Why are jewels used in automatic watches

This is why it is harmful to insert the axis of such a wheel directly in the main-plate of the movement — considering the metal-vs-metal friction.

Even with modern lubricants, the axis can slow down the movement of the wheels — ruining the accuracy of the watch — and at some point, wheels will simply get blocked.

The solution — jewel bearings, which allow low friction with metal pivots. They also possess excellent temperature stability and are acid-resistant. The pivots and jewel bearings of the balance wheel are especially fragile and would often get damaged under impact.

They were a major cause of repair. With anti-shock systems, the jewels are mounted on springs allowing them to shift in their setting, in order to absorb radial or axial shocks. Incabloc, Kif or Etachoc are the more common shock protection systems for Swiss movements. The jewels are shaped so that the capillary action of the oil causes it to be drawn towards the gear axles instead of spreading all over. Very complicated watches can have over 40 functional jewels.

In conclusion, jewels ensure that a watch can function for longer periods until it requires servicing, and that the damage to high wear-and-tear points is greatly reduced.

It is worth noting that some brands have brought back the use of chatons — a difficult technique where small brass or gold settings are used to fit the jewel into the movement plate — and in some watches the setting of jewels is almost an art form.

Watch collectors are less interested in jewels today as they are now easy to include and are produced from synthetic materials. View all. Carl F.

Your email address will not be published. Sign up for email alerts. Home Our Watches. What do jewels in a mechanical watch mean? Tags 17 jewels , jewels , jewels in watches. Why to Wind an Automatic Watch by Hand? October 03, Clockmaking in London, at the beginning of the eighteenth century was recognised as a trade more akin to science than to metalworking; clockmakers were given their own company by Royal Charter, granted by King Charles 1, in Equally, London was a hive of scientific and industrial activity.

The necessity of profitable trade required a solution to the longitude problem. With increasing evidence in favour of the need for timekeeping to measure the distance from a given location on earth, there was a need to develop a clock or watch mechanism that was both accurate and consistent. We all know it was Harrison who eventually cracked longitude, but before he set to work on his groundbreaking clocks, the basic problem of consistency needed to be addressed.

Into the fervent world of real life problems and necessary solutions in mathematics walked a young mathematician from Switzerland, ironically enough: one Nicolas Fatio de Duillier. For those who may not recognise the name, de Duillier was the very close companion of one Sir Issac Newton.

He had fallen out of favour with Newton, however, and was looking for other means to make money. De Duillier proposed that jewels, with accurate and precisely drilled holes, could provide a means of holding pivots and allowing wheels to turn with less friction and more consistency. Mounting the jewels was not the problem; it was the second problem that required a solution. To drill such small holes in gemstones required a diamond drill; in the s de Duillier had perfected a method for doing just that.

The new patent was not just for jewels in watches but would have extended to any use within watches, including endstones and for bearings for pivots. Any watch made by any of the Clockmakers Company would then require a license to use gemstones in the manner specified by the patent. The number of rubies used in a mechanical watch varies depending on the complexity of the movement. The more moving parts there are, the more rubies are used.

A typical fully jeweled time-only watch has 17 jewels, but watches can have many more than this. Recently, on a trip to Piaget's manufacture, I had the rare — and very disconcerting — opportunity to try my hand at setting the miniscule rubies into the designated movement holes. Using tiny tweezers and a microscope, I proceeded to drop a ruby, flick a ruby and eventually get a ruby into its designated spot — upside down!