The English "Half-chronometer"

J.W. Benson "Observatory" watch made by Tavannes and
described  as a "Half-chronometer" as was the English made
Benson "Field" watch and many others.

The English description of a watch as being a "Half-chronometer" is, perhaps, a rather grandiose name for what the Americans termed an "adjusted" watch meaning a watch adjusted for temperature as explained in this Wikipedia entry.

This does not mean that other watches will not cope adequately with changes in temperature but that the "Adjusted" or "Half-chronometer" watch has been rigorously tested at extremes of temperature and adjusted to minimise errors.

Unfortunately most good quality English watches, particularly those by Benson, Rotherham and other good makers in Coventry and London plus most imported from Switzerland before the late 1930s and signed by English resellers are not marked "adjusted" so it is only possible to establish if they are by tracking down contemporary adverts such as the following.

From a J.W. Benson Sales catalogue from the late 1930s.

A Rare Rotherham and a bit about hairspings & balances.

A Size 12 Rotherham for Hoefler &
Co of Devenport. 19 Jewels, 1901.

This is at first sight a normal high end size 12 Rotherham with 19 jewels but two things make it unusual, first is still has an original watch paper in the back as described in my last post, but more important is the very rare balance assembly.

Normally these movements have a cut compensating balance with a normal steel Breguet hairspring, however in the late 1890's a new alloy known as "Elenvar" was devised by Charles Édouard Guillaume (who got the 1920 Nobel prize for physics for the development), its key property was that unlike steel its flexibility (modulus of elasticity) did not change with temperature. When used as a hairspring it removed the need for a compensating balance.

A very rare solid balance with an
Elenvar Breguet hairspring.

Most companies implemented the Elenvar hairspring with a screwed balance which allowed the balance to be balanced fairly quickly (as a car wheel with a new tyre) and the weight and number of screws could be used to adjust the moment of inertia to match the hairspring to make the watch run too time. 
 
With this movement Rotherham tried a different route and used a traditional 3 armed solid balance which is probably gold. Balancing and tuning was done by removing slight amounts of material from the balance as can be seen from the picture to the right..

This is the only watch I have seen with this arrangement and it is likely that Rotherham only made a few, probably because the amount of skilled work required to set up the balance would more than likely have made it more expensive than the normally sprung cut compensating balance.

Dating Pocket Watches.

Revised and extended December 2016 from the original post August 2015

Dating watches can be a problem but here are a few ways that it is done.

American Watches

A Waltham 1892-Vanguard dated
to 1902 by the serial number, but
probably re-cased (see below).

These are generally the easiest as for many makes, such as Waltham and Hamilton, production records are still extant and enthusiasts in the US have put a huge amount of effort into putting them into online databases so by taking the serial number of the movement (not the case number!) and entering it you can get the production date usually to within a year or possibly two but sometimes to within a month.

Details of the type of watch may also be provided although there are some errors largely due to mixed production runs (e.g. lever and pendant set, etc..) and the occasional transcription error. The original Waltham database is maintained by the NAWCC but the most comprehensive site I have found is The Pocket Watch database.

Swiss Watches

Are more problematic, of the makes I regularly deal with, Omega have published the dates that each million watches were produced so by interpellation the production date can be determined within a year or two. Dates are known for Zenith and some for Longines, & Baume.

A Cyma movement with the serial
number under the dial

For most of the other makes the data is not generally available or, as is the case with Revue Thomman, the movements do not carry a meaningful serial number, just a 2 or 3 digit number to identify watches within a batch of production.

Having had a lot of watches by Cyma and Tavannes I have been able to build up a good database of serial numbers vs date for production between c1930 and 1938 using the silver hallmarks (see below) which is now good enough to identify the date to within a year. See this post for details.

Beyond this is comes down to experience and identifying key features such as machine set jewels which determines the earliest possible date.

English Watches.

An LWC movement showing the
serial number under the dial
dated to 1897.

Are very difficult, as far as I know production records are only available for the Lancashire Watch Company and those that are not accessible.

Other makes (assuming you can identify the maker!) are difficult as several companies appear to have multiple number sequences, indeed occasionally an Errington will turn up with two serial numbers one from each major sequence.

