Jewels in watches are much more prosaic than their name suggests.

When we read about terms used in mechanical watchmaking, we often hear terms like “jewels” or “rubies,” and we often fantasize about the hidden riches inside our watches. There are some fiction stories where thieves steal the jewels of a watch!

Well, the term “ruby” or “jewel” is used to refer to tiny artificial stones (jewel bearings) that are set inside the watch. They are shaped like a torus, are man-made, and I must add, practically worthless – sorry for shattering your dreams of becoming rich in this way.

If you examine a watch movement, you can notice that these rubies are set in particular places (so, they are not ornamental, even if they do have a definite decor effect).

They are usually set in pairs (one above and one below) in correspondence of the pivots of the gears, and they are generally drilled through with a tiny hole.

Cross section of jewel bearings

You can see it here (it’s a cross-section) what it happens. The pivots of the gears are set precisely through these stones, one up, one down, so they can rotate freely.

And why using jewels instead of plain metal bearings? (mind you, lots of watches use bearings too – especially lower-cost mechanical watches and quartz mechanisms).

The answer is, because of attrition.

Attrition and jewels

First of all, a small note. Everybody knows that the hardest substance on Earth is the diamond. The hardness of materials has been measured by a scale, known as Mohs Scale. The diamond has a value of 10 on this hardness scale. On the other hand, the talc, with just a value of 1. Most of other materials stay between these two extremes. Well, corundum has a value of 9 on the Mohs scale – and rubies and sapphires are two forms of corundum. Metals have a lesser value by much: gold has 2.5, brass and nickel have 3, platinum has 4, iron and steel 4.5, titanium has 6, and tungsten carbide has 9.

You can see that a jewel is harder, even if more brittle than its metal counterpart, the bushing, so a steel pivot rotates inside it more effortlessly and with less grinding on it than it would in a bearing made of metal (usually, brass). The static coefficient of friction of brass-on-steel is 0.35, while the one of sapphire-on-steel is 0.10–0.15, so three times less.

It means a smoother and better transmission of movement, less attrition, and extended durability of the watch without constant maintenance.

As you can easily imagine, setting a jewel inside a micro-mechanics element like a bridge of a watch is a complicated issue. This means that jewel setting used to be reserved for higher-quality (and higher cost) watches.

Nicolas Fatio de Duillers

Use of jewels in watchmaking

Jewel bearings were introduced in watches by Nicolas Fatio (or Facio) de Duillier and Pierre and Jacob Debaufre around 1702. Still, they did not become widely used as they were very costly. The first jewels were, indeed, shards of real gemstones. Watches often mounted garnet, quartz, or even glass; only the top quality ones mounted sapphire, ruby, and even diamond jewels.

In 1902, everything changed, because Auguste Verneuil developed a chemical process to create synthetic jewels. Hence, they became quite cheaper and gained widespread use in watchmaking. Jewels in modern watches are generally rubies or corundum, one of the hardest substances known (apart from diamond).

So, modern watches tend to use jewels on every part that is subject to constant grinding of metal against metal. This includes the pivots of the wheels of a typical wind-up watch (wheel train, escapement wheel, balance wheel), as well as two other critical elements: the pallet fork endings and the single impulse jewel in the center of the balance wheel.

Along the more ordinary torus-shaped jewels housing the pinions of the wheel train wheels, we also have some unique jewels called capstones. These jewels are used in wheels where friction is critical, as the balance wheel pinions. They are set so to prevent the shaft of the wheel from touching the surface of the jewel, and also, to create a space called “oil cup” which helps to lubricate the mechanism better.

More often than not, these capstones are held in place with shock-resisting mechanisms, such as the Incabloc.

Jewel-count. Beware of exaggerations!

Before the introduction of shock-resisting systems (around 1932), the best wind-up mechanical movements without complications mounted 15 jewels. After that, the jewels rose to 17. Automatic and complicated movements usually mount more jewels, as they have more wheels requiring them.

