Particularly in the case of exclusive and complicated models, lubrication calls for a great deal of patience, manual dexterity and experience. The wire tip of the oil dispenser that Hansjörg Kittlas carefully introduces into a small container is less than 0.1 millimetres thick. With a steady hand, he deposits a drop of oil into the recess of a bearing jewel on the IWC-manufactured 94900 calibre. The drop is so tiny as to be virtually invisible to the naked eye. A single thousandth of a millilitre is enough to lubricate the entire watch movement. A fast sports car, on the other hand, gobbles up engine oil by the litre.
In another respect, too, a watch movement differs starkly from a car engine. While the engine speed of a performance car driven to the limit can top 8000 rpm, a watch movement is much more leisurely. The fastest-moving gear, the escape wheel, revolves at a rate of just 20 times per minute. “The speed may be relatively low, but the surface pressures are extremely high,” is how Kittlas describes the conditions in a wristwatch. It’s rather like a woman’s stilettos: the more pointed the heels, the deeper the impressions they leave in your parquet floor. The load exerted on bearings by pivots that are often just a few tenths of a millimetre thick is equally extreme.
The special conditions demand that a watch oil has to satisfy a number of equally special criteria. Up until the end of the first quarter of the last century, the lubricant of choice was neat’s-foot oil, which is extracted by boiling the fat glands in the feet of cattle. Its main disadvantage is that it rapidly deteriorates with age. A little over 50 years ago, the speciality chemical industry started developing synthetic watch oils with specific properties. Expensive high-tech products like these do not thicken or evaporate, even after long periods of time, and are resistant to both corrosion and oxidation.