This FAQ is intended to cover the basics of watches and movements themselves.
It is not a buyer's guide; nor will it tell you where to get the best deal on a Rado. Furthermore, it does not talk about many other important issues, such as how the watch industry works. There is a short discussion of watch brands and accuracy (mainly to dispell the belief that the two are strongly linked), but otherwise, it does not concentrate on any particular brand (other than as examples).
What is a mechanical watch?
What is the difference between a movement, ebauche, and caliber
What is a "hack" seconds feature?
What does "17 jewels" mean?
Why do they use synthetic ruby?
Are more jewels better?
What is shock protection?
What is the "T", "T‹25", and the lower-case Greek sigma on my dial mean?
What is a MecaQuartz?
What is an Accutron?
What do I need to do to keep a mechanical watch running for a lifetime?
Why should I get a mechanical watch when a quartz watch is so much cheaper and more accurate?
What's the difference between a "manual" and an "automatic"?
How does an automatic mechanism work?
Are the Seiko Kinetic / Autoquartz therefore automatics?
What is a watch winder, and do I need one?
What is the best watch made? Is it [insert brand here]?
How accurate can I expect an [insert brand here] to be?
What does "adjusted" vs. "unadjusted" vs. "regulated" mean?
What is a chronometer? What is a chronograph?
What is a Rattrapante?
What is a Flyback?
What is a Column-Wheel?
Are Column-Wheel chronographs better than other types?
What was the first automatic chronograph movement?
What is a complication?
What's a Reserve de Marche?
What's a Perpetual Calendar?
What's a Tourbillon?
What's a Repeater?
Should I be concerned about radium on a vintage watch dial? How about Tritium?
What's the difference between acrylic, mineral, and sapphire crystals?
How do I remove the scratches from an acrylic crystal?
If a watch is advertised as "18K", what does that mean?
What do PVD, CVD, or PE-CVD mean?
What does Gold-Filled mean?
What are some other materials used as watch cases?
How do I remove scratches from my watch?
The basic design of mechanical watches has not changed very much in the past fifty years. What has changed is the use of high technology and modern materials in the design and manufacture of watches. Even with the fusion of CAD/CAM, electrospark erosion in the manufacturing, and titanium nitride cases; the pinnacle of watchmaking is still an expression of elegance of design, attention-to-detail in finishing and assembly, and the art of hand-tweaking movements for optimum performance.
Many watch companies will purchase complete movements from a major supplier such as ETA or Lemania, engrave their company's name and other information onto them, and encase it with their own or even contractor-supplied cases. This practice can be up-front - where the company acknowledges that the movements are not of their own design or manufacture, or it can be hidden - where the watch company claims to use "in-house" movements when the movements are in no way designed or manufactured internally.
Some watch companies will purchase an ebauche from a major supplier, polish and decorate the parts (i.e. finish the parts), and assemble it with standard parts to create a higher quality-controlled movement than the stock ready-made movement.
Other companies purchase ebauches, finish them to a high standard, modify parts of the movement, and add custom components like an upgraded escapement assembly - to create what might be called a custom version of that movement, much like how Carroll Shelby, AMG, or BMW's "M" division re-engineer existing automobiles to produce something with higher performance and exclusiveness. Many times, the company will rename the caliber as its own to reflect the modifications and finishing of the movement vs. an unmodified stock movement.
There is often a debate on whether a particular company is being deceptive in renaming a movement based on an outside supplier as an in-house caliber. It should also be noted that the largest supplier of ebauches in Switzerland, ETA, can provide a wide variety of finishes on its products, from very raw parts to fully finished movements complete with Geneva stripes and other decoration. They even have a subsidiary, Soprod, that can perform custom finishing and even modifications to the basic movement. Therefore, there is by no means a single level of quality that one can ascribe to an ETA movement - there are basic versions all the way up to fully finished ones.
A. Lange & Sohne have produced a watch that stops the balance when the crown is pulled out and automatically moves the second hand to the "0" position - to help facilitate setting against an accurate time reference.
A lower-end movement from before 1970 would typically use 5 or 7 jewels; this end of the market has pretty much been taken over by quartz. Nowadays, most manual wind watches will have a standard complement of 17 jewels, which are:
.Without any jewels, the steel wheel pivots would very quickly grind away the bridge and plate material until the wheels came out of alignment, and the movement would crash to a halt. In the inexpensive watch of yesteryear, the pivot holes may have been provided with hardened metal bushings.