Generally it is therefore necessary to reply on silver case hallmarks or when in a filled or rolled gold case to compare with previous dated examples which may not be as reliable.

Silver Cases.

Silver hallmarks for 1903 by the
Birmingham Assay. The movement
is a Waltham 1899-620 also 1903.

English silver and gold case hallmarks are unique in having a date year, although until 1974 this is not quite in line with the calendar year and varied by Assay house with the Birmingham "year" starting in July and the London "year" in May, normally I refer to just the starting year, so Birmingham 1908 would indicate that the case was assayed between July 1908 and June 1909.

Some Swiss watches have only the Swiss hallmarks but others have English import marks.

For older English watches this is generally a reliable method of dating but with the introduction of the standard watch case we start to have problems due to recent re-casing of orphaned movements into orphaned cases, a problem which appears to be getting worse judging from what I see on eBay.

A subsequent post here will look at  how to identify re-cased watches. See also J.W. Benson movements in Dennison cases.

Does non-functional Geneva gear matter?

This post was prompted by my restoration of three watches by Rotherham of Coventry (an unusual number to have in at one time!) two of which had fully functional Geneva stop gear whilst the other was missing part of the device.

As explained in some detail in this previous post Geneva Stop gear is designed to limit the maximum and minimum pressure from the mainspring to help control isochronism (varying time keeping as the watch runs down).  But quite frequently the "nib" on the central portion is broken or the other section is missing altogether. This is, I suspect, normally down to previous repairers letting down the mainspring too fast which is easily done. It may also have just worn out, broken as a result of some other fault or been removed to give the watch a longer run time.

A modern
Mainspring

So does it matter that it is broken? Well the answer, as is frequently the case, is yes and no.

Yes it matters because the watch is not complete, so I always discount them a little. And yes if a contemporary mainspring was used it would most probably have a noticeable impact on time keeping.

But thing have changed in the way that mainsprings are manufactured; in the 1800's and into the twentieth century mainsprings were made equally thick through out their length so that as they unwound the pressure from the still wound coils delivered unequal pressure over the period.

A modern mainspring on the other hand  is made so that the strength varies along its length to reduce variation in pressure. This significantly mitigates the problem so that on a 120 year old watch the affect on timekeeping is unlikely to be significant or noticeable without close monitoring.

Cleaning watch movements.

Face plate of a movement by the
Lancashire Watch Co before cleaning

I was recently asked on Facebook how I cleaned the particularly dirty watch movement shown, that reply whilst covering the essentials was necessarily brief so here is the full story.

The obvious thing to do and the recommendation of most books on watch maintenance for the amateur, is to use metal polish and indeed this in combination with other techniques will work and can be a quick way of getting the top plate of a movement clean and shiny [see this later post for an example], however there are some significant disadvantages firstly it is purely a cosmetic exercise not getting into the nooks and crannies of the watch or helping with the cleaning of the critical moving parts and secondly there is a real risk or removing the gilding from a gilt movement or the often very thin nickel or other coating frequently found on Swiss watches. The better method is not cheap as it requires the purchase of special cleaning and rinsing fluids and an ultrasonic cleaner cleaner.

The fluids are designed to allow the cleaning of “complete movements” as it says on the label. I do not think this is a good idea for old pocket watches, particularly those with motor barrels that can not be removed without taking the movement to pieces, as the fluid will interact with the oil in the barrel making it ineffective and judging from a few movements I have had in that have been done this way and from my experience with leaving too much oil on the movement before cleaning, it is likely to cause bad staining of the movement as the mixture spreads over the watch. In any case if the movement is to be cleaned properly then it needs to be taken to pieces so its best to do that up front.

This is the way I do it:

 

The same LWC movement after cleaning

 1. The movement is first broken down into its major parts, the top plate being removed together with the train, escapement and motor barrel. I leave the winding and setting gear in place if it is fixed in as the components are too small to easily handle. The mainspring is removed from the barrel.

2. Any obvious oil on the plates, barrel etc. is removed with tissue or a cloth, then loose material removed with a tooth brush with some mentholated spirits if necessary to get rid of thickened oil and other significant deposits. 

3. Everything goes into the cleaner for 10 minutes. Whilst ultrasonic cleaning is a relatively gentle process it does lighten gilding a little, particularly on very old watches, and it is best not to over do it, a really dirty piece might get and extra five minutes but no more. 

