Technology Glossary

Glass-like product made from polyacrylic esters.

It is highly break resistance and is resistant to weather and corrosion. Small scratches can easily be polished out.

Distance of oscillation (swing or beat).

The amplitude is the maximum angle of rotation of the balance between the point of equilibrium and one of the reversal points of the oscillation. The average amplitude values of most watch movements made today are between 250° and 300°. As the lubricant ages, this value gradually falls.

DIAPAL Technology deals with this problem at the root, by dispensing with the need for oil altogether.

Decorative processing of edge contours, particularly on the bridges and cocks of a high quality movement.

During angling, a decorative bevelled edge is created (the edge is ‘angled’). Angling is a highly skilled finishing technique used instead of the conventional deburring/rounding of edge contours.

According to DIN, watches which do not stop when exposed to a magnetic field (see magnetism) and the accuracy of which does not exceed specified limits when exposed to a magnetic field may be described as antimagnetic.

DIN guideline 8309 stipulates that mechanical watches are antimagnetic if their rate change does not exceed +/- 30 seconds per day after exposure to a magnetic field of 6 mT (corresponds to 4800 A/M) (movement diameter larger than 20 mm). The watch should also not stop when exposed to a magnetic field of this strength.

Mechanical watches react to magnetic fields primarily due to the fact that they contain temperature-compensating hairsprings (see Nivarox).

At Sinn, we offer additional magnetic field protection in some watches.

Zirconium-oxide ceramics
Technical ceramics that are made from the oxide of the metallic element ‘zirconium’ using a sintering process. The precise chemical name is zirconium dioxide. This raw material belongs to the group of oxide ceramics which also includes aluminium oxide, known in watchmaking through (polycrystalline) sapphire glass and rubies.

The term ‘ceramics’ is generally understood to be a much narrower term than the one used today in technical contexts. Whilst people mostly think of clay and porcelain products – i.e. special silicate ceramics – when ceramics are mentioned, they have also long been widely used in technology such as in ball bearings, plain bearings or engine parts. First amongst the modern types of ceramics used here is zirconium oxide. Whereas conventional ceramics dating back far into the annals of history can be produced from natural raw materials and at relatively low firing temperatures, the technical ceramics introduced over the last 100 years only obtain their special properties by using high-purity synthetic starting materials and applying high temperatures and pressures.

Beginning with a very fine powder (less than 1 micron particle diameter), a sintering process is used to produce zirconium ceramics, just like in the production of traditional ceramics. The temperatures almost reach the melting point of the ceramic powder and induce the fine powder particles to cake. This sintering process is combined with the ‘hot isostatic pressing’ process in the production of technical zirconium ceramics, where it is fired under high pressure (acting from all sides) to produce a significantly thicker material with much finer crystals, as opposed to traditional firing technology. Among the resulting properties of this material, the main ones are:

• high heat resistance, low thermal expansion
• non-conductive
• biocompatibility
• high corrosion resistance
• high hardness levels with equally high levels of mechanical strength

The two latter points make the materials very attractive to watchmakers. Zirconium oxide ceramics are characterised by very high resistance to scratches, but at the same time they have a mechanical strength that is more than double that of sapphire glass. This means that zirconium ceramics are not prone to breakage despite their high hardness level.

By adding coloured particles, the naturally white zirconium dioxide can take on a black or coloured appearance.

The balance, in combination with the hairspring, constitutes the oscillation system of a mechanical watch.

Balance wheel with hairspring.

Model R500. The racing stopwatch made of high-strength titanium was the first bullhead chronograph in the Sinn Spezialuhren collection.

Another word for a movement.

The term is usually used in connection with a numerical movement name such as ‘Calibre ETA 7750’, for example. Unlike calibre information in weapons technology, in watchmaking the term ‘calibre’ has nothing to do with the size of the movement.

Outer bezel with a special design to prevent it from being lost.

Bezels are conventionally attached to the body of the case using a snap-in mechanism. If knocked, the ring can, in the worst case, become detached and the set time lost. Many our watches are therefore fitted with a safety system which overcomes this design weakness.

The captive safety bezel in the U1000 diver's chronograph also includes a further safety feature besides its captive design: rotation protection.

See Sinn Technology: Captive Safety Bezel.

A chronograph is a timepiece with a stop mechanism which can be used to time the length of a particular procedure.

Conditions which movements must meet to fulfill the chronometer standard.

Watches or movements with particularly accurate running, confirmed by an official certificate, are designated chronometers. Chronometer movements have to be given a serial number to ensure that the certificate and the movement can be uniquely matched. Chronometer tests are currently carried out and documented almost exclusively by the C.O.S.C. (Contrôle Officiel Suisse des Chronomètres, an independent public-service organization in Switzerland). Just recently, however, the Landesamt für Meß- und Eichwesen Thüringen (Thuringian State Office for Measurement and Calibration) in Glashütte has started offering chronometer tests as the accreditation office of the German Calibration Service in Germany.

The chronometer quality of a mechanical watch movement is determined in part by the special workmanship of certain movement components, partly by precise regulation of the watch. We only use the highest quality products provided by Swiss movement manufacturers in Sinn watches. Basically all these movements can be regulated as chronometers. If desired, our watches can be given a fine-adjustment, i.e. they are of chronometer quality, but are supplied without a certificate.

The specifications of a mechanical chronometer movement include a number of rate accuracy aspects: e.g. the effect of position on the rate, the stability of the rate in each individual position and the temperature dependency of the rate. There is an international standard (ISO 3159) for mechanical movements which correspond to national standard systems (DIN 8319, part 1 and NIHS 95-11).