Ruby is significantly better than steel in handling the forces involved, wearing long, and providing a nice low friction surface suitable for both high-load as well as high-speed motion. With modern production methods, they are cheap (~$0.02 each). And they look nice.
Only those pieces of the movement which are between the mainspring and the escape wheel are candidates for jeweling, as these are the movement parts that experience the large forces or relatively high speeds of the mainspring or escapement. Other components, such as the motion works (i.e. hour and minute wheels), calendar mechanisms, and winding train are not under this constant stress, and thus arguably do not need jewels.
Automatic winding movements will add about 4-8 jewels to help most efficiently transfer the relatively small rotor forces into winding the mainspring. Another factor has to do with how the watch is constructed - especially for chronograph movements and perpetual calendars. Some chronograph movements used today (including the ETA 2894-2) are modular in construction - meaning that a plate containing the chronograph works is grafted onto a basic timekeeping movement. Since the original timekeeping movements were not always designed with this in mind, it becomes critical for the add-on module to add as little "drag" as possible - which may indicate use of jewels for their low friction properties.
BTW, one will occasionally encounter a quartz movement with jewels in it - they technically aren't really necessary because a quartz wheel train is not constantly under stress.
As a historical note, there was a "jewel craze" about 50 years ago, where manufacturers, under the belief that the public thought more was always better, came up with 75 or even 100 jewel movements. Most of these jewels were not functional in any way, and the results looked ludicrous to an informed eye.
Shock protection is usually only applied to the balance because the high speeds and regular motion they are designed for - this kind of design goal leads one to small, extremely hard pivots, with most of the weight concentrated at the rim of the balance. These factors combine to make for a lot of broken pivots.
The "T" means that tritium (a low-level radioactive substance) was applied to make the hands and/or markers glow in the dark. The "T‹25" means the same thing, except it spells out that less than 25 milliCuries of radioactive material is used. See section 6.1 for more information about Tritium.
The lower-case Greek sigma means that the markers are made of solid gold.
A movement described as a "mecaquartz" is actually a quartz movement that contains many mechanical components. An example is the Jaeger LeCoultre (JLC) Caliber 631, which uses a quartz movement to drive not only an analog hour/minute/second display, but also mechanically drives a chronograph function (see 4.1, below). This differs from a typical quartz chronograph, where the chronograph functions are either digitally displayed in an LCD window (e.g. Breitling Aerospace), or where the chronograph hands are individually driven by separate motors (e.g. Seiko Flight Computer, with four separate motors).
A "mecaquartz" movement as that term is commonly used is not a quartz movement with a mechanical charging system, such as the Seiko Kinetic or Swatch Autoquartz.
Accutrons have a distinctive audible hum when operating, and their second hand is driven at such a high frequency that it truly appears to move continuously, unlike a mechanical watch (which vibrates at 10 Hz or less) or a modern quartz watch. Accutrons were the first major advance using electronics in timekeeping technology over mechanical watches.
However, it is important to periodically service a watch to ensure that the components are well-lubricated, and that the mechanism is free from dust, dirt, and moisture. Any water that gets inside a mechanical watch will wreak havoc with the precision mechanism inside, especially the anchor escapement and escape wheel which are typically made of steel.
The typical rule of thumb is to have the water resistance (i.e., the integrity of the seals in the crown, bezel, and caseback) of a watch checked every year or so, especially if used for sports or diving. With the development of modern synthetic lubricants, most manufacturers recommend a servicing every four or five years.
Finally, since the crown is often the only means by which the watch owner can adjust/abuse the movement inside the case, please read some Basics in handling the Crown
Why should I get a mechanical watch when a quartz watch is so much cheaper and more accurate?Yes, a quartz watch is cheaper and more accurate than a mechanical watch. A good mechanical watch can typically be made no more accurate than 2-3 seconds per day. Your typical inexpensive quartz is usually good to 0.5 seconds per day or better.
But mechanical watches are not about achieving the ultimate in accuracy. Craftsmanship, aesthetics, and tradition are all part of the allure. Because the wheel train of an analog quartz watch is not under constant stress from a wound mainspring, it does not need to be as finely finished, nor does it require painstaking skill and precision in assembly.
Mechanical watches are good enough for most people's everyday lives, and they call to our emotional side.
If one were going to own only a single watch, and wear it every day, an automatic would be a good choice, since the watch will be worn consistently enough to stay wound - the owner would never need to manually wind the watch, and would only need to adjust the time to compensate for drift and at changeover to daylight/summer time and back. (In fact, several early automatic movements dispensed with the crown and moved the time-setting mechanism onto the back, under the theory that the mechanism would only be accessed infrequently. This turned out to be a marketing flop - people liked the look and easy accessibility of the crown.)