4. Pieces are then put into a rinsing fluid to get rid of the solvents and to chemically remove any water that might be present. After patting dry with tissue and blow drying the hairspring they are left to dry before the next stage. 

At this point it is worth mentioning one additional cleaning problem that may have to addressed. Sellers of old watches, on eBay in particular, are eager to be able to describe them as “working” or “ticking” so are liable to soak them in oil (lengthening part 2 of the cleaning process) to get them moving and occasionally spraying the whole movement with WD40 or similar. The later process will undoubtedly cause the hairspring to get coated in oil, the former will only probably do so. This will mean that although the watch may tick the coils of the hairspring will stick together and if the watch runs for more than a few seconds it will typically run  fast and erratically. The same effect may happen naturally over a very long period through corrosion or leakage of oil from the barrel. In both cases it is unlikely that the ultrasonic cleaning will be enough and it will be necessary to resort to some very strong solvents to clean up the hairspring.  

5. Some of the winding gear may be removed for inspection at this stage and, particularly on some English keyless movements, to allow easier reassembly of the movement.

And the top plate of the same.

6. As the movement is put back together everything gets a final hand cleaning with a toothbrush which should remove any lingering pieces of crud and in particular fluff and hairs which frequently get wound up in the wheels. Smoothing broaches, peg wood and other implements are also used to make sure jewels, pivot holes etc. are clean. This is also the time to visually check that everything is complete, undamaged and the correct shape.

7. After reassembly the movement is wound and immediately put onto the escapement analyser to make sure that the new mainspring is not over strong which among other things threatens to break the impulse jewel if the balance wheel turns by more than 360 degrees.

Some watches may run well immediately and can be given an initial regulation, using the analyser, and adjustments to get it into beat and to reduce any positional errors, others will take their time to get going but all need to run for 24 hours before going on the analyser again. If I am fortunate that will be the movement done, if not it could mean a lot of work making repairs, fiddling with the hairspring, etc.

The Riddle of the Hands (with appologies to Erskine Childers)

Rotherham key wound and set
full plate watch, Coventry, 1903.

This post is prompted by another query as to why a watch with gold main hands has a blue second hand, Carruthers  may have been able to find an answer but I can't and nor can others I have asked.

Swiss watches with gold hands normally have all three gold whereas most English watches such as this Rotherham, which was made in the year that Riddle of the Sands was published, does not.

The same will be found on English cased Waltham watches as most found in the UK are. Plain, rather than filigree,  gold hands were I am told rare in America and do not appear in my copy of the Waltham parts catalogue, so it is likely that hands were sourced and fitted locally conforming to English practice, which fits with a common method of selling these watches as described in my post on the standard watch case.

I think it will remain one of life's little mysteries.

Hunter, Half-Hunter or Open Faced?

The choice between the three types of watch is one that should be made for aesthetic reasons, not because of any perception that the Hunter type is more robust, in fact in some ways it is not. This post explores why and gives some of the pro's and con's of the different types.

First what are they?

• The Hunter has a solid one piece cover or lid over the "crystal" and watch dial, normally by pressing the crown the cover should pop open by itself - if you don't get your thumb in the way of the hinge!
• The Half Hunter (a.k.a. Demi Hunter, very occasionally a "Napoleon" and referred to by the Lancashire Watch Company and presumably by others as a "Sight Hunter")  also has the cover but there is a small window in it so that the time can be read reasonably well without opening the lid, the hour hand should be distinguishable from the minute hand when looking at it through the window, this is usually achieved by having two large swells on it - see the picture below.
• The Open Faced watch just has the "crystal" which normally was glass. Later various types of plastic was used, which often changed a nasty yellow or green colour over time. A modern replacement will usually be acrylic and looks much like a glass one, it is essentially unbreakable and makes an open faced watch perfectly strong enough for normal use. Acrylic is more susceptible to scratching but a replacement costs only a few pounds (plus fitting). 