Waltham Autochron, mounting 100 (useless) jewels

From their introduction, watch manufacturers defined the quality of the movements using terms such as “XX Jewels,” where XX was the number of jewels mounted into the watch.

This term diffused itself in product descriptions, becoming a natural equivalence to the public of “more jewels, more quality.”

So much that some companies, between which Waltham and Orient, launched on the market watches featuring 100-jewel movements. These movements used aesthetically-placed jewels, which had no function whatsoever, except to let the manufacturer say that there were 100 jewels inside the watch.

This example is a practical effect of the fascination that a name like “jewel” can have on someone who does not know the functional aspects of jewels inside a watch.

We should note that this practice, which was deceiving for the customers, was first condemned, and then prohibited by law.

Today, a manufacturer cannot place jewels inside a movement that have no practical purpose. If it does, he cannot refer to them in its communication.

You can find much more about horology and its fascinating history in The Watch Manual, a thorough e-book that explains all the basics about watchmaking and its protagonists.

To download a FREE 8-chapter extract from The Watch Manual

What to do if water has gotten into an old Rolex and is fogging the glass?

As time goes by, watches lose their water resistance. It happens. And if you are experiencing this issue, well, you have a couple solutions.

The easy solution is as follows.

Get it to your watchmaker for a service, quick.

Rolex uses a unique kind of closure for its watches (the famous – and patented – Oyster case) which requires a special tool for opening. This tool follows the small indents at the base of the backcase, so rotating it you can unscrew it. It is not available to everybody, and only watchmakers normally have it. Of course you could buy it, but it is both costly and not really suited to DIY. Remember that a false move might make you scratch deeply your watch. Not really an issue on a Seiko 5, but on a Rolex, it hurts.

If you leave the moisture inside the watch, some parts of it would start to rust, and this is something that you do not want at all.

Do not try to do anything by yourself. If you do not know what to do, you could eventually make something wrong, and to remedy it it would be costly or downright impossible.

You might manage to remove some fogginess through the use of different methods, like rice, silica gel, cat litter and such, but it would require you to remove the back of the watch to be effective. Are you really ready for that?

The hard solution requires instead some manual dexterity, and involves significant risk to the watch itself. Plus it will void your warranty, if the watch had one.

Please note: what follows is a somewhat detailed description of the procedure needed to open up a Rolex.

I have been asked in other platforms why should I give this detailed how-to guide to anyone, as the good and right answer is obviously the first. I did not want to boast my operational knowledge of habillage: I just wanted to explain the reasons why lifting the back of a watch to let go the vapor formed inside – as it would be logical to do – is easier said than done. If I did not, anyone reading could assume it was an easy task – something that everyone could safely achieve, and save a few bucks. Well, as you can see, there’s much more into it – and this is what your watchmaker does when servicing a watch (any watch) that has this kind of issue, not just a Rolex.

So, caveat lector – proceed at your own risk.

Here’s the Rolex opener tool I was talking about before. This one is a Chinese-made compatible one. It is made of soft, low-quality steel, so it is good for few uses – but it is relatively affordable (around 30 USD bought online). Good quality ones featuring professional components and materials – that is, watchmaker’s quality – are made by companies like Horotec and Bergeon, but they cost significantly more (like 5 times more).

As you can see, you have to place the die over the watch when it is properly held in a vice with its back upwards.

The four teflon/hard plastic holders ensure the watch does not get scratched if something slips out of control.
What follows is a typical Oyster case back. As you can readily understand, you need several dies to find the one which fits your watch size, as we have many diameters, from the Ladies tiniest to the Gentleman’s biggest. When you have secured the watch case into the vice, and the vice has been placed in a bench vise, you are now ready to put the wrench into the die, press hard against the back of the watch and turn so to unscrew it.

If you do not place everything perfectly aligned, and something slips, well…

You could end up with something like this. That is, a severely scratched back which would require an intensive work to return to a good state (not pristine anymore – if you scratch something, you remove material from it). Even if a professional polishes this watch, the deep scratches on its base will continue to be noticeable.

Let’s pretend you have done everything right, and managed to remove the back safely and securely. You end up with this situation.

