Case. Crystal. Lume. Bezel. When it comes to watchmaking, there seems to be a whole host of jargon referring to the various different parts of a wristwatch. Some are probably familiar, or at least easy enough to work out, but others might need a little explanation, particularly if you’re new to the world of watches. Which is why we decided to approach Ian Elliot and Alex Brown, the two co-founders of our favourite British watch brand, Elliot Brown, to break it all down for us. They were more than happy to help, and obligingly even worked up a handy illustration, based on their hard-as-nails Holton Professional model. So, if you’re interested in the (dangerously addictive) world of watches, take a look at our concise glossary of common watch terms. You’ll be more than familiar with elementary horology in no time at all.
Glossary of Common Watch Terms
Bezel
The bezel is a metal ring surrounding the watch face, which helps to hold the crystal in place. On sports or tool watches, it also has additional timekeeping functionality and may rotate accordingly. There are numerous different types of bezel scales, including tachymeters, pulsometers, telemeters, decimeters, GMT bezels, compasses, count-up and countdown timers, yacht-timers and slide rules.
The most common type is a count-up bezel, used on divers’ watches for calculating elapsed time. It features a scale from 0 to 60 around the bezel, aligning with the minutes in the hour. The first 15 or 20 minutes are typically marked in one-minute increments. This is designed to ensure the diver does not run out of air during a dive. ISO 6425 is the international standard for dive watches, which dictates that a dive watch should be fitted with a unidirectional bezel that only rotates counter-clockwise. This is a safety feature, as it means that if you accidentally bump the bezel while diving, you can only have less time and more oxygen mix in your SCUBA tank. For similar reasons, the bezel on a divers’ watch is often ratcheted to help prevent it from being knocked out of its set position.
Elliot Brown: “The bezels of our Holton and Tyneham watches are individually case-hardened. They end up six times harder than standard marine-grade stainless steel, which means they are incredibly hard to scratch or mark even under severe impacts. Unlike most dive watches, the bezel of the Holton also has a hash mark every minute and instead of being printed on, every hash mark is debossed then filled with SuperLuminova C3.”
Case
The case forms the main body of the watch, and houses the dial, movement and other working parts, as well as the battery in a quartz watch. More than any other aspect of a watch, it dictates a timepiece’s overall look and feel, as well as how it ‘wears’ on the wrist.
Cases come in several different shapes and styles: round, square, rectangular (often called a ‘tank’ watch), cushion, tonneau (or ‘barrel’ case), asymmetric and so on. They can also be made from different materials, most commonly steel but also titanium. Similarly, they can be finished in a host of different ways: polished, brushed or bead- and sand-blasted steel, gold or rose gold, bronze, gunmetal or black, attained via the use of a Physical Vapour Deposition (PVD) treatment.
EB: “Our watch cases are machined from solid 316L marine-grade stainless steel. This grade of steel has improved corrosion resistance and a low carbon content, which makes it well-suited to outdoor and marine environments.”
Caseback
A caseback is screwed or bolted to the rear of the watch case and gives access to the inner workings of the watch. It is usually a steel disc, frequently engraved or inscribed with decorative elements as well as details like the model of the watch, its serial number, place of manufacture and internal movement. Some watches feature transparent ‘display’ or ‘exhibition’ casebacks made of glass or sapphire crystal. These allow the wearer to inspect the workings of the watch movement.
EB: “Compressor casebacks increase their sealing capability as pressure increases by being bolted down rather than screwed. When pressure increases, the caseback is able to slide up the bolts by a fraction of a mm to compress the seals that little bit more. During construction, bolting the caseback down compresses the seal perfectly, without the risk of the seal tearing or folding due to over-torsional stresses associated with tightening. It has the added benefit that the caseback itself is always 100% aligned. For us, there’s nothing more frustrating than seeing beautiful caseback detailing at a jaunty angle, so we did away with it and added functionality at the same time”.
Complications
This is the term given to the additional functions of a watch: basically, anything it does beyond telling the time. There are innumerable complications, from watches that depict the phases of the moon to perpetual calendars, often shown via the use of sub-dials on the face of the watch itself.
EB: “The Tyneham has a couple of understated and elegant automatic complications; namely a subtle date window at 5H and a 40-hour power reserve at 1H, which instantly shows the wearer the state of the mainspring winding”.