Because the accuracy of a mechanical watch generally depends on its spatial orientation in the Earth's field of gravity, five test positions for observing the escapement are distinguished (e.g. "dial top", "dial bottom" etc.). The mean of the accuracy values measured in the five test positions should remain within a range of -4 to +6 seconds per day (24 hours) at room temperature (23ºC). This standard, by itself, is not particularly exacting and would probably be fulfilled by any modern mass-production caliber. However, a chronometer movement must also achieve this mean value with no appreciable accuracy differences between the individual positions. The largest accuracy difference between an upright and horizontal position (more precisely: between "crown left" and "dial top") should be no more than -6 to +8 seconds per day. For the remaining positions: each individual position value should not differ from the average of all five positions by more than 10 seconds per day.

Further demands are placed on the stability of the accuracy in each individual test position. The watch should not deviate by more than 5 seconds per day in any given position (at a constant temperature of 23°C). The mean of the deviations observed in the individual test positions should also be no greater than 2 seconds per day. Critical demands are also placed on the temperature dependency of the watch’s accuracy. The watch’s accuracy is tested within a temperature range of 8°C to 38°C. The deviation per degree Celsius and day should not exceed +/- 0.6 seconds. Finally there is a test to ensure that the watch regains its accuracy at 23°C, after the temperature change. In a given test position, the accuracy may not differ from the mean accuracy in this position measured before the temperature change by more than +/- 5 seconds per day.

In chronograph movements, the accuracy difference is checked with the stop function turned on and off. All accuracy measurements are carried out without the use of an electronic timing machine, i.e. the time is read off directly after 24 hours as measured on a test dial. The entire chronometer test takes a total of 15 days.

Up to now there has been no international standard (ISO) for quartz chronometers. In the meantime, the technical possibilities of series production have overtaken the requirements of the Swiss and German standard systems (see e.g. DIN standard 8319, part 2, from 1978). In 2001 the Swiss testing organization C.O.S.C. therefore formulated new criteria for its own testing practice. This placed more stringent requirements on quartz chronometer movements. The test criteria are designed so that quartz movements without special temperature compensation cannot pass the test.

At SINN, we use thermo-compensated ETA movements with a quartz frequency of just over 32 kHz in our UX and 434 models. Although quartz movements with an even higher running accuracy are technically possible in the form of mega-Hertz oscillators, they were only produced temporarily and in small quantities due to their high power consumption and high manufacturing costs.

Due to their temperature compensation, the ETA quartz movements we use are around twenty times more accurate than a conventional quartz movement regulated to room temperature and are currently the most accurate autonomous wristwatch movements.

A chronograph in which the start, stop and reset functions are controlled by a column wheel.

A column wheel, also called a ratchet wheel, is a pivoting sawtoothed gear wheel to which several columns are attached at right angles. It is made as a single piece, polished and hardened. According to the positioning of the column wheel, holes open up for the levers of the chronograph mechanism which can resolve a previously existing blockage, or the lever touches a column and is lifted up due to its slanted side surfaces. The positioning of the column wheel is altered via the aforementioned sawtoothing at the base of the column wheel.

A coulmn wheel chronograph is much more challenging to produce in terms of manufacturing processes than the usual shifting link. These chronographs are therefore much rarer.

Detailed view of the column wheel on our chronograph 910 SRS.

In our D3-System watches, the push-piece pins and crown shafts are mounted directly in a fine-finished case aperture, creating a perfect seal to the case.

In conventional designs, the push-piece pin and crown shaft are mounted in the case hole inside a tube insert. The required tube seal not only represents an additional potential source of gas diffusion (see Ar-Dehumidifying Technology), but careless handling can also lead to loss of water resistance with this design. This is because the push-piece pin and the crown shaft can bend in the tube if exposed to lateral knocks, permitting moisture to penetrate. This is a risk which also exists in screwable crowns and push-pieces when they are unscrewed to make an adjustment.

The D3-System permits the crown and push-piece to be integrated in the case, providing reliable protection from lateral knocks and the penetration of dust or moisture.

Section through a D3 push-piece.

D3 crown system with screw connection.

A composite material made of two different types of steel. The special characteristic of this material is brought out by surface etching, which reveals an organic pattern of light and dark stripes.
The etching patterns that are characteristic of Damascus steel highlight the stratified composition of the material, which is made up of at least two different types of steel. The separate layers of steel are forge-welded together to form a permanent bond. In the traditional process of manufacturing knives and swords, hard/brittle and softer/elastic types of steel were alternated to combine the respective benefits of resistance to breakage and edge retention. Nowadays, Damascus steel is primarily manufactured for its decorative charm and in appreciation of the forgery craftsmanship.

After a work piece has been welded, forged and hardened, the final step is surface etching to reveal the typical Damascus pattern. This is achieved in an acid bath, where the two types of steel demonstrate varying degrees of corrosion. The strata between the more resistant steel layers wear more quickly so that they become rough and take on a darker grey tone. This gives rise to the typical Damascus texture, which most resembles a wood grain, but can also take the form of more unusual patterns (when the material is twisted during forging, for example).

We decided to use a combination of stainless steels to produce the case material of our 1800 S DAMASZENER, with corrosion resistance almost as high as the other steels we use for our cases. To finish, the work pieces undergo our tried-and-tested TEGIMENT process. In this regard, the stainless steel composite resembles traditional (non-stainless, martensitic) Damascus steels, which are hardened using a heat treatment.

Another point to note is that the dial on our 1800 S DAMASZENER is not designed as a separate component, as is customary; instead, the dial and central part of the case are milled from a complete steel block. This means that the Damascus pattern on the dial continues across the entire case, creating an organic whole.