Congrats. You’ve made it!

Now, place your watch like this under a closed container so to protect the watch movement from dust. You could place a couple packets of silica gel next to it, but not really necessary. Leave it like this for a couple days. Then proceed to screw the back again into the watch, with all that this action entails.

Remember: if water got into the watch the first time, it is because it found a way to get into it first!

This means that either you had not screwed the crown in fully, or the o-rings protecting the watch have to be changed or serviced, because they are not water resistant anymore. So now you have a new problem to solve: to ensure that your watch is water resistant again.

Watches have different kind of gaskets, often made in silicone, which have an operative life of around five to ten years, and they must be periodically greased and changed to ensure they stay water-resistant. You can see it in the Rolex back, housed in a recess around the back opening.

They are applied to the backs, as well as to the crowns. Yes, these tiny gaskets on the winding stem have to be periodically lubed and changed as well to ensure that the watch stays water resistant.

When you have done all of this, now you can check if the watch is water resistant again. You’d need someone who has a kind of tool for that, though, since doing it traditionally – that is, in water – would be dangerous, especially if you have made a mistake and the water resistance is impaired somewhere…

You can get a hobbyist-level one for around 300 USD, but the good ones can cost you five times more.

Well, now you have finished, and your watch has no moisture into it anymore, nor will get any later!

If you have gone this far, you could start thinking about selling watchmaking services to your friends, family, and acquantainces.

As you are now thinking, this service is something that professionals usually do – for a few bucks. This knowledge, and tools assortment, are better used by a professional. And the answer is yes: unless you are a serious hobbyist, or a professional, do not even think about doing all of this by yourself. It would possibly make the problem bigger and more costly to solve.

You can find much more about horology and its fascinating history in The Watch Manual, a thorough e-book that explains all the basics about watchmaking and its protagonists.

To download a FREE 8-chapter extract from The Watch Manual

Has anyone ever bought a watch and found it was going backwards?

While the possibility seems intriguing, this would happen only if the watch was designed to do so, like in the original watch issued by Apple, and in some contemporary watches made for specific purposes. It is impossible that it happens by mishap.

A couple of unusual Franck Muller timepieces

There are watches built to run like that, and some come from famous brands as well, as these two Franck Muller demonstrate. However, if you mean that it could happen because of a technical fault, the answer is negative. Except by a demonical possession, that is.

It is technically impossible. And I will walk you by it and explain why.

There are several reasons why an ordinary watch – that is, one running clockwise – cannot run backwards.This would mean that I will be explaining a bit how a typical mechanical watch works.

1 – the shape of the arbor

three different arbors

First of all, to make hands turn backwards its wheels should rotate on the other direction – counterclockwise. This means that in a regular watch, in order for this to happen, the watch mainspring should be mounted on the opposite way. While this would be ideally possible, it could not happen, because if you do so the mainspring would not hold onto its central axis (called arbor).

The mainspring has a hole on one end (as you can see in the photo), and is coiled around the arbor when you wind it.

As you can see, however, the arbor has a sort of nail where this hole gets into – but you can also notice that its shape is eccentric: it has a sort of inner recess where the end of the mainspring goes.

If you try to mount it on the other direction, it will not stick in the nail, because the shape of the arbor would make it slide away. This is a sort of safety measure as well, so you have to mount the mainspring in the right direction.

Mainspring and bridle

2 – the direction of the click

The click is a small rotating element fitted on the ratchet wheel. When you wind up a watch and hear that click click click sound, well – this is the click in action. It is very visible in this photo at eight o’clock – the small rotating element on the left, which is a sort of safety mechanism equipped with a three teeth and a small spring holding it in place.

The function of the click is to let the ratchet wheel rotate in one direction only, thus storing energy in the mainspring. When the wheel tries to recoil, the small spring in the click makes the click rotate, so its big tooth engages the teeth of the ratchet wheel, effectively impeding it from rotating back.