Crown
The crown is placed at the edge of the case and consists of a winder and stem. It is usually found at the 3 o’clock position, though it is sometimes placed at 4 o’clock to be less obtrusive, and occasionally at 9 o’clock on watches with a left-hand crown. It is used to set the time, and often the day/date too, by pulling it out to two or three positions and then turning it either clockwise or counter-clockwise, depending on the type of movement. On manual mechanical watches and automatic watches that can be hand-wound, it is also used to wind the mainspring of the watch.
EB: “The crowns of sports watches typically have a screw-down mechanism where, after adjusting the time or date, the crown needs to be screwed back into the watch case for the crown seal to become operative. That’s all well and good if you remember to screw it down, but many people forget, which means that if the watch sees any water, it’s often game over. This problem has been completely overcome by a simple yet elegant engineering solution. We use triple seals that work whether the crown is pulled out or seated back against the watch case. We do use screw down crowns, but two seals remain operative even when the crown is unscrewed, so you can never get it wrong”.
Crystal
The transparent ‘glass’ of a watch is technically known as the watch crystal. They can be domed, flush, recessed or sometimes even protrude from the surface of the bezel. They are also sometimes bevelled at the edge, which helps to prevent them from chipping. Many have anti-reflective coatings to improve watch readability.
Crystals are either made from plastic/acrylic, mineral glass or sapphire. Synthetic sapphire is made by crystallizing pure aluminium oxide at very high temperatures. It forms one of the hardest substances on earth, so is highly scratch resistant.
EB: “Crystals are the primary weak point of many watches, so we go to great lengths to test them to make sure they’re fit for purpose. We use either hardened and tempered mineral crystal or sapphire that’s incredibly thick – 3.2mm on the Bloxworth. We treat every crystal with an anti-reflective coating, but we only apply it to the underside to give perfect vision in all lighting conditions, without the annoying fingerprinting associated with anti-reflective outer coatings. Then every crystal is pressed into the watch case inside an I-ring seal. We’re quite unusual in that we colour match the I-ring to the dial colour. It’s a tiny detail you’d probably never notice until we told you, but if you look at other watches that don't match the I-ring, you'll see the difference”.
Date window
Sometimes called a date aperture, this is a small window in the dial of the watch that shows the numeric date. Some watches have no date window at all, some have only a date aperture, others have a day-date aperture that also indicates what day of the week it is. Date windows are usually – but not always – placed between 3 and 6 o’clock on the dial for the sake of legibility and design harmony.
EB: “Where space permits inside the watch, we print our date indices radially on the internal ring rather than vertically, ensuring better and crisper alignment within the date aperture of the dial”.
Dial
Also known as the face, the dial is the part of the watch that displays the time, via printed numbers (indices) and/or hour and minute markers. It sits beneath the hands and may incorporate raised hour batons and sub-dials. The dial usually also features the brand name and logo, as well as other details like the movement type (automatic or quartz), place of manufacture – particularly if Swiss or Japanese – and degree of water-resistance (in metres or bars). The dial is surrounded by a chapter ring and protected by the crystal and bezel.
EB: “Our watch dials are designed like a story that sits perfectly with the hands, hour batons, micro markers, sub-dials and inner bezels. When we created the Kimmeridge, our women’s model, we set a course on a smaller, more elegant version of the Canford. The two look remarkably similar. It would appear a simple task to minimise the Canford design by a few mm, but in reality it took 50 design versions until we knew we had ‘the one’. If you compare the Kimmeridge with the Canford, you’ll spot that there’s no shield under the words Elliot Brown on the dial, because it lacked sophistication in this execution. Instead, the balancing arm on the end of the seconds hand is the home of the shield. It’s a perfect example of how we obsess over the smallest detail, so you can simply enjoy the watches we’ve created for what they are”.
Hands
Most watches have a shorter hour hand, a longer minute hand and a thinner seconds hand, which work together with the dial to display the time. GMT watches also have a fourth hand, which indicates the time in an additional time zone.
Indices
The indices are the numbers of a watch as printed on the dial. Classic indices use Arabic numerals from 1-12, or roman numerals from I-XII. Some watches show a mix of Arabic and roman numerals, which is known as a ‘California’ or ‘Cali’ dial. In addition, many specialist watches display 24-hr markings, while some – particularly pilot or aviator watches – tend to show the minutes more prominently than hours. Other watches omit indices altogether, instead displaying the hours via markers or batons.
