Why Do Mechanical Watch Movements Have Jewel Bearings?
Let’s admit it.
We have all been caught at least once, staring blankly at the mechanical movements of our watches.
Who won’t? Watch movements are beautiful complicated machines especially in manual winding watches. Every cog and gear work flawlessly together to produce its ‘ticking’ heart beat and your watch practically comes to life. But while at it, I’m sure you must have noticed the beautiful jewel bearings sitting in your movements. Have you ever wonder what are they used for? Are they really there for aesthetic purposes?
WHAT ARE JEWELS USED FOR?
As mentioned earlier, watch movements are complicated machines and comprise of many tiny components working together. Since most of these parts are made of metal, it is inevitable that they will cause friction, leading to wear and tear. Irreversible damage will eventually occur when the vital areas such as axles or escapements grind into smaller parts, destroying its near-perfect system.
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Since many jewels and gemstones such as rubies and sapphire are much harder than metals, jewel bearings are placed at vital pivots to reduce wear and tear. This encourages a more efficient transfer of power from the mainspring to the escapement. Aside from their hardness, jewels also have good temperature stability, low kinetic friction and highly consistent static friction. Moreover, the smooth polished finishing of the jewel bearings also helps a lot in creating a less disturbed environment.
ARE THEY REAL JEWELS? ARE THEY VALUABLE?
Unless you have a watch dated from the early 20th century, most of the watches for men you see today are using synthetic jewels.
Aside from cost factors, synthetic jewels are easier to work with. They have the exact same chemical compositions as their natural counterparts except for their impurities and trace elements that give natural gems its unique color. Due to this reason, almost all of the synthetic jewel bearings you see in your watch movements are clear with a slight tinge of pink.
MORE JEWEL BEARINGS MEANS MORE VALUABLE?
Contrary to popular belief, the jewel bearings have almost zero monetary value. What determines the value of a natural jewel is its color hue, tone and saturation and other factors. Synthetic jewel bearings merely have the same chemical composition.
While it is true that more jewel bearings are required for complicated chronograph movements such as the Valjoux 7750 movement, it doesn’t mean more jewel bearings you have, the more valuable is your watch.
A well-designed movement only includes jewels only where it is needed. Depending on the design of the movement, more jewel bearings will be required if there are more pivot points. A simple manual winding watch movement such as the Unitas ETA 6497 has 17 jewels and is an amazing, robust workhorse movement.
Depending on the types of watch movement used, most of the best dress watches today use between 17 jewels to 23 jewels in their movements. Unfortunately, there are some unethical watch brands who began to insert unnecessary jewel bearings as in parts of the movements where they weren’t needed at all in order to increase the overall perceived value of the watch.
Jewels or not
Rather than depending on the numbers of jewels in a movement, it is far more important to understand the movement itself before you buy a mechanical watch.
We hope you have a better understanding of watch movements after reading this article. Is there anything interesting facts on jewel bearings we have missed out? Let us know in the comment section below!