A composite material made of pure titanium and an ultra-strong titanium alloy.

In the style of classic Damascus steel, this special material is made by welding together alternate layers of Grade 2 pure titanium and Grade 5 titanium. There are, however, three major challenges associated with making a watch case out of Damascus titanium that are not an issue with Damascus steel – the processes of forging, etching and hardening the titanium material.

It is extremely difficult to forge Damascus titanium because it is made from two materials with very different strengths and fluidities. Pure titanium phases have a tendency to flow out of the ultra-strong titanium layers under the high pressure required for forging. This material oozes out of the sides and has to keep being removed between the individual forging stages. This adds to the amount of time required for forging and results in a low output of only around 50% of the original mass.

The etching process is also much more challenging with Damascus titanium than it is with Damascus steel. Steel can be etched using sulphuric acid, which is easy enough to work with. The same cannot be said for titanium since it is known for its high chemical resistance. Hydrofluoric acid (HF) – and serious precautionary measures – are required for etching Damascus titanium. Suitable etching parameters, such as temperature, duration, acid concentration and additive values, have to be calculated and monitored closely to ensure that the highly aggressive acid is only used for decorative etching and not chemical burning.

A pattern on an unhardened Damascus titanium surface can soon lose its appeal if lots of little scratches start interfering with the organic shapes. That is why it is necessary to harden the surface of Damascus materials. Sinn has developed a special TEGIMENT technology for titanium, with the full mass hardening process taking place internally.

We introduced a Damascus titanium watch case to our 1800 series in 2024. We wanted to highlight just how special this composite material is, so we made the dial an integral part of the bezel for this model. This means that the organic patterns on the dial flow seamlessly onto the bezel.

The deck watch – a portable watch with readability and precision tailored to navigational purposes.
The history of ‘B-Uhren’, or deck watches, began when they were first used as timekeeping equipment on ships.

Once it was possible to make watches that could provide sufficient accuracy at sea, the navigational determination of the longitude was based on the difference between the true local time astronomically determined on the ship and the time ‘taken along on the voyage’ from a harbour (this equated to the time at the harbour’s known longitude). The difference was determined by synchronising a marine chronometer permanently installed on the ship with the harbour time. Smaller, portable precision watches were therefore required for two reasons. Firstly, the precise harbour time had to be ‘transported’ from the nearest observatory to the marine chronometer. Secondly, to conduct astronomical observations at sea, the time on the marine chronometer had to be frequently compared with the time astronomically determined on deck. These tasks were performed by deck watches, which combined a high level of precision with clear readability and, above all, easy portability. The classic deck watch was similar in format to a pocket watch, but slightly larger. At sea, the deck watch would be set to the true local time once or twice a day by observing the sun or other celestial bodies, and the difference between this time and the time on the marine chronometer would then be used to calculate the longitude currently reached.

In the 20th century, a large number of deck watches were made for the military sector. In 1940, the Deutsche Wehrwirtschaftsamt (German Office of Military Economics) forced several well-known manufacturers to produce navigation wristwatches which had to fulfil special requirements established by the Reichsluftfahrtministerium (German Ministry of Aviation). Because the specifications included a narrowly defined model (the company name was not even allowed to feature on the dial), a standardised design emerged during this period. To this day, pilot and deck watches are still based on this historical standard design.

The watches had a standard diameter of 55 mm. From 1941 onwards, there was a prescribed dial pattern with a minute scale from 5 to 55 and an inner circle with an hour scale from 1 to 12. Instead of the ‘60 minute’ marker, this dial features an eye-catching triangle to make the watch’s orientation clear and ensure that it can be quickly and reliably read.

We select special pairs of materials that work together without lubrication (!) and without causing friction, ensuring long-term accuracy of the movement and particularly of the Swiss anchor escapement.

At the suggestion and with the help of Sinn Spezialuhren, TESTAF was used shortly after its completion by the German Institute for Standardisation to develop a new standard for pilot watches DIN 8330 "Timekeeping Technology - Pilot watches" for the first time.

A minute-clicking bezel which can only be rotated on one side to prevent accidental adjustment. It should also be possible to set a diver’s bezel when wearing gloves.

Besides the main marking (e.g. luminous triangle) there may also be a minutes scale running clockwise.

Watches specially built for diving which, in compliance with DIN, have to fulfill a range of requirements in addition to being water- and pressure-resistant.

Our diving watches meet the safety requirements and pass the tests stipulated in DIN 8306. This contains the following test criteria:

• Readability
• Accuracy
• Antimagnetism
• Shock-resistance
• Fastening elements
• Air tight under high pressure
• Saltwater resistance
• Scale setting ring or diver’s bezel
• Functional reliability of control features
• Functional reliability of diving watch under high water pressure
• Resilience to temperature stress
• Perfect functioning of crowns, push-pieces and similar control features
• Watertight under high water pressure
  

DNV provides technical testing and certification as well as software and independent advisory services to the energy, oil and gas, and maritime industries.

See Tests and Certifications:

A primary forming process that allows complex three-dimensional surface structures to be achieved with a high degree of precision.

As a primary forming process, electroforming starts with the production of a primary form – similar to the production of a gold mould for series jewellery production.
The most finely structured complex primary forms can be created – especially with the aid of modern laser technology.

The process enables the surface structure of the primary form to be produced with nanometre precision.
The respective number of plastic negative forms are derived from this primary form for producing the final product. This is achieved, for example, by using a plastic-injection-moulding process, whereby the primary form acts as a tool. While a complex production process used to be required to create the surface of the primary form, much less effort is now needed compared to original manufacture to reproduce expendable moulds. At 100 to 200 nanometres, the precision lost from turning the primary form into negative production forms is well below visually recognisable variations.
A major advantage of this process is thus the fact that there is no noticeable loss.
A thin film is applied – for example, using a PVD process – to the surface of the plastic negative form, making it conductive.

