Watch oil

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Swiss watch oil in vials with outer packaging

Watch oils are lubricating oils that are specially selected, developed and used for watches . They are also used in precision engineering for sliding pairs that are comparable to those of a watch, for example in measuring devices , cameras and film cameras .

Requirements and properties of the lubrication points

The lubrication points with their sliding pairs in a watch have very different requirements. Both the bearing pressures and the friction speeds can move within a very wide range. They can also be made of various materials, such as brass, steel, plastics and stones . The rubbing points must be differentiated into radial bearings , axial bearings , interventions, slideways and friction points in wound tension springs. This means that a watch usually has to use several different oils. The watch manufacturer specifies which oil or grease is used where in a lubrication plan .

Particular problems with lubricating watches

Since many clockworks and the corresponding lubrication points can also be very small, they only take up very small amounts of oil (sometimes only fractions of 1 µl). A major problem is that the oil binds dust, abrasion from the sliding pairs and oxides of the materials used. With the small dimensions of some watches, their "delicate" structure and the required precision of time measurement, even tiny dirt particles can thicken the oil so that a pair of bearings blocks and the watch stops. Countermeasures are very clean working, the most dust-proof design of the watch, low-wear sliding pairs (stone bearings) and low-corrosion materials (which is why steel and brass parts are occasionally gold-plated).

Oils should only get there where lubrication is absolutely necessary. Since oils run ( spreading ), they can leave the lubrication point, after which it runs dry. Usually, the tendency to run increases with the amount of oil in a bearing. This problem is countered by oiling sparingly, applying an oil depression in bearings, a certain viscosity , a high surface tension of the oil and a surface treatment of parts to be wetted ( epilamization ).

Historical development

In the past, selection and use were based on the one hand on the offer and on the other hand on the watchmaker's experience. A few vegetable oils (e.g. castor oil ) were in use, but also many oils of animal origin, e.g. B. bone oil . Fish oils (mainly from bottlenose dolphins ) were also used in the USA . Most of these oils met the requirements listed above, but had the serious disadvantage of gumming up under the influence of light and atmospheric oxygen, so that the bearings stick together after a few years.

The next generation of watch oils were mineral oils that were significantly less susceptible to gumming and becoming rancid . However, the lubricating properties compared to the vegetable oils were often rated worse.

Today synthetic oils and semi-synthetic oils are used, which are protected against aging.

Classification of watch oils

Watch oils are differentiated according to type. The grades accordingly range from 1 to 5 with increasing viscosity. Type 1 is a low-viscosity oil that is suitable for very small, faster-running, low-force sliding pairs of smaller watches. These are, for example, the pairings of the balance wheel, the armature and the steering wheel as well as the journal bearings of the second and third wheel. Grade 5 is an oil for large clockworks or low-speed bearings with great forces such as the barrel and mainspring.

Today, universal oils are often offered that cover several types, for example types 1–3 and types 3–5.

See also

literature

  • C. Zerbe (Ed.): Mineral oils and related products. A manual for laboratories and operations, 2nd edition, Springer, Berlin / Heidelberg 1969, ISBN 3-642-87510-6 .
  • Hermann Hager (Ed.): Central Pharmaceutical Hall for Germany. Volume 7, Volume VII, Hager, Berlin 1866, pp. 268–270.
  • German watchmaker newspaper. Volume 38, Carl Marfels, 1914, pp. 78-79 and 108.
  • Richard Ascher: The lubricants, their type. Testing and use. A guide for the business man, 2nd edition, published by Julius Springer, Berlin 1931, pp. 264, 268.
  • Georg Heinz Göttner: Introduction to lubrication technology. Volume 2: Basics - Connections - Applications , K. Marklein, 1966, p. 132.

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