the detent escapement is so much better, I am certain more makers would have adopted this system. Why didn't they?











Here is my take on the use of the term 'chronometer'

Nowadays the term chronometer seems to apply any accurate watch, usualy adjusted to position.

In the distant past, the term chronometer was used for a specific type of super accurate timepiece
used by ships as a navigation aid. For 150 years until the advent of quartz accuracy these chronometers
used the detent escapement of which there are two main types, the spring detent and the pivoted detent.

The detent escapement, because it was used in ships chronometers was termed the 'chronometer escapement'
and so for many years when the term 'chronometer' was used for a time piece it was expected to have the chronometer
escapement.
A pocket chronometer, until the late 19thC, would have a detent escapement and the reasons as to why these are
predominantly English are many.
The UK was, at these times, the predominant maritime nation accounting for a large percentage of the worlds shipping,
and solving the 'longitude problem' was upermost in the early history of English horology. The best clock and watchmakers
were producing chronometers for maritime use and so they would use their skills to produce pocket versions for selected
clients, rich ship owners perhaps.

In the accounts of Usher & Cole of 1870 a marine chronometer of best quality with rate, cost £21.00.
A pocket chronometer in 18c gold case cost £35.00
A Geneva watch from the same price list in 18c gold with gold dial and dome was £4.10s

The cost to produce these early pocket chronometers and subsequent high price is why they are rare, the reason
why they are English is because the best English watchmakers, drawing on their heritage, were competent
to produce them.
English chronometers used the spring detent escapement as used in marine chronometers. The detent escapement
that you illustrate with your link is a later early French/Swiss? 20thC pivoted detent.

The bottom illustration is a spring detent chronometer escapement.

Anyways, as technology progressed and other escapements besides the 'chronometer escapement' became increasingly
more accurate, they were entered for testing to prove that they could pass the testing that a 'chronometer' passed and
so these to were called chronometers and assured a customer that his watch was supremely accurate.




It would be an unfair competition, the chronometer escapement is the most detached escapement of any and the most accurate.
Even with an early bi-metalic balance with its inherent mid temp errors, a quality chronometer escapement of the spring detent type would
beat a railroad watch for accuracy hands down.
 

·
Registered
Joined
·
3,383 Posts
Thank you, Radger. For all the wonderful information.

I was aware of the fact that English clock and watchmakers were at those times, the best in the world. The Swiss were in a sense, the Timex of its days. Making inexpensive pieces for the common folks.
The Swiss produced their share of high grade watches mid 19thC but they couldn't produce a hairspring good enough for chronometer
accuracy. If a Swiss maker wanted to produce a very accurate watch then he had to source a hairspring from the UK and, as you can imagine,
he would have a job getting hold of the very best.

Sort of related to the pricing information you provided. According to book I am currently reading, an average grade jeweled Waltham pocket watch movement in 1890 was $10.89. (At those time movements were paired with cases at the jobber/ jeweler, so unfortunately, we could not compare it with your 1870s data.) But by 1899. The average grade Waltham movement has plummeted to just $4.49. Thanks to industrialization and automation of machineries. Waltham produced not only cheaper watches overall. But more accurate and precise timepieces on a mass scale.

So an English marine chronometer of the best quality for £21.00, actually sounds very reasonable.
That's interesting pricing info for the Walthams, strangely enough I was trying to find cost new of
a high grade Waltham from 1870 but no joy.

£21.00 for a Marine chronometer might sound reasonable, but £35.00 for a pocket version!!! I'll bet
that was a lot of money in 1870...in fact if I spend that kind of money on a watch today, then it
better be good.


My understanding is that detent escapement has some inherent problem. For one, they are none self starting. Besides that, if they are such good time keepers. I wonder why we do not see them being used more frequently? Expect for a few marketing gimmickry escapements or low cost pin levers, the short swiss lever escapement practically dominate the market after the 1900s. Even if pricing was a concern, if the detent escapement is so much better, I am certain more makers would have adopted this system. Why didn't they?
I think that if they had been cheaper we would definately see a lot more pocket chronometers despite their inherent problems.