A Waltham "Hunter"

The Hunter is so named because with a lid covering the glass it was more suitable to wear when riding a horse (to hounds - hence it is known as a "Hunter") than an open faced watch as there was always the chance of being thrown against the pommel of the saddle and crushing the watch. This was a significant issue when, before about the mid 19th century, watches  had a hugely domed "bulls eye" glass front, it became less of an issue however when the glass became significantly flatter and was less susceptible to damage. A secondary advantage was that the front cover protected the glass from being scratched although the front window of a half hunter was at least as susceptible.

 Advantages:

• They can look good and there is a certain ceremony, which many people enjoy, of taking out the watch and popping it open to tell the time.
• The crystal is protected from scratching.

Disadvantages:

• You have to open it to tell the time and if worn in the breast pocket of a jacket (how I normally wear mine when wearing a Tweed jacket without a waistcoat) that is not easy.
• They are rarer, particularly silver ones, and to many are more desirable and so are more expensive than an open faced watch.
• The hinge for the front lid is vulnerable to wear and to accidently being bent or in severe cases torn off.
• The springs that open them can break and replacing them, particularly on English watches, can be problematical, however replacements for "standard" watch cases, particularly those by Dennison can usually be found.

An English Half Hunter by
J.W. Benson

The Half Hunter is in my view preferable to the Hunter:

Advantages:

• The time can be read without opening them which is more convenient.
• They look very good.

Disadvantages:

• As for the Hunter except as mentioned above.
• They are much sought after and so are more expensive again than the Hunter.

Watches as a financial investment? Not recomended!

Rotherham 19J Keyless 1907

I have been asked several times recently for advice on watches as an investment so I thought it might be useful to post one of my replies here:

I do not advise buying functioning, serviced watches as a financial investment. Yes the price of watches is going up and I suspect that the rate of increase will increase, given the current shortage of supply particularly of  good English three-quarter plates and other high grade watches.

Update, October 2016: Watches are now in even shorter supply and prices of unrestored watches have definitely risen very significantly and continue to do so!

 

The problem is if you are buying from me or some other dealers you are buying a serviced  / restored watch with a guarantee, when you come to sell it will be without either. For a cheaper watch the cost of a full (not just an "oil") service will be a significant part of the value of the watch so a dealer will not be able to offer a lot for it and even on a more expensive watch he will have to factor in the cost of a service, a risk premium in case there is a hidden problem with the watch, overheads and a profit margin. 

 

If you sell at auction it will probably sell at well below the current retail selling price for essentially the same reasons and will attract fees and in many cases a buyers premium of 20% which will further depress the price.

 

Buy for utility, to preserve for future generations and to enjoy, not for short term financial gain - but you might be lucky in the long term. 

Why the Blank Faces?

Have you ever wondered why so many pocket watches do not have a makers or retailers name on the face? Well wonder no more.   

A Waltham 1899-620 with a bespoke 3 piece dial by Fattorini
the name was incorporated into the dial during manufacture
an expensive option and not common. This is from 1903, later
the Waltham name would probably have been included or a
Waltham dial used with the Fattorini name applied later.

In England (but not normally in America) it was the custom for the retailer, not the maker, to sign a watch, probably harking back to when watches were finished locally. The maker might sign the watch under the dial (e.g. Rotherham) or not at all (most others), an analysis I carried out of watches from three important Coventry makers showed 70% were not overtly signed by the maker. Most Swiss makers conformed to this custom at least into the 1930s although they may have had their own "English" brand, such as Revue signing their movements "Vertex".

American makers almost always signed there movements and faces (despite the dials being sourced in UK for from Switzerland) although a retailer might then add their name with a transfer print or commission their own dial as did Fattorini in the example shown here.

Names were applied to watch faces in two main ways, the expensive and best method was to have the name applied along with the numbers, chapter ring etc. during the manufacture of the ceramic face, this meant the name would be permanent but this was really only practical for relatively high volumes or for expensive watches and brands.

LWC watch for Fattorini

Alternatively the name could be painted on or more likely applied by a transfer print process which was much cheaper. The problem is that these are non-permanent solutions and the name would flake off and when it got too bad the owner or restorer would remove the rest.   

That is probably what happened to this recently restored watch by The Lancashire Watch Company for Fattorini & Sons, dating from 1911, although the movement is not signed the silver case has the Fattorini hallmarks so we can be sure that it was one of “their” watches and it would surely have had their name on the face.