Electroplating is then used. The now conductive plastic forms are used as an anode in an electroplating process, whereby the cathode material (e.g. copper) separates from the surface of the plastic forms, slowly replenishing the negative form. The separated material thus becomes the final product.
The relief-forming composition of the final product produced during the electroplating process also faithfully renders the micro surface structure of the forms. Highly precise, metallic copies of the primary form are ultimately created from the cathode material.

Lastly, the plastic forms are then dissolved in chemicals and thus lost in the production process. The final product of the process is thus released. Decorative coatings can be applied to give the product a final finish.

The process is ideal for producing complex, finely structured relief dials. Above all, this offers the freedom to produce small partial areas with completely different micro surface properties, as the usual restrictions when using mechanical tools no longer apply.
The relief dial on our 1746 Heimat model was produced using the process described above. It thus exhibits highly defined details and differently structured detailed surfaces ranging from matt silk to polished. The final finish comes in the form of a thin layer of rhodium.

Thin layer of a perfluorinated plastic (e.g. Teflon) which is applied to certain parts of the escapement to prevent the watch oil from liquefying. An epilam coating is oil-repellent.

Sinn trademark: Used for Einsatzzeitmesser (Mission Timer).

The luminescence phenomenon exploited by daylight luminous paints.

Ordinary paints reflect some of the sunlight or artificial light falling upon them, making them visible to the human eye. In addition to simply reflecting light, daylight luminous paints, by contrast, also emit light, giving these paints their characteristic brightness. The effect is familiar from highlighter pens.

Fluorescent paints only emit this extra light when they are exposed to a light source. Tiny afterglow effects (lasting millionths of a second) which occur as a result of fluorescence cannot be perceived by the eye. By contrast, the luminous paints used to make the dials, hands or luminous triangle glow in the dark exploit the effect of phosphorescence.

A minute-clicking bezel which can only be rotated on one side to prevent accidental adjustment. It should also be possible to set a diver’s bezel when wearing gloves.

Besides the main marking (e.g. luminous triangle) there may also be a minutes scale running clockwise.

Goldbronze 125 (CuSn7Au12.5) is a bronze alloy developed and patented by Sinn. The gold bronze produced in a multi-stage alloy process has an exceptionally high degree of purity.

Classic bronze is a copper-tin alloy (e.g. CuSn8), which is supplemented with a wide range of additives. In Goldbronze 125, common admixtures and impurities such as lead, cadmium and nickel, which are permitted in DIN EN 12163 for copper-tin alloys, are below the detection limit of 0.002%. For nickel, for example, the content is 100 times lower than the permissible standard value of the classic bronze CuSn8.

Compared to conventional bronze alloys, the special degree of purity results in improved skin compatibility and increased corrosion resistance to seawater. The tendency toward chemical reactions in the case of non-magnetic Goldbronze 125 is counteracted by an alloyed gold finish. Goldbronze 125 continues to develop a darkening of the surface due to oxidation, also known as a patina. However, the alloy achieves a higher degree of inertness in the face of environmental influences than ordinary bronze (CuSn8) because it has gold as a component. If desired, the mentioned darkening of the surface can be removed with a gold bronze cleaning cloth provided that the oxidation is minimal enough.

Goldbronze 125 is a registered trademark.

We use our Goldbronze 125 for our T50 GBDR and T50 GOLD BRONZE models.

A spiral-shaped, coiled, flat wire which, together with the balance, forms the oscillation system of a mechanical wristwatch. Modern wristwatches generally contain flat coils with 12 to 15 windings, i.e. all the coils are in a single plane. In addition, most hairsprings are made of a metallic alloy called Nivarox.

The hairspring is fixed to the rotation axis of the balance and provides the decelerating and accelerating forces required to make the balance wheel oscillate evenly to and fro. The energy lost through friction is applied in pulses by the escapement.

Hairspring (here Breguet overcoil).

Thin layer of a perfluorinated plastic (e.g. Teflon) which is applied to certain parts of the escapement to prevent the watch oil from liquefying. An epilam coating is oil-repellent.

Absolutely free from fogging, pressure-resistant at any accessible diving depth and perfect readability from any angle under water – these are the unbeatable advantages of our diving watches equipped with HYDRO Technology.

See Sinn Technology HYDRO

Sub-scale on mechanical altimeters in aircraft for calibration purposes.

There are two methods available in modern flight operations to determine the flight altitude: radio altimeters and barometric altimeters. Barometric altitude measurement is based on the dependence of static atmospheric pressure on sea level. The higher the flight altitude, the lower the air pressure there. There are various calculation models for the exact relationship, whereby the altimeters are based on the international standard atmosphere (ISA).

A barometric pressure gauge can therefore be used on this basis to measure the flight altitude without any electronic means by displaying the air pressure directly as the flight altitude using a suitable scale. With this method, however, it should be noted that the air pressure also depends on the weather conditions (high and low pressure areas). To counteract this error, barometric altimeters have the option of manually setting the current local air pressure and calibrating the altimeter with it. This also shifts the main display of the device. This current air pressure setting appears in a small window that is integrated into the main display, comparable to a 3 o'clock calendar window on a wristwatch. This so-called Kollsman window is cut out a little more generously than a conventional calendar window and allows a view of a small angle range of pressure settings.

A unit of length by which the diameter of Swiss movements has traditionally been and still is measured.

