TrustedWatch - All about watches




Here you can find any information concerning manufacturing, care, cleaning and maintenance of your watch. If you should have a question which is not answered here please feel free to contact us.


Question: Which possibilities does a watchmaker have to examine the water-resistance?

Answer: The watchmaker has different possibilities to prove the water-resistance of the watch:

Question: what is the difference between “water proof” and “water resistant”?

Answer: The older term “water proof” was replaced by “water resistant”.

Question: makes the watch water-resistant and what does ATM stand for?

Answer: Normally on most watches the maximum pressure is registered. On the back of the case the pressure is normally indicated in ATM, whereas on the dial in metres. The following table gives you an overview:

Question: How often do the batteries in my quartz watch need to be checked?

Answer: The batteries in your quartz watch should be checked at least every two years. The battery life depends on many factors. Not only outside conditions such as temperature changes, but also the type and your individual usage are determinants. Usually quartz watches with additional functions need more power than quartz watches without. Therefore it is not possible to make general statements on battery life.

Principally the batteries should be replaced at least every two years, however. Expired batteries may leak corrosive fluids into your watch causing serious damage in the movement.

Question: What are watch crystals made of?

Answer: There are 3 categories of watch crystals: Plexi crystals, mineral crystals and sapphire crystals. Each of them has different characteristics, different application ranges and furthermore different fashion aspects. However, there are different quality standards within the categories.

Plexi crystal
Also referred to as hesalith, acrylic glass or plexiglass. It consists of Polymethylmethacrylate (PMMA). It is lightweight, therefore not very likely to shatter but most likely to become scratched.

The chemical formula is silicon dioxideSiO2. Good mineral glass is not used for window panes. While manufacturing, the surface of good mineral crystals is hardened during a complicated chemical process. Minerals are harder than plexi glass, they are osmotic and do not yellow. But also minerals can be shattered. This can be very harmful to the movement, as small splinter of glass can damage it.

Among the crystals, sapphire is the hardest substance. Sapphires are manufactured synthetically by the Verneuil-process. The disadvantage of sapphire is the high refractive index. Mostly, this results in annoying reflections on the crystal. Therefore, a non-reflection coating is applied on valuable watches to prevent glare.

Question: There are scratches on the crystal of my watch. Can the scratches be removed?

Answer: Please have the crystals replaced as soon as possible when scratches occur. If the crystal has a scratch, water or dust can enter the watch.

Question: How can I distinguish mineral from sapphire crystal?

Answer: Solely a professional can distinguish the different crystals with a diamond tester. Unfortunately, there is no other method of testing.

Question: How long does a leather strap last?

Answer: Usually 1 or not more than 2 years, when you wear your watch every day. Then, at the latest, you should replace the leather strap. Leather is natural material hence it can absorb moisture and dirt. Especially water can seriously affect the material; accordingly certain kinds of leather (e.g. croc) should not come into contact with water at all. To avoid allergic reactions and for hygienic reasons, we recommend to replace the leather strap regularly.

Question: Can I store my watch (e.g. in a safe) for a long time?

Mechanical watches (manual winding, automatic):
A longer storage is no problem. But one has to keep in mind that the oil will run dry gradually. Consequently also an unworn watch should be revised every 4 or 5 years.

Quartz watches:
If storing your watch for a year or longer you should have the batteries removed by a watchmaker. Expired batteries may leak if they remain in the watch. The corrosive fluids may cause serious damage in the movement.

Technical Questions:

Question: How does the tachymeter scale work?

Answer: A tachymeter is used for measuring speed and was applied when cars did not have a tachometer yet. For measuring speed a measured section of one mile is required. The chronograph is started at a mile marker. At the next mile marker, the point on the scale adjacent to the second hand indicates the speed (in miles per hour) of travel between the two mile markers.
So the tachymeter scale is a scale, which measures the speed=path/time(v=s/t); the speed is indicated in miles per hour.

Question: Can magnetic fields affect my watch?

Answer: Principally, you should avoid exposure of your watch to magnetic fields over a period of time. All mechanical watches contain sensitive electronic measuring devices, which can be disturbed or even destroyed. Therefore, in order to protect a watch from the influence of magnetic fields, the movement of some watches was surrounded by an inner case of soft iron which deflects the streamlines of the magnetic field.

Question: : I have bought a manual winding watch or automatic watch for the first time. What shall I do first?

Answer: We recommend taking your time in order to wind it up slowly and evenly. When you wind up a watch, strong forces affect the concerned gear wheels. If you should wind up the watch too fast it can seriously damage the gear wheels. By winding up the watch slowly and evenly, these devices will not be worn needlessly.

Question: How do I wind up my watch perfectly?

Answer: The watch is fully wound up when you cannot wind the crown clockwise any further or when the crown resists further turning.
The spring is hooked to the barrel and the arbor. When wound, the spring is slowly pulled completely inwards towards the barrel arbor. If this state is reached the watch is fully wound up. If an attempt is made to continue winding despite this resistance, the spring may break and the abruptly released energy could seriously damage the wheels of the movement.