The only way to do so is to manually rotate the click out of the way and hold it in place as the mainspring discharges itself. Incidentally, you can control its discharge by holding the crown, so it does it slowly. This means that the stored energy of the mainspring cannot release its energy by simply turning back, and can only be released from the other end of the energy distribution chain – that is, setting the movement in motion.

So, even if you somehow manage to assemble the mainspring backwards, it could not rotate on the other direction, because the click would intervene and stop its rotation.

A typical manual winding movement

3 – the shape of the escapement wheel and pallet fork

The escapement wheel is at the end of the wheel train, and is the one propelling the pallet – which most normally is in the shape of an anchor. You can see them below, the escapement on the right and the pallet on the left. The escapement is called a wheel, but its teeth are quite different from the ones used in normal gears.

Escapement wheel and pallet fork

As you can see, they are not symmetrical. This means that the escapement is made to turn in one direction only. If you try to make it turn in the other direction, it would not, because its teeth could not effectively engage the two ends of the pallet fork, and get stuck.

You can readily see that the pallet fork itself is not symmetrical, either. One arm is longer than the other, and the two rubies are set at different angles. This means that to make it run in reverse, you’d have to mount both escapement wheel and pallet fork upside-down, which is obviously impossible as they would not fit with the other elements of the watch.

So, to end…

As you can see, making a mechanical watch work in reverse is impossible, since its construction is made to let the mechanism rotate in one direction only. To rotate backwards, a watch should be designed to do that: it cannot just happen by mishap.

You can find much more about horology and its fascinating history in The Watch Manual, a thorough e-book that explains all the basics about watchmaking and its protagonists.

To download a FREE 8-chapter extract from The Watch Manual


We are always slave to the trends of the fashion, and fashion comes and goes, even in watches.

What is the current trend for men’s watch sizes? Is the large watch fad finally fading?

I can tell you that yes, it is luckily over.

Watch fashion is like regular fashion: it comes and goes, and you cannot do anything about that. What is cool today won’t be cool tomorrow – with the added issue that watches have an average timespan that is far longer than the typical garment.

This means that when the fad is over, the watch is going to stay with you for a long time, if you are not prepared to reduce its price considerably for selling as a second-wrist.

Audemars Piguet Code 11.59, at 41 mm size

The latest launches of the major Maisons have standardized on one specific size, and it is 41 mm.

It seems that this has become the golden ratio of all things horology. The first company using this size has been Audemars Piguet, when it launched in 2019 its tepid Code 11.59 as a “unisex watch”. Its brand ambassadors – female and male as well – all wore the watch in different references, but the same size.

In 2020, Rolex has updated its lineup and launched the Submariner 124060 in this same size – 41 mm.

The modern 41mm Rolex Submariner No Date

So, the other companies are following suit.

Why are companies standardizing?

Well, the number one answer is because companies need to sell new watches, and the best way to do that is to induce people into buying them somehow. Social pressure is a powerful weapon, so if the crowd retains that your watch is too big (aka, outdated) you might cave in and buy a smaller watch because you want to belong to the crowd.

But there is another powerful reason which might not be that apparent.

Smaller watches look better on smaller and thinner persons.

Is the world average person becoming thinner? Not if you check the average American or European. But the average middle class of today lives in Asia. And Asians have smaller frames than Westerners.

The most recent stats of Swiss watch exports – which are public – indicate quite clearly that the majority of watches take the Asian route towards China and Hong Kong, where they are distributed in the region.

This means that the companies marketing departments do their best to accommodate their products to the desires and needs of the Eastern-based people, who happen to have smaller wrists on the average.

And this means women as well.

While once women had to wear “ladies watches”, which were tailored to fit a certain social stereotype, modern women are way different from before. And many of them wear men’s watches as a result, as they have more utilitarian needs than the ones fulfilled by cocktail watches.

Lindsey Vonn looking good with a Submariner

So, I expect that watches will continue to become smaller and more wearable for these reasons. While companies will continue to make oversize watches, the trend will eventually fade back into what it was: and exception and not the rule anymore.

This also means that the older vintage watches, which had smaller frames (as nuch as 30 mm for man’s watches) will become again stylish, and there is already a distinct trend towards that.

