57 stories
The Bench
How watches actually work, explained properly. One subject at a time, from the sources that set the rules.
Latest · N° 48 · 4 min
Ceramic trades scratches for chips
Watch ceramic is exceptionally hard and keeps its finish through abrasion that marks metal. Its low tolerance for deformation means a sharp impact can produce a chip or fracture instead.
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N° 47 · 4 minA faster beat spends power to make each disturbance matter lessA high-frequency balance receives more impulses and divides time more finely. It can recover from brief disturbances sooner, but friction, power reserve and regulation still decide whether the watch is accurate.
N° 46 · 4 minHeat-blued hands are wearing a film thinner than lightThe blue is not paint. Heating polished steel grows a transparent oxide layer, and interference within that extremely thin film selects the colour your eye receives.
N° 45 · 4 minA dry pressure test can find a leak without wetting the watchA modern tester changes the air pressure around a closed watch and measures minute case deformation. The watch can fail without a drop reaching the movement.
N° 44 · 5 minA tachymeter measures one of anything, not only one kilometreThe scale converts the time taken for one unit into a rate per hour. The unit can be a kilometre, a mile, a bottle or a component, provided the event is regular and quick enough.
N° 43 · 5 minGrade 2 and Grade 5 titanium solve different problemsGrade 2 is commercially pure, corrosion-resistant and comparatively formable. Grade 5 adds aluminium and vanadium for much greater strength, with a different price and manufacturing burden.
N° 42 · 5 minSpring Drive is mainspring-powered and quartz-governedA wound spring supplies every joule that moves the hands. A quartz oscillator and electromagnetic brake decide how quickly that energy is allowed to escape.
N° 41 · 5 minA screw-down crown locks a seal it did not createThreads keep the crown seated and protect it from accidental movement. The water barrier comes from compressed gaskets, which can age whether the crown is screwed down or not.
N° 40 · 5 minCharging your lume does not use it upModern photoluminescent paint stores light and releases it again without consuming a finite charge. It can age, but reading it at night is not what wears it out.
N° 39 · 5 minA split-seconds chronograph is two hands and a clamp pretending to be oneThe extra seconds hand hides beneath the first until a clamp arrests it. Press again and a heart-shaped cam brings the pair back together while the chronograph keeps running.
N° 38 · 4 minGuilloché names the cut, not the patternClous de Paris, barleycorn and waves describe what you see. Guilloché describes how a geometric pattern is generated and engraved into the surface.
N° 37 · 5 minShock resistant means a one-metre fall onto woodThe standard behind the words is more specific than the phrase sounds. It simulates an accidental fall onto a wooden floor, then checks whether the watch still keeps acceptable time.
N° 36 · 4 min904L survives corrosion better, not desk scratchesRolex chose a highly corrosion-resistant stainless steel and gave it a famous name. Its advantage is chemical resilience and polish, not immunity from the ordinary marks of wear.
N° 35 · 5 minThere is no universal danger zone for changing the dateThe familiar warning about changing a watch between nine and three is useful, but it is not a law of mechanics. The unsafe hours belong to the calibre, not the clock face.
N° 34 · 4 minHow a jumping-hour display spends its energyAn instantaneous hour change stores energy and releases it to move a display disc. The jump must be quick and reliable without taking too much torque from the movement.
N° 33 · 4 minWhy two meteorite dials never show the same patternThe visible lines in iron meteorite come from crystal structures that formed during extremely slow cooling. Cutting angle, etching and the parent material make each dial different.
N° 32 · 4 minWhat a timegrapher actually measuresRate and beat error come from the timing of the escapement sounds. Amplitude is calculated from that timing, so the lift-angle setting matters.
N° 31 · 4 minWhy an enamel dial is often enamelled on the backCounter-enamel on the rear of a metal dial helps balance the stresses created during firing. It is a structural part of traditional enamelling, even though the owner rarely sees it.
N° 30 · 4 minWhy watch oil moves, and what that means for servicingWatch lubricants work in quantities too small to see. Surface treatments, grease chemistry and careful application keep them near the contacts that need them, but ageing and migration still set limits.
N° 29 · 5 minWhat actually holds a watch strap to the caseMost removable straps and bracelets rely on small spring bars fitted between the lugs. Their diameter, end shape, length and condition matter more than their size suggests.
N° 28 · 4 minNickel in watches: what the release limit measuresSkin-contact rules focus on how much nickel a product releases over time, not simply whether an alloy contains nickel. Coatings must also remain effective through simulated wear.
N° 27 · 4 minHow the same ETA calibre becomes a different watchA shared base movement can be supplied in different grades and then adjusted, modified, finished and supported differently. The calibre name is the beginning of the comparison.
N° 26 · 4 minWhat ‘Swiss Made’ legally requires on a watchSwiss Made is an origin rule with requirements for the movement, assembly, inspection and Swiss share of manufacturing costs. It does not mean every component was made in Switzerland.
N° 25 · 5 minWhat military standards can teach us about dial legibilityNumeral size, contrast, stroke width and reflection can all be measured. Military guidance offers useful tests for watch dials, even though it was not written as a rulebook for consumer watches.
