Interactive study tools
Tools
A hub of interactive tools for narrowing an unknown movement, and for building intuition about how mechanisms behave. None of these tools issues a single certain verdict: horological identification is a process of narrowing candidates and confirming with physical evidence, not a lookup.
Identification
Movement Identifier
Narrow candidate calibres from the Movement Encyclopedia by plate architecture, escapement, winding system, jewel count, country and size. Results are always framed as possible candidates to confirm against markings, never as a single certain identification.
36 recorded calibres are consistent with these criteria. Narrow further using visible markings (grade name, jewel count, adjustment statements) to reduce the field, since this tool can only narrow candidates, not assert a single answer.
United States · 1940 – 1969Hamilton 992BThree-quarter plate nickel movement with damascened finish, motor barrel and micrometric regulator; designed specifically to satisfy railway time-service requirements.21 jewels · Swiss lever, exposed pallets · 16 size (approx. 43.1 mm)United States · 1883 – c. 1920sWaltham Model 1883Full-plate 18 size model produced in enormous quantity across many grades, from low-jewel utility movements to adjusted railroad grades.7 to 21 depending on grade jewels · Lever · 18 sizeFrance / Switzerland · c. 1770 onwardLépine Calibre (bar movement)Jean-Antoine Lépine's abandonment of the full top plate in favour of separate bars and bridges mounted on a single plate, removing the fusee and allowing a dramatically thinner watch.Variable; often jewelled to the escapement only jewels · Cylinder or lever depending on period · VariesSwitzerland · Mid-twentieth century to presentETA/Unitas 6497A large, simple bridge-type hand-wound calibre originally supplied as a pocket-watch movement and later widely re-used, undecorated or finished to order, in mechanical wristwatches valued for their visible, easily serviced construction.17 (base); higher-jewel and decorated versions exist jewels · Swiss lever · 36.6 mm (16½ lignes)Switzerland · 1974 to presentValjoux (ETA) 7750A cam-and-lever chronograph module integrated with an automatic base, designed for efficient volume production rather than for the finish of a column-wheel chronograph; briefly discontinued in the 1970s crisis and revived in the 1980s to become an industry-standard workhorse.25 jewels · Swiss lever · 30 mm (13¼ lignes)
Switzerland · 1969 to present, with interruptionsZenith El PrimeroAn integrated automatic chronograph running at an unusually high 36,000 vph, giving 1/10-second chronograph resolution; launched in 1969 in close competition with other automatic chronograph projects and narrowly escaped destruction during the quartz crisis.31 (typical) jewels · Swiss lever · Approx. 30 mm depending on generationSwitzerland · 1949 – 1968 (production), associated with the Speedmaster from 1957Omega Calibre 321A hand-wound column-wheel chronograph descended from Lemania's ébauche design, finished by Omega and fitted to the earliest Speedmaster references; qualified by NASA testing and worn during the Apollo 11 lunar surface activity.17 jewels · Swiss lever · Approx. 27 mm (12 lignes)
Switzerland · 1988 – c. 2015Rolex Calibre 3135A robust in-house self-winding calibre with a free-sprung, adjustable-mass balance, produced in very large numbers and forming the backbone of Rolex's core professional and dress models for over two decades.31 jewels · Swiss lever with Rolex's own pallet and escape-wheel production · Approx. 28.5 mmSwitzerland · 1967 – 1970s (as supplied); later revived under related referencesJaeger-LeCoultre Calibre 920An extremely thin automatic movement using a 22-carat gold peripheral micro-rotor rather than a full rotor, allowing exceptional slimness; supplied by Jaeger-LeCoultre to several prestige houses and adapted as the basis for celebrated in-house calibres elsewhere.Approx. 28 jewels · Swiss lever · Approx. 28 mmJapan · 1969 – mid-1970sSeiko Calibre 6139One of the earliest automatic chronograph calibres to reach the market, notable for its vertical clutch chronograph coupling and single push-button-free crown-based control layout in some references.17 or 21 depending on market version jewels · Swiss-type lever, Seiko manufacture · Approx. 27 mmSwitzerland · 1936 – 1950sLongines Calibre 13ZNA highly regarded pre-war and post-war column-wheel chronograph movement, valued by collectors for its finishing and its flyback function on certain references.Approx. 17–19 jewels · Swiss lever · Approx. 29 mm (13 lignes)Germany · 1994 to the mid-2000s (original Lange 1 calibre)A. Lange & Söhne Calibre L901.0The manual-wind movement introduced in the Lange 1, the flagship model of the relaunched A. Lange & Söhne after German reunification, notable for its asymmetric dial layout and dual-barrel long power reserve.Approx. 53 jewels · Swiss-type lever, in-house manufacture · Not fully documented in accessible sourcesUnited States · Late 1920s to the early 1930s, with assembly from parts continuing after the Hamilton purchaseIllinois Bunn Special (60-hour grades)Three-quarter plate railroad-grade movement with a long-running barrel arrangement marked for a 60-hour run, produced in the final independent years of the Illinois Watch Company.21 or 23 depending on grade jewels · Swiss lever with jewelled pallets · 16 size