For this reason, most commonly seen watches with more than a simple date window use automatic movements - this includes "triple date" calendars, annual calendars, perpetual calendars, and any of these combined with moonphases (see 5.3 for more information about calendars). With few exceptions (oddly enough, these seem to be more expensive watches), most manual wind watches have simpler calendars, although they may include other complications like chronographs
One caveat about automatics - if you have more than one watch that is worn regularly, the automatic winding advantage is lessened - the automatic may stop if not worn often enough. With some calendar mechanisms, this is can be an increased inconvenience when the watch is reset.
Finally, since frequently worn automatics are usually at or near a full state of wind most of the time, one may get the impression that they can be adjusted to be more accurate and consistent over the course of many days. This, in fact, is not necessarily the case, as a manual-wind watch that is wound consistently once per day can be tweaked so that the day to day variation is very small. In short, there is no definite performance advantage to an automatic - it is mostly a convenience.
All automatic watches have an overwind protection mechanism of one sort or another, to prevent breaking the mainspring once fully wound. In a typical system, the mainspring, which is wound at the central arbor of the barrel, is not rigidly attached to the outside of the barrel. Instead, there are a series of detents along the outer edge of the barrel that allow a stiffly constructed mainspring part called the bridle to slide along when an attempt to overwind is made. On some watches, a faint click can be heard when this happens, on others, it cannot be heard. It should be noted that this overwind protection is critical to avoid damage to the watch, and is reported to be one of the more tricky things to get right during a watch service because of the special lubricant needed to ensure proper operation.
It should be noted that the latest generation of autoquartz movements can store enough power to run the watch for several months (or even years in the case of the Seiko Auto-Relay); a mechanical automatic can only store as much power as contained in the mainspring - which is usually only 40 hours or so for most automatics.
The idea is quite simple: strap the automatic watch to a motor, which then moves the watch enough to keep it wound when not worn on the wrist. That way, one can choose to wear any watch at any time, and not have to reset the time or calendars. In theory, this device should be simple and cheap.
In practice, it's not as easy as it sounds. First, while an automatic watch has an overwind protection mechanism to avoid damage to the movement, if the overwind mechanism is constantly used for hours at a time (i.e. though constant turning, rather than the unpredictable movement of the human wrist), the lubrication of the mechanism is worn out faster. This means that watch winders must be designed to only make so many turns per day, and to let the watch sit. Furthermore, since automatic winding mechanisms vary from watch model to model, the winder must be designed to have an adjustable number and direction of turns per day. Finally, mechanical watches are considered luxury items, which means watch winders are doubly so - due to the small number of people who would actually want one.
All of this means that manufacturers for the consumer market must not only make their winders mechanically foolproof to avoid damaging watches, but they often construct the winder comparably to a jewelry box. The upshot of all this is that most consumer watch winders with programmable winding are expensive - often costing several hundred or thousand dollars.
While cheaper professional models exist, these often do not come with programmable settings, as the maker assumes that they would be used in a watchmaker's shop.
Last word - winders are not a necessity, they are a convenience. You should decide whether they are worth it based on whether you feel inconvenienced resetting your automatics occasionally, and whether they are worth it to you as a luxury item.
Figure out what is important to you in a watch, and find out whether the watch you're looking for has it. Don't ask people to make a sweeping judgment about the overall worthiness of a watch - you'll get way too many conflicting answers.
An "unadjusted" movement is a movement where no attempt has been made to ensure that the daily error rate in several orientations (positions) have been minimized across the positions. An "adjusted" movement, therefore, has had some extra care in ensuring that the variance in accuracy between several orientations is minimized.
Watches are typically adjusted to 2, 3, 4, 5, and 6 positions. Traditionally, they are ordered as follows:
A "regulated" movement is a when the overall rate of the entire movement (either adjusted or not) is brought into correct absolute timing. Unlike adjustment, this is a simple tweak, which moves the daily rates of all of the positions up or down without intentionally changing the relative rates in positions.
A chronometer is a watch which has passed a test given by the Contrôle Officiel Suisse des Chronometres, or COSC. The COSC is an official Swiss government agency which tests watches to ensure that they fit within a narrow-but-usually-obtainable window of acceptable error (i.e., the rate in all positions falls into the range of -4 seconds/day to +6 seconds/day). While some watch companies tout their products as having a COSC certificate, it really is not that difficult to pass the test, and over 95% of the watches submitted pass. Another factor to consider is that the COSC does not test watches as they are sold in the store, but movements fitted with a temporary case, dial and hands. In addition, the COSC certificate cannot say anything about how the movement was handled after testing. Several watch manufacturers actually put more stringent tests than the COSC procedures on all of their watch production (the JLC Master Control 1000-Hour series is probably the most well known.)