N° 24 · 4 minWhy a radio-controlled watch may not set itselfRadio-controlled watches receive low-frequency time signals; they do not transmit or know their location. Reception, home-city settings and transmitter coverage determine whether they update correctly.
N° 23 · 4 minHow a soft-iron cage protects a mechanical watchA soft-iron enclosure redirects magnetic flux around the movement. It is magnetic shielding, not the electric-field shielding usually meant by a Faraday cage.
N° 22 · 4 minAnnual and perpetual calendars: what happens on 1 MarchAn annual calendar distinguishes 30-day and 31-day months but needs help after February. A perpetual calendar also tracks the leap-year cycle, with one distant Gregorian exception.
N° 21 · 4 minForged carbon and carbon-fibre laminate are not the sameBoth use carbon fibres held in resin, but chopped-fibre moulding and layered woven composites create different structures, appearances and design possibilities.
N° 20 · 4 minWhy Rolex and Patek use free-sprung balancesA conventional regulator changes the hairspring's active length with curb pins. A free-sprung balance leaves the spring fixed and adjusts rate by moving mass on the balance wheel.
N° 19 · 5 minWhat a NATO strap actually isThe familiar one-piece nylon strap grew from a British military specification, but NATO is now a broad retail label. Construction matters more than the name.
N° 18 · 5 minWhy anti-reflective coatings can scratch before sapphire doesSapphire is extremely hard, but the optical films applied to it are much thinner and can mark under abrasion. Coating placement determines whether those marks are exposed to daily wear.
N° 17 · 4 minWhy temperature changes a quartz watch's rateA standard tuning-fork quartz crystal has a curved frequency response to temperature. Its circuit is adjusted around that behaviour, while thermocompensated movements actively correct for it.
N° 16 · 4 minWho actually needs a helium escape valveThe valve addresses pressure that can build inside a watch during prolonged saturation diving. It has little role in ordinary scuba diving, swimming or daily wear.
N° 15 · 4 minHow an equation-of-time watch follows the SunApparent solar time moves ahead of and behind ordinary clock time through the year. A shaped cam turns that annual variation into a mechanical display.
N° 14 · 4 minWhat 3N, 4N and 5N gold colours meanN colour numbers describe ranges used for coloured gold alloys and coatings. More copper generally shifts yellow gold towards pink and red, but the finished watch also depends on composition, process and surface.
N° 13 · 4 minWhat an overcoil does to a hairspringAn overcoil lifts and curves the hairspring's outer turn so the spring can breathe more concentrically. It can improve positional behaviour, but it is not the only route to a good oscillator.
N° 12 · 4 minWhy an independent watchmaker may not be able to get the partsSome manufacturers limit parts, tools and technical information to approved service networks. That can leave a capable independent repairer unable to complete an otherwise straightforward job.
N° 11 · 5 minHow a sunburst dial moves lightA sunburst finish uses fine radial texture to send reflected light in different directions. The bright band that appears to travel across the dial is produced by geometry, not moving colour.
N° 10 · 4 minWhat a dying battery does to a quartz watchA quartz oscillator usually keeps its rate as voltage falls, but the motor eventually lacks enough energy to move the hands reliably. Warning systems make that failure visible before the watch stops.
N° 09 · 4 minHow watch gaskets age and lose their sealElastomer gaskets can harden, flatten, swell or crack with time and exposure. Water resistance depends on their condition, lubrication, compression and the surfaces around them.
N° 08 · 4 minWhy a moonphase display does not copy the Moon's exact shapeMost moonphase watches use a rotating disc behind a shaped aperture. The familiar waxing and waning form comes from that display geometry, while the gearing controls the calendar error.
N° 07 · 4 minWhat DLC coating is, and how a black watch wearsDiamond-like carbon is a family of hard, thin carbon-based coatings applied over a prepared case. It resists wear well, but the substrate, layer system and impact still determine visible damage.
N° 06 · 4 minColumn wheel or cam: what the switch actually changesBoth systems control a mechanical chronograph. The practical differences are pusher feel, construction and service, while the clutch determines how cleanly the chronograph engages.
N° 05 · 4 minHow a brand-new watch reaches the grey marketGrey-market watches are genuine goods sold outside a brand's authorised retail channel. The lower price often reflects distribution pressure, exchanged warranty support and a different service relationship.
N° 04 · 4 minWhy watchmakers decorate parts you may never seeHidden finishing can remove manufacturing traces, preserve a workshop standard and show care across the complete movement. It should still be judged separately from mechanical performance.
N° 03 · 4 minSteel, silicon and Nivachron hairsprings comparedHairspring materials affect magnetism, temperature behaviour, manufacture and repair. Their geometry and adjustment still matter as much as the material name.
N° 02 · 4 minCOSC, METAS and the Geneva Seal measure different thingsCOSC tests uncased movements for rate. METAS tests complete watches across a broader performance programme. The Geneva Seal combines origin, construction and finishing requirements with completed-watch checks.
N° 01 · 4 minWhy every bronze watch develops a different patinaBronze changes as copper in the alloy reacts with air, moisture, salts and skin chemistry. Alloy composition, surface finish and wear make each case age differently.