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What is a stone in a mechanical watch. Gems of Time

On the dials of high-quality mechanical watches, not only the brand and model are indicated, but also the number of stones. Inscriptions like "15 stones" on grandfather's "Victory" in childhood were always very intriguing. When it was possible to find out that it was rubies, the watch began to seem one of the most valuable things in the house.

Many have grown up and figured out why these stones are actually in the watch. If you still have not revealed this secret for yourself, then our material will help fill the gap.

How mechanical watches work

If you ask a specialist about the purpose of stones in watches, he will answer unequivocally: they are needed to stabilize friction and reduce wear on the contacting parts of the mechanism. That's all, simple and clear. Unless, of course, you have an engineering background. For the rest, a translation into a simpler language is needed.

To do this, you should at least in general terms understand how the clockwork works. The source of energy for it is a spring made in the form of a flat steel tape. When winding the watch, it twists and stores energy. The second end of the spring band is attached to the wall of the drum, which rotates and transfers the accumulated energy to the gears. Several of these gears (usually three or more depending on the layout of the watch) form a wheel system. It transfers energy.

Why do the gears not spend all the energy at once, but rotate gradually? A trigger mechanism is used to control the speed of rotation. It is he who does not allow the gears to spin faster than necessary. The trigger mechanism is controlled by a balance regulator. This is a kind of pendulum that works regardless of the position of the clock in space. It has a coil spring that causes the wheel to spin in one direction or the other at a constant frequency. This is how seconds are counted, which then turn into minutes and hours, reflected on the dial.

Stone is a bearing, but not only

There are many rotating parts in the clock mechanism, which are mounted on axes. The main axles are under significant and permanent stress. On the one hand, the mainspring exerts pressure, on the other hand, the rotation is limited by the regulator.

In any mechanism with rotating axes, it is necessary to minimize their friction against a fixed base. This is necessary both to reduce wear and to reduce energy consumption. Usually bearings are used for this, but in watches they are replaced by the same stones.

The axle bearings in watch movements are very thin. In such conditions, stones are needed not only to reduce friction, but also to increase the life of rotating parts. Stones are not subject to corrosion and wear. If they are preliminarily well polished, then their surface remains clean and perfectly even for a long time.

Stones, in addition to the supports of the clockwork, are also used in other places. For example, it is the wear-resistant mineral that is fixed on the pendulum in order to constantly hit the horn of the anchor fork. This is the so-called impulse stone.

Regardless of the type and location of installation, all the stones in the watch mechanism solve a common task - they reduce the wear rate. With the friction of metal on metal, it would occur much faster. In addition, the stones hold a special watch lubricant. To do this, when drilling, they are given a special shape.

About the jewel and the number of stones

Here we are forced to immediately disappoint - natural rubies and diamonds are rare in modern watches. They are used only by luxury manufacturers in limited editions or models made to order. In the bulk, synthetic rubies and sapphires are inserted into the mechanisms. For example, Seiko in Japan has a subsidiary dedicated solely to stone making. Synthetic rubies are no worse than natural rubies, and often better due to the absence of impurities and a more uniform structure.

The number of stones is another interesting and exciting question for many. How many of them should be in a good model? Is 20 pieces enough, or will a watch with 40 jewels be twice as good in proportion to their number?

It is wrong to evaluate the quality of a watch only by the number of stones. If there are 17-25 stones in the mechanism, then this is quite enough to make all significant bearings from rubies. There is nowhere to put more than 27 stones on an ordinary watch with three hands and automatic winding. If the manufacturer indicates 40 or more functional stones, then almost always it is a chronograph or an even more complex mechanism.

Some factories deliberately overestimate the number of stones, knowing that this indicator is positively perceived by the buyer. In such cases, additional rubies are placed in places where it is quite possible to do without them.

However, not always a large number of stones is a hoax. Certain reputable brands do develop complex movements, which can contain more than 100 stones.

In such a situation, when choosing a watch by the number of stones, you need to figure out whether the functionality of the mechanism corresponds to this indicator.

TECHNICAL REASONS

The important parts of a mechanical watch are mainly those that move, i.e. the gears, the balance and the regulator. In the old days, the pivot points of these parts rotated directly in holes that were drilled in two thick brass sheets separated by posts. To facilitate assembly and repair, the top board was later replaced with separate elements called "panels".

The lower copper plate (called the "base plate") was drilled with small holes through which the ends of the rotating rods rested. These holes also contained small oil sinks from which oil flowed into the holes to lubricate the friction points of the turns. Over time, they had to be cleaned, because. the resulting combination of oil and dust formed an abrasive that acted like sandpaper, slowly filing away the softer base of the plate and to some extent even the harder steel rods. With prolonged use, the abrasive action of the oil dust mixture, working in concert with the turning action of the centers, made the holes oval. In this case, the clock would start running randomly and eventually stop.

These observations led watchmakers to look for a material that was stronger and would withstand more wear from the centers. The material they settled on was ruby, second only to diamond in hardness.

A LITTLE HISTORY

The use of the ruby takes us back to 18th century England (the cradle of qualitative time measurement), where watchmakers first had the idea of using small ruby balls to support centers of balance. Ruby processing technique was invented by the Swiss optician and astronomer, Nicholas Fatio, who sailed to England in the hope of implementing his invention. He tried to get a "royal privilege" for his technique, but Fatio did not get it and as a result, other skilled workers began to manufacture rubies for watches.

In those days, these stones were second-rate, not popular in the jewelry trade. The technique to precisely cut rubies gave British watchmaking excellence for some 20 years. Thereafter, French watchmakers such as Abraham-Louis Breguet brought the techniques of the English masters to France. This was the beginning of the end of the British monopoly.