The ‘line’ as a unit of length was introduced to Swiss watchmaking as the ‘Paris line’, a French unit of measurement, for the purposes of documentation in the context of the international watch trade. It has been used as the traditional unit of measurement for movement diameters ever since.

A ‘line’ is 2.256 mm.

Lug width:

This term refers to the width of the strap at the point where it is fitted to the watch - more precisely, at the so-called lugs. The lug width is crucial as it determines which watch models are compatible with a strap. For example, a watch with a lug width of 20 mm requires a leather strap with exactly this lug width.

Buckle width:

In contrast, the buckle width refers to the width of the strap at the buckle. Precision is also crucial here, as the buckle width determines which clasp can be fitted to the strap. It is important that the buckle width of the strap corresponds exactly to the width of the buckle itself to ensure smooth integration. A pin buckle with a width of 18 mm therefore requires a strap with a buckle width of 18 mm.

A coating for watch dials and hands, enabling them to be read in the dark.

In the past the main luminous paint used was radioactive tritium (³H). Today inactive luminous paints such as Superluminova are used almost exclusively. These are charged by the incidence of light and exhibit a temporary luminous effect (phosphorescence). Daylight luminous paints (fluorescence) are used in individual cases (e.g. EZM 10 TESTAF).

The luminosity time and intensity that can be perceived from luminous paint coatings depends of numerous factors. On the product-side, these include the charging status, type, and concentration, as well as the body colour of the luminous pigments, the luminous paint as well as the design-and-function-dependent surface areas and coating thicknesses. Furthermore, personal perception depends on eye sensitivity and the individual’s potential to adjust to the ambient light. Based on the large number of determinants, it is not possible to make general statements on how the temporary luminous effects of coated surfaces are subjectively perceived.

However, special attention should be paid to the colour point of the luminous pigments in our series. The body colours that we use for the luminous pigments are white, light green, ivory and black. As a general rule, dark-coloured luminous pigments produce a lower-quality temporary luminous effect (intensity and luminosity time).

For example, with the U1 series, this is demonstrated as follows:

Left: white luminescent colour. Right: black luminescent colour.

The night views shown in the SINN online shop show neither the light intensity nor the exact colouring. They are simply intended to illustrate those parts of the watch which are coated with luminescent colour.

Watch case which shields against magnetic fields.

Mission Timers (Einsatzzeitmesser or EZM) are watches which have been specially developed for a particular purpose. They always offer excellent readability. This means: the form is always dictated by the function and handling requirements.

The legendary EZM1 was the first in a successful line of mission timers.

Sinn trademark, standing for navigation cockpit clocks. Navigation cockpit clocks are intended for installation in aircraft cockpits.

Chemical element: a hard, silver-white metal obtained primarily from magnetic pyrites.

Nickel is an important alloy component in many types of steel. The nickel content in these is between 9 and 18%. Nickel steel is exceptionally hard and robust. It is used for tools and for military purposes (armor plate, gun barrels). Combined with chromium it produces highly corrosion-resistant chromium-nickel steel.

Some people have an allergic reaction to it if it comes in contact with their skin.

An alloy made of copper, nickel and zinc.

This material has been dubbed ‘nickel silver’ due to its silvery appearance. It does not contain any silver, but has been purposely developed to look like silver.

Nickel silver is an excellent material, characterised by high strength and corrosion resistance. It is traditionally used to make instruments, cutlery and precision equipment.

The term ‘pilot watch’ is used in literature and by watch manufacturers in an inconsistent and unclear way. The general understanding is that a pilot watch is characterised by certain traditional design features such as a black-and-white dial with a striking, triangular 12 o’clock marking.

At SINN, too, we provide the clearest possible readability for pilot watches. In addition, the sapphire crystal watch glass in all SINN pilot watches must be capable of withstanding negative pressure of up to 0.2 bar. This corresponds to a flying altitude of approx. 12,000 metres.

Together with SINN, the flight lab at Aachen University of Applied Sciences launched a technical standard (TESTAF) for the professional use of wristwatches in aviation, which contains a precise list of requirements and sets out an appropriate certification procedure.

The first watches to be TESTAF-certified were the SINN chronographs EZM10 TESTAF, 103 Ti UTC TESTAF, 103 Ti TESTAF. The pilot watches 857 UTC TESTAF and 857 UTC TESTAF LH Cargo followed in 2013, and the EZM 9 TESTAF in 2014.

At the suggestion, and with the cooperation, of Sinn Spezialuhren, the TESTAF standard was used by the Deutsches Institut für Normung (German Institute for Standardisation) shortly after its completion as the basis for the development of the first standard for pilot watches (DIN 8330-1/8330-2).

The pulsimeter or respiration scale is a scale with a base of 15. It permits pulse or breathing rates to be read off after stopping the time required for 15 pulses or breaths. For example: 15 heartbeats in ten seconds equals a pulse rate of 90 beats per minute; or 15 breaths in 36 seconds represents a respiration rate of 25 breaths per minute. This procedure can also be used to determine other units on a per-minute basis. Simply measure the time needed for 15 units, and then read off the units per minute.

Combination of a tachymeter/pulsometer scale on a 144 St DIAPAL watch

A registered trademark of Sinn Spezialuhren which refers to a uniquely shaped second display.

In the case of the EZM 12 model – the mission timer developed in collaboration with the emergency doctors of the air rescue team – the pulse rotor display features a four-arm second hand.
The rotor blades of a helicopter served as the inspiration for the design. The cross-shaped arrangement of the four hand elements facilitates faster, hands-free checking of a pulse. You can begin checking a pulse every 15 seconds using the central second hand of the 12-hour index without the need for hands and without activating a watch control.

Watch equipped with a quartz movement.