I also expect that Art Deco watches will become very hip again, as the square and rectangular shapes look gorgeous on smaller wrists.

Yours. truly, wearing an ATA (another brand by Doxa)

Of course, always remember that “size” has really little significance, as what is really important are the dimension and shape of the lugs, which can render a watch much bigger or smaller at the wrist. But this is another story altogether.

You can find much more about horology and its fascinating history in The Watch Manual, a thorough e-book that explains all the basics about watchmaking and its protagonists.

To download a FREE 8-chapter extract from The Watch Manual

How the mesmerizing tourbillon and carrousel work

A tourbillon movement works exactly like a traditional mechanical movement would.

The only difference from a traditional movement is that the assembly of the regulatory organ of the watch, that is, the balance wheel, rotates around itself, eccentrically on its cage in a proper tourbillon, or axially in a carrousel system (both work following the same principle, though – that is, making the balance wheel and its assembly rotate on their axis).

The traditional movement of a mechanical watch has a point-to-point distribution system. That is, the mainspring imparts energy to the watch movements, which is used to make the balance wheel oscillate back and forth. You can check it in this old Rolex movement: the balance wheel, on the bottom of the image, is held in its place by a bridge. Its 270° of oscillation happen always on the same axis.

A Rolex-made mechanical movement of a vintage Panerai.

his oscillation – which has a median amplitude of 270° – happens only in one axis, or as horologists say, “position”. This means that it could be subject to recurring errors depending on the position that the watch assumes.

The inventor of the tourbillon: Breguet

The inventor of tourbillons, Mr. Breguet, knew that this was the case.

Pocket watches (as in the beginning of the 1800s there were pocket watches only) had only two main positions in which they were used: a vertical carrying position, when they were worn and put in pockets, especially a waistcoat’s; and a horizontal position, when they were put on a table, face up, to let people work (write letters, have meetings and such).

This meant that the mechanisms could have been subject to tiny errors which would stack up in time. And one of the best solutions was to “average” this errors so to neutralize them. If the balance wheel rotates around itself every minute, the errors that it would get when it is at a 0° angle would be averaged by the error it gets at a 180° angle.

This was right, especially if we consider pocket watches, which was the case in the beginning of the 1800s.

So, Mr. Breguet developed and patented a system to let the balance wheels rotate around its axis to reduce this error in timekeeping as possible.

He achieved that by mounting the balance wheel, pallet and escapement, in a rotating cage. The rotation (which generally takes one minute to happen) was enough to ensure that the oscillations happened in different positions.

A tourbillon watch made by Guinand for Girard Perregaux

The assembly above, even if it isn’t so evident, groups together the last three elements of the watch works: the escapement wheel, the pallet, and the balance wheel.

Imagine them as if they were contained inside a cage that rotates on itself.

The system mounted inside the cage of a tourbillon: balance, pallet and escapement

As you might argue, this was perfectly logical in a pocket watch, but has much less sense in a wristwatch. Today, we wear watches on our wrist. This means that the position where a balance wheel operates constantly shifts, depending on the position of our arm, so the effect of a tourbillon would be lessened.

This is to say that our modern wristwatches are more precise vs. old pocket watches because we wear them on our wrist. The continual change of position makes them operate as they were using a tourbillon-based system.

However, there is one more thing to notice. Tourbillon systems are extremely appealing to watch.

The constant movement of the balance wheel in the tourbillon cage has a mesmerizing effect. This explains the increasing success of tourbillon watches from the Eighties onwards, when they have been re-discovered and relaunched.

Flatly said, currently a tourbillon is not really that effective. There are much better ways used to achieve good timekeeping performances than through a tourbillon.

A tourbillon watch by Hermès

However, tourbillons look extremely good, and any watch lover – or almost – would love to get one around his/her wrist. Even if it’s nowadays almost useless.

You can find much more about horology and its fascinating history in The Watch Manual, a thorough e-book that explains all the basics about watchmaking and its protagonists.

To download a FREE 8-chapter extract from The Watch Manual