A chronograph is a watch that tells the time of day and also allows the user to time events of short-to-medium durations (i.e. from a few seconds to a few hours, typically). This is usually done in a mechanical watch through the central seconds hand, and one or more subdials (the regular, or continuous seconds, is also located on a dial). Chronographs are of varying usefulness, and are an interesting complication to put on a watch, as they often give the watch a sporty image. In addition to elapsed time, chronographs are often fitted with several scales designed to measure other things, such as pulse rate or units manufactured per hour. A typical modern chronograph is operated with two pushers: one to start and stop the timing, and a second to reset the hands to zero when the timing is stopped. (In some older chronos with only one-button for control, the sequence of pushes was start-stop-reset - there was no provision to continue timing once the mechanism was stopped.)
Interestingly, three languages describe this function in different ways: "Rattrapante" is the French term for "catch up" (describing the motion of the split hand); the German term for this function is "Doppelchronograph", or double chronograph; the English term is "Split Seconds" (describing the appearance of the second hand when the function is activated).
An example of this function is on the IWC Doppelchronograph or Breitling Chronoracer (a mecaquartz (!) rattrapante).
Examples of chronos with flyback include the Blancpain Flyback Chronograph, and the Breguet Type XX Aeronavale.
The column wheel was one of the successful early designs to ensure that none of the above happened. If you can visualize the top of a castle turret, with tooth-like battlements, this is what a column wheel looks like. The pushers that control the chronograph rotate this wheel, and the various parts of the chronograph are controlled by fingers that fall into and out of the spaces between the teeth. This ensures that each of the chronograph parts is coordinated properly.
Because producing and finishing a column wheel is labor-intensive, a simpler, easier method of producing chronographs was needed to keep this complication from appearing only in very expensive watches. The most common method is to use an oscillating pinion to coordinate the chronograph start, stop, and reset (i.e. a cam shaped device that rotates back and forth as the various functions are activated.) This allows for reliable operation without nearly as much fiddling and hand adjustment as a column wheel requires, and the pinion can be built using pieces of stamped metal.
These days, relatively few column wheel designs are still being produced - the Zenith El Primero, some Lemania and F. Piguet movements, and (interestingly) a F. Piguet rattrapante mecaquartz are examples. The most common movements, such as the Valjoux 7750 and various Lemania movements (1874, 5100), are not of column wheel design.
Certainly column wheels are a traditional method of coordinating the chronograph components, and tradition counts for a lot.
On the other hand, the newer, non-column wheel movements have certainly proved themselves in a variety of demanding situations. Both the column-wheel and non-column-wheel version of the Omega Speedmaster were certified for space flight by NASA. And the non-column-wheel Lemania 5100 has been one of the few mechanical movements to be accepted as sufficiently rugged by modern military forces.
So - much like the question of which watch is best, I suggest that one think about which factors are personally most important in a chronograph, and make the decision from there.
Chronographs of all flavors have been dealt with in Section 4. This section will discuss some of the more commonly seen (or at least coveted) complications.
This can be a very useful complication, as it lets one know whether a watch is wound before putting it on. This is true for automatics (which may be in any state of wind) or long power reserve watches (such as the Eberhard 8 days, Lange 1, or the new Patek 5100 ten-day reserve).
Some less complex calendars are also available:
In even the best watches there are small variations between the different vertical orientations (i.e. in the crown up, down, left, or right positions). This is largely due to the combined effect of gravity, the hairspring shape and attachment point on the balance staff and cock, and the regulator pins.
Unlike a wristwatch, a pocketwatch worn in a vest will spend the majority of its time in a vertical position. Therefore 18th/19th century watchmaker Abraham Louis Breguet allegedly decided that, for the absolute best accuracy, some means of balancing out the effects of gravity in the various orientations was needed. The solution he devised placed the balance wheel, escape lever, and escape wheel in a cage, which then rotated as a unit within the movement as a result of the normal escapement process. In this way, the overall effects of gravity get balanced out, as the escapement of the movement never spends any significant time in one vertical position.
However, this solution is very complex, with the result that a tourbillon has become more a statement about the watchmaker's skill rather than having any real performance advantage - starting price on a tourbillon is roughly in the £35,000 range. The performance advantage is even further nullified by the fact that wristwatches spend a less predictable amount of time in less predictable positions.