Quartz watches were developed and built for the first time in the first quarter of the 20th century. Based on a more affordable production technology, they conquered the market in the late 1970s.
While you can actually observe the clockwork mechanism of a watch in action, the function of a quartz watch is based on electronic processes which, for the most part, are not directly visible. While the physical oscillation of the timepiece is also visible in the centre of the quartz movement – that is, the oscillating crystal – this oscillation is so slight and so fast that it is invisible to the naked eye. What’s more, the oscillating crystal is positioned inside a capsule, which allows it to oscillate shielded in a protective gas.
The basic principle behind quartz oscillation is the (inverse) piezo effect, which refers to the visible formation of crystals in many materials following the application of an electric charge. Inside the movement, such a piezoelectric element is integrated into an electronic oscillator, which generally operates at a frequency of just over 32,000 Hz. Through continued frequency division, the second interval is derived from this high frequency, ultimately actuating the stepper motor. In the case of analogue quartz watches, the stepper motor generates the typical jerking movement of the second hand using the gear train.

Due to their high frequency, quartz movements are much more precise than mechanical movements. Unlike temperature-compensated chronometer movements, conventional movements demonstrate a deviation of a few seconds per week. They are dependent on electrical energy to function. This energy supply is usually guaranteed for approx. 2 years with the most common button cells. As with mechanical movements, however, there are special designs of quartz movements that draw their energy from a barrel or an oscillating weight. Lithium batteries and particularly energy-saving motors also provide significantly longer lifetimes. Our UX and U50 HYDRO models are each equipped with at least one of these measures.

Complications, chronographs and perpetual calendars can be incorporated into quartz watches without much effort, as the corresponding displays are powered by separate motors and the associated controls are easy to program using the integrated circuits.

Column wheel chronograph.

A device used to set the rate of a watch.

Regulator device mounted on balance cock.

A regulator correction changes the effective spring length of the oscillation system’s hairspring. Before the hairspring hits its outer fixture point it passes through a gap formed by two adjacent pins. The part of the spring between the gap and the outer fixture point is exempted from the free oscillation of the spring. If the position of the gap is shifted by a regulator correction, this changes the active spring length. Depending on the direction of the change, the watch then runs faster or slower.

A chemical element belonging to the group of platinum metals.

Rhodium is a precious metal that is difficult to extract, and is comparable to platinum in many respects. Jewellery designers often use rhodium to give white-gold alloys a decorative finish.

The surface of the relief dial of our 1746 Heimat is rhodium-plated, which gives it a bright, silvery sheen.

See Sinn Technology Captive Safety Bezel.

Section through flat sapphire crystal.

The blank of a single-dome sapphire crystal watch glass needs to be thicker than the final glass thickness. However, the final shape of the crystal is only formed from a single dome radius, meaning that the grinding process is still relatively simple.

Section through domed sapphire crystal.

A domed sapphire crystal watch glass for our series 356 and 358 recreates the form of the acrylic glass, using five different curvature radii. For this reason, grinding tools which have been specially made for the specified radii are needed to create the inner and outer form of the dome.

Das hochgewölbte Saphirkristallglas der Modellreihen 356 und 358.

The thickness of the sapphire crystal glass blank for our series 356 and 358 is roughly 5 mm, i.e. it is much thicker than the blank for a conventional flat glass. The final shape must first be ground out of this blank and then carefully polished.

Blank for sapphire crystal glass with indication of final watch glass.

See balance.

Fully synthetic grease developed especially for SINN for use on seal rings at temperatures ranging between -45°C and +80°C.

A seal ring treated with this grease has a considerably lower gas permeability rate than an ungreased ring at the same compression and temperature. It also increases the ageing resistance of the seals.

The performance of EDR seals is optimized through the use of Sinn sealing grease 30-288. This combination gives Sinn watches significantly greater protection against humidity than any conventionally sealed watch.

High-grade, fully synthetic oil specially developed for Sinn. Its outstanding properties at low and high temperatures allow the watch to run accurately from -45°C to +80°C.

The slide-rule scale works on the principle of logarithmic scale divisions. This allows you to multiply and divide numbers. It is useful for calculating consumption, converting units and currencies and for all kinds of rule-of-three calculations.

An additional second hand on a stopwatch/chronograph for recording intermediate times.

With a split-seconds chronograph (also called a rattrapante), two second hands are set in motion when the start button is pressed. The specific split-seconds function now makes it possible to stop the second stopwatch hand (the ‘carried’ hand) separately, without affecting the movement of the other second hand. In this way, an intermediate time can be recorded. The split-seconds hand can be re-synchronised with the first second hand by pressing the intermediate stop button again.

Our 910 Anniversary model features this special function.

An abbreviation used to indicate a fly-back function on SINN chronographs.

Pilots or athletes are often faced with the challenge of measuring or specifying the lengths of several immediately consecutive time intervals separately (i.e. not aggregating them). A pilot may have to fly in a certain direction for 20 seconds and then change course for 45 seconds, for example. To accomplish this measuring task with a normal chronograph, they would have to stop the time measurement after 20 seconds, reset the timer to zero and start measuring 45 seconds from scratch. This not only means pushing a button three times, which is quite laborious, it also creates a gap between the end of the first and start of the second measurement that is equivalent to the length of time taken to push said button. By contrast, the SRS function means you can push the reset button to trigger all three functions at once – stop the current measurement, reset the timer and start the new measurement. In visual terms, this specifically means that pressing the button once resets the running second stopwatch hand to zero without interrupting the measurement. People also talk about a ‘reset in flight’, from which the traditional term ‘flyback’ is derived.

Our 910 SRS is equipped with this function.