As you say, they are not self starting and are also liable to 'set' (stop) if subjected to a sudden rotational force at the
wrong time. As Trim says they had to be used carefully, you could get away them in a pocket watch but no chance in
a wrist watch.
It is an escapement that was always very labour intensive to produce and required high skills.
It wasn't until the 20thC, that the U.S Hamilton managed to introduce machine process to the making of
marine chronometers with any success.
 

·
Registered
Joined
·
3,383 Posts
Hi radger,



Even this problem was solved like in this movement:



Here the compensation was linearized by splitting the usable temperature range into
four sections. Further details here:


Regards, Roland Ranfft
Wierd and wonderful looking balance on your watch Roland, that is the first three
armed balance wheel I've ever seen on a detent chronometer of any type, marvelous ingenuity.
Does your watch still have its case?
 

·
Registered
Joined
·
2,504 Posts
I just wanted to comment on a couple of statements:

By araton: "an average grade jeweled Waltham pocket watch movement in 1890 was $10.89... ...but by 1899. The average grade Waltham movement has plummeted to just $4.49"
All Waltham watches were jeweled. In this 1889 catalog it can be seen that prices varies from $7 for a 7j Broadway to $70 for a Crescent Street (movement only). In a 1903 an advertisement we can see a spread from $9 to $100.
Although many more lower grade watches were made you can't compare an average price of produced watches (where did you get that figure?) with a specific chronometer watch.

By Radger: "strangely enough I was trying to find cost new of a high grade Waltham from 1870 but no joy".
I have in front of me a re-print of a Waltham advertisement from 1870. The new for the year Crescent Street was offered at $50. If you go to 1872, an American grade would have been higher in price.
 

·
Registered
Joined
·
4,037 Posts
Hi radger,

Wierd and wonderful looking balance on your watch Roland, that is the first three
armed balance wheel I've ever seen on a detent chronometer of any type, marvelous ingenuity.
Does your watch still have its case?
Yes, it is still complete, except the end of the hours hand:




I suspect it was intended as marine chronometer by several reasons:
1) A winding hole in the back asks for a pair case, but the short pendant would
make this difficult. More probably it was placed into a box.
2) The case is fagile and shows signs of extensive usage, while the bow is
not accordingly worn. It appears it was well used, but never on a chain.
3) The banking screws on the balance, adjusted to different temperatures
lead to temperature dependent position errors. Allthough small, and moreover
minimized by using three arms instead of two, only running the watch generally
face up or even in a cardanic suspension would give best performance.

Another pic shows the cylindrical hairspring with end curves on both ends:



All in all an item designed for high precision outside a pocket, although still
usable as accurate pocket watch after some 200 years.

Regards, Roland Ranfft
 

·
Registered
Joined
·
18,169 Posts
Great thread! Thanks folks. Very informative.
 

·
Registered
Joined
·
689 Posts
Discussion Starter · #15 ·
Hi Erik

The data in question came from "Moore, Timing A Century, Table 11, Sales and Prices, 1890-1905, Waltham Watch Company," p. 87

Here is a quick run down

Year Average Price
1890 $10.09
1891 $9.86
1892 $7.28
1893 missing
1894 $5.10
1895 $5.01
1896 $4.84
1897 $4.80
1898 $5.12
1899 $4.49

I am not certain how the author came about the data. But I am assuming that he included more then 18 size movements. After all. American Watch Co of Waltham was the largest US maker that had a full line up. In fact, if I am not mistaken, they were the first to came up with the concept of product line. Waltham's Model 1857 was finished in a variety of grades to reach the maximum amount of prospective buyers using the same watch design and tooling. (Home Watch co grade, Broadway, Watson grade, Bartlett grade and Appleton and Tracy grade were all variation of the same 1857 design.)


I just wanted to comment on a couple of statements:

By araton: "an average grade jeweled Waltham pocket watch movement in 1890 was $10.89... ...but by 1899. The average grade Waltham movement has plummeted to just $4.49"
All Waltham watches were jeweled. In this 1889 catalog it can be seen that prices varies from $7 for a 7j Broadway to $70 for a Crescent Street (movement only). In a 1903 an advertisement we can see a spread from $9 to $100.
Although many more lower grade watches were made you can't compare an average price of produced watches (where did you get that figure?) with a specific chronometer watch.
 

