Jewelled Watch Movements: Basic Information

Have you ever wondered exactly what is meant by the term ‘jeweled watch movements’? Before cheap quartz watches were manufactured, the number of jewels was one of the important factors by which you could assess the quality of a mechanical watch. This did not necessarily mean that the more jewels a watch movement had, the better it was – although watch manufacturers certainly did use the number of jewels as a marketing ploy. Two Waltham watches, one with a 100 jewel watch movement and the other with a 75 jewel watch movement were among the watches with the highest number of jewels ever made, but as you will see, this extraordinary number of jewels in the watch movements did not add to (or detract) from  the quality of the watches.

When watches and clocks were first manufactured, one of the problems faced by watchmakers was the fact that friction in the moving parts of timepieces affected timekeeping accuracy. Bearings made of hard material reduced this friction, allowing for more accurate timekeeping and also extending the life of the watch or clock. At the time, sapphires and rubies were the hardest known materials that could be cut. Although these jewel bearings were first used in watches around 1702, up until the middle of the 19^th century, most watch movements used hardened metal bushings, meaning that over time friction caused the watch movement to stop functioning.

The hardness and the slick surface of jewels such as rubies and sapphires made them much more effective for use in watch movements than steel brushings. Originally, jewel bearings in better quality watches were made of natural sapphires and (mostly) rubies that were cut by hand (using diamond powder) into tiny flat cylinders into which minuscule holes were drilled. Less expensive watches used garnet and quartz bearings. Following the invention of growing artificial sapphire crystals in 1902, synthetic rubies, which now cost about $0.02 each, replaced natural jewels in watch movements.

Jewels were used in watch movements because they had a function (acting as bearings for wheel trains, escape levers and other high-wear watch movement components parts). The tiny synthetic jewel bearings were set between the gears to reduce friction caused by the high load and speed motions of watch movement parts.The ticking sounds made by the jeweled movements of mechanical watches are nothing but the sound of the rubies (or other synthetic jewels) knocking against the steel teeth of the escapement wheel.

Lower-end jeweled mechanical watch movements usually had 5 or 7 jewels. Today these cheaper versions have for the most part been replaced by quartz watches, and the ‘fully jeweled’ manual wind watch movements that are still manufactured today contain 17 jewels that are functional. If the watch is a superior quality one, or one that has an extra thin movement, the manufacturer may add more jewels, bringing the total up to about 23. Automatic watches also need more jewels (between 4 and 8 additional jewels). The more moving mechanical parts (chronographs, calendars etc.) a watch movement has, the more rubies it may need to reduce friction. So, while more jewels could be an indication of a more complicated movement, a higher jewel count does not necessarily mean the watch quality is better; what matters is how the jewels are used.

It’s important to know that many watch manufacturers used jewel count as a marketing ploy, adding jewels that had absolutely no useful function to watch movements. This practice reached its peak in the 1960s.  As a result, in 1974 the International Organization for Standardization (ISO), in collaboration with the Swiss watch industry standards organization NIHS: Normes de l’Industrie Horlogère Suisse, published the ISO 1112, forbidding watchmakers from including nonfunctional jewels in the jewel counts they advertised.

The ISO standard has not succeeded in controlling the practice of ‘up-jewelling’ however and many experts agree that some manufacturers exploit loopholes in the ISO 1112 to continue adding to the jewel count of their watches. Pseudo-functional jeweled bearings are added to moving parts of watch movements that can work perfectly well without them. The purpose of these additional jewels is to persuade the consumer that the watch id of higher quality – when in reality they neither improve the functioning of the watch nor increase its longevity. The Waltham 100 jewel watch actually had a standard 17 jewel movement. The additional 83 jewels were mounted around the automatic winding rotor (they were totally nonfunctional and never contacted any moving parts of the watch).

In conclusion, just because a vintage mechanical watch has a high jewel count does not automatically make it more accurate, more functional or longer-lasting.

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Vintage Watch Parts, Watch Parts