Name of in-house movement modifications.

The SZ01 movement has been specially developed by SINN. The development work began back in 2003.

The SZ01 is used in the 717 model.

The main priority in undertaking the redesign was to make the chronograph functions significantly easier to read off. Which is why we attached so much importance to finding a first-class technical solution to mounting the jump 60-minute stopwatch hand in the centre of the dial. This allows users to take accurate stop times even more quickly and simply. The clarity and distinct readability of this chronograph stem from the design of the well-known Lemania 5100 movement.

Our redesign enhances the readability in two ways: firstly, 60 minutes are now counted in one sweep of the hand instead of the usual 30 minutes, and secondly, the minute stop scale covers the entire diameter of the dial.

The SZ caliber 02 is a in-house modification of the SZ01 movement, characterized by an off-center 60-minute counter.

The SZ02 is used in the EZM 13.1 model.

Usually, the counting minute of the chronograph function only has a 30-minute counter. Stopped times are difficult to see on these standard calibers as the interim marks of the hour counter are very close to the hour indices. Only with the aid of this pointer is it possible to distinguish between a minute display of 0 to 30 and 30 to 60. The SZ02 permits direct reading of the minutes right through from 0 to 60 minutes.

The SZ02 was launched in 2006, the year of the World Cup in Germany. It was housed in the case of the 303 football chronograph. The caliber has more than proved its worth since then, forming a reliable base for the perfect readability of the diving watch EZM 13.1.

The SZ03 is developed by Sinn and is characterised by a calendar week display at six o’clock.

In addition, the movement displays the date, the day of the week and the month.

Sinn’s own rebuild of the Unitas 6498 pocket watch caliber into a movement with regulator display.

The REGULATEUR 6100 was the first watch in which the SZ04 was used.

A regulator pointer recalls a feature found in precision grandfather clocks, which have a large-diameter fine-minutes dial for regulatory or monitoring purposes. For reasons of better readability in the minute hand, this features small, off-center hour and second dials.

Sinn has moved the hour dial from the center towards 12 o’clock, without causing any additional friction losses or using additional gearing. The Unitas 6498 caliber already had a small seconds dial, and the SZ04 represents the optimum horological solution of a regulator display with three separately positioned dials for hours, minutes and seconds.

The SZ05 is used in the 936 model.

The purpose of the in-house movement redesign was to significantly increase the clarity and readability of the dial display. To this end, in designing the SZ05 we focused on a stopwatch minute display with a 60-minute scale at 3 o’clock and a running second hand at 9 o’clock. This does away with the annoying necessity of adding stopwatch minutes as required with conventional 30-minute stopwatch displays.

The SZ06 is a chronograph developed by SINN.

The SZ06 is first realized on our series 6012.

It combines the decentralised 60-minute counter (SZ02) with a moon-phase indicator and a full calendar.

The tachymeter scale permits an average speed to be measured over a distance of one kilometer. For this, the stop-watch function must be activated at the start and end of the distance. Miles per hour (mph) can also be measured using the tachymeter scale and the same principle.

A tachymeter scale shown on a 956 Classic watch.

SINN trademark for stainless steel and titanium surfaces with a particularly high level of hardness and scratch resistance. SINN watches featuring this technology have been labelled with the TEGIMENT logotype since 2008.

See Sinn Technology Temperature Resistance Technology.

TESTAF is an acronym for ‘Technischer Standard Fliegeruhren’ (technical standard for pilot watches), a list of requirements and the creation of a certification body for watches launched by the Department of Aerospace Technology at Aachen University of Applied Sciences together with Sinn Spezialuhren which is used in professional aviation operations.

TESTAF

Technischer Standard

Fliegeruhren

At the suggestion and with the help of Sinn Spezialuhren, TESTAF was used shortly after its completion by the German Institute for Standardisation as a basis on which to develop a standard for pilot watches (DIN 8330-1/8330-2) for the first time. TESTAF can be viewed or downloaded free of charge at www.testaf.org.

Distribution of the DIN standard is strictly prohibited by copyright law. The standard may only be purchased from the Beuth Verlag publishing house as a document for download or in paper form.

Sinn only uses titanium grade 2 and titanium grade 5, which is an ideal material for wristwatches.

No allergic reactions are known. With a specific weight of roughly 4.5 g/ccm it has just 60% of the weight of stainless steel (specific weight approximately 7.8 g/ccm). It quickly absorbs body heat as a result of its low specific thermal capacity and its low thermal conductivity. This makes it comfortable to wear, particularly during the cold months of the year. The low electrical conductivity of titanium also increases wearing comfort as it reduces the electrical voltage compensation between different parts of the skin around the wrist.

Grade 2 titanium: pure titanium with the material number 3.7035.

Grade 5 titanium: a high-strength titanium alloy with the material number 3.7165.

A radioactive luminous paint for dials and hands.

Tritium is an isotope of hydrogen (³H), a volatile gas. It is slightly radioactive and has a half-life of 12.3 years.

Luminous paint which is energised by tritium does not need to be charged by external light. The volatile gas is bonded in a polymer (tritiated plastic). With its electron radiation, it energises a passive luminous substance such as zinc sulphide, causing it to emit visible light.

The radioactivity emanating from the tritium coating in a water-resistant watch covered with a sapphire crystal is not detectable. Luminous paints containing radioactive tritium are completely harmless to wearers of watches.