Watches which do strike "en passsant" (in passing) automatically are called Petit or Grande Sonneries.
Repeaters currently come in several varieties, based on the smallest unit of time which they can indicate:
Radium was used after about 1900 as a means of illuminating watch hands and markers at night. It was widely used until the 1940's or so, when the hazards of radiation were (belatedly) understood. Since them, a less powerful radioactive source, tritium (a kind of hydrogen) has been used. At the time of this writing (November, 2000), tritium is being phased out of watch dials, partially due to availability of tritium, and partially due to the development of non-radioactive luminous compounds like Luminova which "hold their charge" of light better.
The main victims of radium were the watch dial painters, who were encouraged to keep a fine point on their paint brushes by licking the brush end. The wearers of the watch receive only a small dose of additional radiation per year, much less than the natural background radiation.
Mineral crystal is a kind of glass, which is more scratch resistant than acrylic, but not as as good as sapphire. Mineral crystals are also somewhat better at shatter resistance compared with sapphire. Unlike acrylic, scratches in mineral glass are more difficult to buff out; and unlike sapphire, mineral glass will scratch. In my opinion, the mineral crystal seems to be a poor compromise between the two extremes.
A sapphire crystal is indeed made of synthetic sapphire, which is a transparent form of corundum, or aluminum oxide (Al2O3). It is extremely hard (Moh's scale 9), and will resist scratching by most substances short of diamonds. However, if struck sharply and from the correct direction, sapphire will shatter. Despite the relatively large size compared with sapphire gemstones, sapphire crystals aren't very expensive (~$20). (Another fun fact - the windows built in to grocery store checkout lines which scan for the bar code on products are often made of synthetic sapphire - for the same reasons that watch crystals are!)
Note that there are also purpose-made polishes for this purpose, such as Polywatch or Crystal-Kleer or Brasso.
(Planet4watches.com: We cannot be held responsible if you try this for yourself, and end up ruining your watch. This procedure is intended for people willing to take responsibility for their own actions only.)
9K = 9/24 purity of gold = 37.5% purity (sometimes seen in vintage and/or UK market watch cases, along with 10K gold)
14K = 14/24 purity of gold = 58.3% (sometimes marked 583 or 585 in gold hallmarks)
18K = 18/24 purity of gold = 75% (sometimes marked 750 in gold hallmarks)
24K = 24/24 purity of gold = 100%, which I'm guessing you'll never see in watch cases.
So, that JLC you were looking at in 18K gold has a case made of real 75% purity solid gold. No wonder it's so expensive. :-)
(BTW, bracelets sold with solid gold watches are often themselves solid gold - which as you might expect adds significantly to the price.)
This practice was common until the 1960's, but has been largely replaced by plating processes.
Rolled-gold plate was another vintage method of plating gold, except the gold was rolled out flat before being bonded to the base metal. This process has been supplanted largely by electrochemical plating and PVD.
Platinum is a very heavy metal, and gives a shiny white metal appearance. Unlike gold, pure platinum is fairly hard and resistant to scratches (similar to hard stainless steel). For this reason, it is often used in 95% purity (i.e. Pt 950). However, raw platinum is more expensive to use, not only because of its rarity, but also because it is used in higher purities and requires more effort to work into a final shape.
Titanium is a relatively light-weight metal, with a hardness exceeding that of most steels. It also has a poor heat transfer capability, which means that it won't carry heat away from your skin as quickly as steel or aluminum (i.e. it will feel warmer to the touch - sometimes you'll see claims that titanium "remains at skin temperature" - this is technically incorrect, any more than a small piece of wood stays at skin temperature). Several varieties of titanium are available. Titanium has some interesting mechanical properties: it can "rip" when cut so it is difficult to machine, and two pieces of titanium pressed together can "weld" themselves together. This latter property is why it is important that watches with titanium cases and backs have the casebacks removed periodically - the threads can actually rip out of the case if left undisturbed too long.
Other case materials which one will run across occasionally (especially on the vintage market) are Sterling Silver (92.5% purity silver), Coin silver (80% purity silver), nickel silver or silveroid (not silver, but 66% copper, 24% zinc, and 10% nickel), nickel, and nickel plated steel. Also, more recently, one can even find watch cases made of ceramic (zirconium oxide, as used recently by IWC) and aluminum (used in conjunction with other metals, as currently used by Porsche Design and BVLGARI.)
For gold filled or gold plate, I would recommend that you leave them alone - you don't want to remove any more of the finish than already exists!