·
Registered
Joined
·
6 Posts
Great thread! Thanks folks. Very informative.
I'm curious, what would the wage of a skilled tradesman have been in the mid-1800's in England?

I suspect 35GBP would be several week's wages for the average worker... probably like a $5000 watch is now. Even the Walthams, at $10 to $100, were a week or more wages for the typical working person.

A fascinating history lesson, nevertheless.
 

·
Registered
Joined
·
2,504 Posts
Hi Erik

The data in question came from "Moore, Timing A Century, Table 11, Sales and Prices, 1890-1905, Waltham Watch Company," p. 87

Here is a quick run down

Year Average Price
1890 $10.09
1891 $9.86
1892 $7.28
1893 missing
1894 $5.10
1895 $5.01
1896 $4.84
1897 $4.80
1898 $5.12
1899 $4.49

I am not certain how the author came about the data. But I am assuming that he included more then 18 size movements.
Let's not derail this thread by focusing on Waltham prices, but just a last comment: The prices you quote might have been wholesale of a high volume low cost 7j model. Taking the 1896 example of $4.84, it does not reflect the retail prices in this 1896 advertisement ranging from $8 to $60 for three different sizes.
 

·
Registered
Joined
·
18,169 Posts
I'm curious, what would the wage of a skilled tradesman have been in the mid-1800's in England?

I suspect 35GBP would be several week's wages for the average worker... probably like a $5000 watch is now. Even the Walthams, at $10 to $100, were a week or more wages for the typical working person.

A fascinating history lesson, nevertheless.
There are sites that give this information. $10 to $100 was more monthly than weekly wages... Working people carried Ingersols, not Walthams (unless their employer was a railroad).
 

·
Registered
Joined
·
3,383 Posts
Hi radger,



Yes, it is still complete, except the end of the hours hand:

I suspect it was intended as marine chronometer by several reasons:
1) A winding hole in the back asks for a pair case, but the short pendant would
make this difficult. More probably it was placed into a box.
2) The case is fagile and shows signs of extensive usage, while the bow is
not accordingly worn. It appears it was well used, but never on a chain.
3) The banking screws on the balance, adjusted to different temperatures
lead to temperature dependent position errors. Allthough small, and moreover
minimized by using three arms instead of two, only running the watch generally
face up or even in a cardanic suspension would give best performance.

Another pic shows the cylindrical hairspring with end curves on both ends:

All in all an item designed for high precision outside a pocket, although still
usable as accurate pocket watch after some 200 years.

Regards, Roland Ranfft
Great to see that your watch still has a case.

I suspect you are correct that this watch once had a box.
I have seen a silver cased pocket chronometer in a fitted mahogany box,
it's use was as a scientific instrument for expeditionary navigation or other.

I think if your watch was originaly made and intended for pocket use, it would
likely have been in a gold case.
 

·
Registered
Joined
·
8,842 Posts
Detent escapements have two problems that make them less than perfect for mobile watches:

1) They are not self-starting, but more importantly,
2) They do not lock.

With a detent there is no positive mechanism to prevent the detent from releasing the escapement tooth uncommanded. This makes them very susceptible to gain large amount of time if frequently jarred.

As to pocket chronometers, there are many examples of these and even a marine chronometer design or two that use the lever escapement. One of the more notable is the Hamilton Grade 22.

For marine chronometers, one feature that is always present, is that stem set is not used, unless there is a lock-out mechanism. (same for railroad grade)

But would a bimetallic balance and spring detent escapement really be all that accurate vs say a railroad standard watch?
It would be an unfair competition, the chronometer escapement is the most detached escapement of any and the most accurate.
Even with an early bi-metalic balance with its inherent mid temp errors, a quality chronometer escapement of the spring detent type would
beat a railroad watch for accuracy hands down.
Maybe not hands down...

As accuracy was never the primary consideration, stability of rate was primary. In fact, quartz chronometers for the US Navy were allowed +/- 2 s/d in daily rate, which is something a Hamilton Model 22 could achieve. Requirements of rate variation due to temperature, isochromism and general irregularities of beat were, however, much tighter, and many have been out side the capabilities of some lever escapement movements.
 
1 - 20 of 24 Posts
Top