Lugs
These are the metal nubs or arms protruding from the top and bottom of the case, which enable the watch to be attached to a strap, band or bracelet via strap bars.
Lume
Short for luminescence, ‘lume’ is the term that refers to any part of the watch that glows in the dark, enabling the time to be read at night or in low-light conditions.
EB: “Luminosity is something we take very seriously and use wisely. When we design a watch, its night-time appearance has to be as on-point as its daytime persona, with simple, easy-to-read markings that will glow all night – up to 8 hours in fact, provided the watch has had a good ‘charge’ for a few hours in daylight. A common misconception about luminosity of watch markings is that they should just glow no matter what, but if you treat them like a solar panel that needs to take in energy before it can give it out, you’ll be on the right path. We only use a material called SuperLuminova – it’s the best we know of. Whilst some watches feature gas discharge tubes and electroluminescence, these are too bright for the military applications that some of our watches are put through. So, SuperLuminova strikes the right balance for us”.
Movement
A movement or calibre is the internal mechanism that operates the watch. Movements can be either quartz or mechanical. Quartz movements are very accurate and powered by a cell, button or coin battery, with few moving parts. The battery sends an electrical current through a small quartz crystal, electrifying the crystal to create vibrations. These vibrations keep the movement oscillating and drive the motor to move the watch hands.
A mechanical movement uses energy from a mainspring to power the watch. This spring stores energy and transfers it through a series of gears and smaller springs. Mechanical movements can be manual (hand-wound) or automatic (self-winding). The former require regular winding via the crown, while the latter harness energy through a rotor, which is activated via the natural motion of the wearer’s wrist. As long as the watch is worn regularly, it will maintain power without requiring winding, though many modern automatic watches can also be wound by hand. In addition, many have a ‘hacking’ function, which is the ability to stop the movement at will by pulling out the crown. It is useful for synchronizing a watch with another, or with a highly accurate clock.
An easy way to tell a quartz from a mechanical movement is by looking at the second hand. Quartz watches have a regular ‘ticking’ second hand, while mechanical watches have a smooth, sweeping second hand.
EB: “We house the movement within a shock protection system, comprised of a stainless housing (rather than a plastic clip mount as used by the rest of the industry) that floats inside the outer watch case, held by a series of silicone elastomer dampers. The dampers sit within precisely machined recesses on the inner faces of the watch case. Machining tolerances are extremely fine as the movement has to be a push (interference) fit into the housing, as are the dampers into the watch case. The effect is that the outer casing can take incredibly hard hits whilst the relatively fragile movement remains unscathed”.
Pusher
This is the secondary button on the side of a watch, in addition to the crown, that operates other functions such as the chronograph.
Strap Bars
These metal bars are usually hidden from view. They are usually sprung, and sit between the lugs of the watch. To attach a watch to a strap, the bars are threaded through holes in the ends of the watch strap (or the end links of a metal watch bracelet). With a NATO strap, the strap is threaded over the bars and underneath the caseback of the watch itself.
EB: “Spring bars are the industry norm but they’re weak. Why would you risk a loved, valuable timepiece on such flimsy retaining devices? So, we set about creating a more elegant solution, and have developed a single solid steel bar, threaded and recessed, with a matching torx-style driver that locks into the end of the bar. A strap change using this system is the work of a few seconds, yet it’s totally indestructible – reliant only on the strength of the material the strap is made from, rather than acting as the primary weakness”.
Strap
Usually referred to as a ‘watch band’ in the US, this is how a watch is attached to your wrist. It usually incorporates a buckle and at least one keeper or loop. Straps are traditionally made of leather or metal (in which case it is usually referred to as a bracelet), but can also be made of canvas, rubber or synthetic fabrics such as nylon webbing.
EB: “Our watch strap webbing is woven specifically for Elliot Brown by a traditional family-run business, Bowmer Bond in Ashbourne, Derbyshire. They recommissioned a Victorian shuttle loom called Dolly, fed her with small-batch dyed, textured yarn and set about creating a beautifully technical slice of fabric. The patented buckle is designed to hold the webbing securely in a hinged clamp and ladder lock, eliminating excess fabric and flapping”.
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