Question: When is my watch fully wound up?

Answer: Bei Handaufzuguhren ist die Uhr voll aufgezogen, wenn Sie die Krone nicht mehr weiter im Uhrzeigersinn, also rechts herum, drehen können oder wenn Sie beim Aufziehen einen Widerstand spüren.

Die Zugfeder ist bei Handaufzuguhren mit einem Ende an der Innenwandung des Federhauses befestigt, mit dem anderen Ende am Federkern. Beim Aufziehen wird diese Feder langsam vollständig um den Federkern gewickelt. Wenn dieser Zustand erreicht ist, ist die Uhr voll aufgezogen. Versuchen Sie jetzt Ihre Uhr weiter aufzuziehen, kann die Zugfeder reissen und die dadurch schlagartig freiwerdende Energie kann die Verzahnungen des Räderwerks stark beschädigen.

Question: How often do I have to wind up my watch?

Answer: If the watch is worn daily, it should be wound daily – ideally in the morning, if possible, because the spring in mechanical watches cannot generate the same energy constantly. This energy depends on how far the spring is wound. When the spring is fully wound, the available energy is on its peak. When the spring has run down, the energy is low. When you wind up your watch in the morning you will have optimum energy throughout the day and therefore more consistency and accurate timekeeping.

Question: How should I wind my automatic watch after the mainspring has run down?

Answer: When winding an automatic, we recommend counting the number of times you turn the crown. Thirty to forty rotations guarantee optimum torque. Please note: If you have a watch with a screwdown crown, unscrew it counter clockwise until it is released from the threads. Only then you can begin to turn the crown.

Question: If I do not wear my watch at night, do I have to wind it up again?

Answer: If you wear your watch every day except for the nights you do not have to wind it up additionally by hand. When an automatic watch is fully wound up, the power reserve, which is the saved energy of the spring, lasts at least 38 hours. The power reserve depends on the movement. Please note, that a certain minimum of movement is required when you wear the watch. If this should not be possible you have to wind up your automatic watch every day with thirty to forty rotations of the crown, just like a manual winding watch.

Question: What causes rate deviations?

Answer: Normally the movement of valued watches is adjusted in different positions to an average of -0 / +7 seconds per day. That is a valued watch never gains or loses a few seconds over the period of time, but more precisely, it always varies with the same value. It differs from movement to movement.

The owner’s individual habits of wearing also play a decisive role in the rate variations. An automatic movement of an energetic person runs differently than that of a rather calm person. Thus a deviation in rate is primarily a matter of timing check and habit’s of wearing, not a matter of function. This is different when you have an already repaired watch.

Question: Why does it often say IIII instead of IV on many dials?

Answer: Nobody knows exactly, but there are following assumptions:


Question: Why do watches with the same movement/calibre have such different prices?

Answer: Many brands have various suppliers for their movements. Today it is not difficult any more to find out, what movement the watch has. Thus it is possible, that a low priced watch has the “same” movement as a valued watch. Often, this provokes incomprehension.

On the one hand, the movement certainly is a great component of a watch, but on the other hand, there are several more, such as form and construction of the case, refinement, dial, etc. Not least, an important price and product component is service, attendance and brand equity. This should be considered when buying a watch.

Question: Are there international price differences among exclusive watches?

Answer: Very often it is alleged that watches are cheaper abroad. In contrast, the watch industry claims that the price is the same for all authorized dealers, or, that if a price difference exists, it would be higher abroad.

It is obvious, that the respective exchange rate has to be considered. However, according to experience current models are mostly cheaper in Switzerland than elsewhere. High prices abroad are mostly due to high rates of taxations, though dealers are more willing to grant a discount due to overstock and tough foreign competition.


Question: What is the difference between a chronometer and a chronograph?

Answer: The term chronometer is registered. Only a watch, whose movement was tested by an officially recognized testing laboratory and met the performance criteria, may use the term chronometer on it. In Germany, the testing laboratory is in Glashütte (see In Switzerland it is the Controlé official Suisse des chronometers, or abbreviated C.O.S.C. (see

Question: What is measured by the laboratories?

Answer: a mechanical chronometer has to meet the given performance criteria. However this running test is relative, because it refers to a non-running movement, which was tested over a certain period of time (15 days), in a certain place, in a certain altitude and under certain conditions.

Question: When is a watch "Swiss-made"?

Answer: A movement is to be regarded Swiss, when:

Following rules are applied in calculating the value of the Swiss manufactured components:

Question: What are the preconditions for using the term „Swiss-made“

Answer: The labelling “Switzerland”, “Swiss-Made”, ”Swiss”, “Swiss product”, “Made in Swiss”, “Swiss quality” or other terms, which contain the Swiss name or can be confused with it, can only be used on Swiss watches and movements.