For many years, this relatively costly, labor-intensive technique has limited production to extremely high quality and expensive watches. Slowly, the manufacture of such watches has become more industrialized and their parts more accessible to other aspects of watchmaking.

Creating Synthetic Rubies:

top picture - creation of elongated pear-shaped parts of an artificial crystal.

bottom picture - the pear-shaped pieces are cut using a diamond cutting tool. The slices are then cut in half, into squares and circles ranging in size from 0.3 to 0.5 mm in thickness and 1.15 to 2.55 mm in diameter.

SYNTHETIC RUBIES

A further decrease in price accompanied the creation of synthetic rubies based on a method developed in 1902 by Auguste Verneuil, professor at the Paris Conservatory of Arts and Crafts. In fact, synthetic rubies, just like their natural counterparts, are corundum, that is, transparent aluminum oxide.

In the industrial fabrication process, the base constituent alumina (alumina) undergoes a series of operations, i.e. refining, heating, alloying and crystallization, which results in pear-shaped artificial ruby pieces. Chromium oxide is added to give the red color of natural rubies.

The large-scale manufacture of rubies has allowed the creation in large quantities of synthetic stones more uniform in quality than those found in nature. The jewelry trade takes most of these stones. In watchmaking, the cost of rubies came mainly due to labor (training needed), as the cost of raw materials was relatively low. Having said that, it should be noted that approximately 90% of the ruby is destroyed and only the remaining 10% is usable for watches.

COMMERCIAL TRICK?

In the mind of the public, the idea that a watch contains jewelry gives it a certain added value of prestige. Manufacturers were quick to exploit this belief and began adding unnecessary stones to increase the price of their products. The term "upjeweling" was an American term coined to refer to this dubious practice, which was quite widespread in the US at the time. Until it was overturned by the US Customs, which rejected "upjeweled" imports from entering the country. There are some people who suggest that their real motives may have been less noble and that this was just a sort of camouflage protectionism for the American watch industry.

Today, Swiss watchmakers no longer use this dubious practice, and their advertising is not based on the number of jewels in a movement. The total number of rubies, i.e. "jewelry", may change. In simple manual mechanical watches, the number of stones varies from a minimum of 14 to a maximum of 19. In automatic or more complex watches, the number of rubies is higher. One day, someone started a rumor that a repairman stole rubies from watches and replaced them with copper parts. This is a completely baseless myth. For a watchmaker, it would take a lot of effort to remove rubies and replace them, and would certainly not be worth his time, given that imitation rubies cost a few cents.

To sum it all up, the presence of ruby stones in a watch is of course a factor that adds to the quality of the watch. They are indispensable for the long and correct functioning of a good quality watch.

material taken from the site http://www.europastar.com/

Very often, on the case of a good mechanical watch, you can find the markings “17 stones”, “21 stones” or even “100 stones”. What do these inscriptions mean? What kind of stones are we talking about? And most importantly, how does the number of stones affect the cost of a watch?

Stones in watches - the main purpose

First of all, it is worth noting that we are not talking about the decorative design of the watch case, but the stones involved directly in the clockwork. According to the official definition given in NIHS 94-10, adopted in 1965 by the Swiss organization NIHS (Normes de l'industrie Horloge Suisse), the stones in a watch mechanism have the function of "stabilizing friction and reducing the degree of wear of the contact surfaces of the movement." In addition, the stones can work as a watch lubrication accumulator.

Mechanical watches, especially wrist watches, are an incredibly complex object from an engineering point of view. Inside the small case are several hundred parts, the thickness of which can be calculated in microns. Some of the parts of watch movements make more than 7,000 vibrations per hour, around the clock, 7 days a week. Despite the fact that modern watch mechanisms are made of the latest superalloys and using the most advanced technologies, such a heavy load leads to rapid wear of the metal parts of the mechanism and, accordingly, violations of the accuracy of movement.

Precious stones are used as supports for the axes of the main parts of the mechanism. The stones have a denser crystalline structure, they are easier to process and polish and are not subject to corrosion. In addition, some stones have a much higher wettability coefficient than metals, so they can also work as an ideal keeper of watch lubricants.

History and modernity

For the first time, stones in watch mechanisms began to be used at the beginning of the 18th century, when pocket watches came into fashion. In that era, natural rubies were used in the manufacture of watches. Modern technologies allow people to grow artificial stones, which are not inferior to natural ones in their qualities, but have a lower cost.

Today, in the manufacture of watch movements, artificial rubies and sapphires are mainly used. The number of stones required for the simplest mechanism without complications is 17 (five stones for the pendulum, four for the anchor, two for the ratchet gear and six for driving the second hand). As the number of complications in watches grows, so does the number of jewels. For example, in self-winding watches there are already 23 of them, if there is a perpetual calendar - even more.

Better less is better

The Vacheron Constantin Reference 57260 watch, which is currently considered the most complex in the world, has 57 different complications and 242 jewels in the movement. But this is one of the extreme cases. In modern mechanical watches, it is customary to use 21 stones. Curious situations are also known when the number of jewels in a watch is artificially increased to raise the model's prestige.

The main thing to understand is that if the manufacturer indicates “100 stones” on the watch case, and at the same time it is clearly not Vacheron Constantin 57260 or Patek Philippe Caliber 89, then the only function of most of the stones in such watches is to increase the cost.

Quartz watches do without stones at all, or have only 2 stones that serve as supports for the stepper motor rotor.

No matter how many stones and complications your watch has, their main function is to measure time as accurately as possible. And if they cope with it, the rest becomes not so important.

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