If a Sinn watch is labeled water-resistant, it fulfils the requirements of DIN 8310 in its original specifications. Sinn guarantees that its water-resistant watches can withstand pressures up to at least 10 bar. This corresponds to the pressure at a depth of 100 m. Some of our classic masterpiece models are exempt from this. The water-resistance of each individual watch we produce is checked. The maximum depth given on many watches always refers to the maximum static compressive stress which the watch case is guaranteed to withstand. When swimming, or in a jet of water (washing hands or showering), there are also directional flows with dynamic pressure peaks which impact upon the relevant parts of a watch to a greater extent than the diving depth alone.

In order to use a watch safely when swimming we therefore recommend a compression resistance of at least 100 m. Diving watches are recommended for intensive and frequent use in water. The compressive resistance of a diving watch is given in bar or in depth, measured in meters. When diving, the pressure increases by one bar every 10 m.

In everyday use it is important to note that seals can suffer from wear or ageing and that small direct particles can build up in them as the result of a wide range of factors which arise when wearing a wristwatch. These particles can themselves assume a part of the seal function if the seal elements are already suffering from extensive wear. Tensides from detergents or similar cleaning agents can then coat such particles, making it easy from them to be washed away.

For these reasons the airtightness of a wristwatch should be checked on a regular basis (once per year).

For smartwatches, statements about water resistance usually refer to the so-called IP protection classes. The distinctions between these protection classes are used in electrical engineering to describe cases for ‘electrical equipment’ in terms of the protection they offer against water and dust and to enable this protection to be verified. The associated standard is DIN EN 60529.

Because this approach treats a watch as a piece of electrical operating equipment, the requirements and testing methods are not specific to wristwatch cases but have to be applicable to any protective case. The disadvantage of this is illustrated by the following example.

The protection class most commonly found with electronic watches is IP 67 (which corresponds to DIN EN 60529). The first digit, 6, indicates how dust-proof the case is. The second digit, 7, is determined by a water resistance test which, at first glance, corresponds exactly to the ‘designated stress’ for wristwatches as per DIN 8310 (water resistance): the device is immersed in water at a depth of 1 m for 30 minutes. But while DIN 8310 includes several sub-tests to ensure that the case is equipped to withstand this stress, the IP protection class test is limited to the immersion of the device in water at a depth of 1 m for 30 minutes. The reason for this difference is that DIN 8310 wants to test the case’s ability to withstand repeated immersion for short periods of time in shallower water depths, whereas IP 67 describes a one-off test process with the same situation.

To this end, DIN 8310 includes more stringent sub-tests than what is specified in its ‘designated stress’ section. Thus, the watch is exposed for five minutes to water pressure of 3 bar, which equates to a water depth of around 30 metres. To comply with DIN 8310, the watch also has to be exposed to a level of compressive stress 30 times higher than that of protection class test IP 67.

With DIN 8310, the watch is also immersed for 60 minutes in a water depth of 10 cm. So after the watch’s stability at a water depth of 30 m has been guaranteed, it is tested at very low pressure at a depth of 10 cm. When the case is immersed in shallow water, the seals are no longer being pressed against the sealing surfaces on the case as they are at higher pressure. This means that the seals have to be able to withstand capillary splitting effects themselves, using their own inbuilt compression.

Furthermore, DIN 8310 checks for any water that might have penetrated the case using a condensed water test (whereby water that has penetrated the case is vaporised via exposure to heat, causing condensation to form on the cooled crystal). In this way, even very small quantities of water can be detected because they form a thin layer of condensation on the crystal. In DIN EN 60529, by contrast, this test criterion (the amount of water permitted to penetrate the case) is expressly left open and is subject to the jurisdiction of a Technical Committee responsible for the specific product. If there is no additional information available for these test criteria for a watch tested using protection class IP 67, then the labelling of that watch as IP 67 is not really very meaningful.

Overall, therefore, it is clear that the watch-specific DIN standard has significantly more stringent requirements when it comes to the word ‘water-resistant’ than protection class IP 67.

Zirconium-oxide ceramics
Technical ceramics that are made from the oxide of the metallic element ‘zirconium’ using a sintering process. The precise chemical name is zirconium dioxide. This raw material belongs to the group of oxide ceramics which also includes aluminium oxide, known in watchmaking through (polycrystalline) sapphire glass and rubies.

The term ‘ceramics’ is generally understood to be a much narrower term than the one used today in technical contexts. Whilst people mostly think of clay and porcelain products – i.e. special silicate ceramics – when ceramics are mentioned, they have also long been widely used in technology such as in ball bearings, plain bearings or engine parts. First amongst the modern types of ceramics used here is zirconium oxide. Whereas conventional ceramics dating back far into the annals of history can be produced from natural raw materials and at relatively low firing temperatures, the technical ceramics introduced over the last 100 years only obtain their special properties by using high-purity synthetic starting materials and applying high temperatures and pressures.

Beginning with a very fine powder (less than 1 micron particle diameter), a sintering process is used to produce zirconium ceramics, just like in the production of traditional ceramics. The temperatures almost reach the melting point of the ceramic powder and induce the fine powder particles to cake. This sintering process is combined with the ‘hot isostatic pressing’ process in the production of technical zirconium ceramics, where it is fired under high pressure (acting from all sides) to produce a significantly thicker material with much finer crystals, as opposed to traditional firing technology. Among the resulting properties of this material, the main ones are:

• high heat resistance, low thermal expansion
• non-conductive
• biocompatibility
• high corrosion resistance
• high hardness levels with equally high levels of mechanical strength

The two latter points make the materials very attractive to watchmakers. Zirconium oxide ceramics are characterised by very high resistance to scratches, but at the same time they have a mechanical strength that is more than double that of sapphire glass. This means that zirconium ceramics are not prone to breakage despite their high hardness level.

By adding coloured particles, the naturally white zirconium dioxide can take on a black or coloured appearance.