United States · c. 1890s to the 1940s across successive modelsWaltham VanguardWaltham's top railroad grade, produced across several models and both 18 and 16 size, with high jewel counts, gold settings and heavy adjustment to position, temperature and isochronism.19, 21 or 23 depending on grade jewels · Lever, jewelled to the centre on the highest grades · 18 size early, 16 size in later productionUnited States · From the 1860s through the mid-twentieth century across many gradesElgin B. W. RaymondA grade name rather than a single calibre, applied by Elgin to railroad-standard movements for most of the company's history, so that examples differ fundamentally in plate layout between early key-wind and late twentieth-century production.15 to 23 depending on grade and date jewels · Lever · 18 size early; later 16 size and smallerEngland · c. 1700 to the late nineteenth centuryEnglish full-plate fusee movementA continuous top plate over the whole train, with a fusee and chain equalising mainspring torque and, on most examples, a pierced and engraved balance cock. The construction is the defining form of the English trade and the direct counterpart to the Continental bar movement.Unjewelled on plain work; jewelled to the escapement or more on better watches jewels · Verge on early work; English right-angle lever on nineteenth-century examples · Varies; generally large by Continental standardsSwitzerland · c. 1916 introduction, with production continuing for several decadesValjoux 23A column-wheel chronograph calibre with laterally coupled clutch, supplied as an ébauche to a very large number of brands and finished to their own standards.17 typical jewels · Swiss lever · Approx. 29.5 mm (13 lignes)Switzerland · c. 1937 onward, with production continuing into the 1970sLanderon 48A cam-and-lever (shuttle) chronograph rather than a column wheel, designed for simpler and cheaper manufacture and adjustment, and supplied in very large numbers across the mid-century chronograph trade.17 typical jewels · Swiss lever · Approx. 29.8 mmSwitzerland · 1930s onward, with the design later produced in the Soviet UnionCortébert Calibre 616A large, robust bridge-type hand-wound pocket calibre whose design was transferred to Soviet production after the Second World War, where it became the basis of an extremely long production run.15 to 18 depending on version jewels · Swiss lever · Approx. 36 mmSoviet Union (Chelyabinsk) · Second half of the twentieth centuryMolnija 3602A Soviet pocket-watch calibre derived from the Cortébert 616 design, produced in very large quantity at Chelyabinsk and widely used in both plain and presentation pocket watches.18 jewels · Swiss-type lever · Approx. 36 mmSwitzerland · 1971 onward, later produced within ETAPeseux 7001A very thin manual-wind wristwatch calibre with an open, easily accessible bridge layout, widely used in dress watches and extensively adopted as a teaching and modification base.17 jewels · Swiss lever · Approx. 23.3 mm (10½ lignes)Switzerland · 1970s onward, still in productionETA 2824-2A compact automatic calibre with a ball-bearing-mounted rotor and reversing wheels, supplied in several finishing grades from Standard to Chronometer and used by a very large number of brands.25 jewels · Swiss lever · Approx. 25.6 mm (11½ lignes)France · c. 1840 to the early twentieth centuryFrench round (Paris) clock movementTwo circular brass plates carrying the going and striking trains in a compact drum, made as a standardised unit by specialist movement factories in Paris and the Franche-Comté and sold to case makers across Europe.Generally unjewelled; some better movements jewelled at the escapement jewels · Brocot or plain deadbeat; recoil on cheaper work · Typically around 80 to 100 mm across the round platesAustria and later Germany · Early nineteenth century through the late nineteenth centuryVienna regulator movementA light, finely finished weight-driven movement between rectangular plates, designed to run on very little power in a slim glazed wall case, with high-grade examples approaching precision-regulator standards.Generally unjewelled; the finest examples jewelled at the escapement jewels · Deadbeat, with high-grade examples having jewelled pallets · Rectangular plates rather than a circular calibreUnited States (Lancaster, Pennsylvania) · Produced for military contracts from the early 1940sHamilton 4992BA high-grade 16-size American movement built to a navigational specification, with a centre-seconds train and a plain, service-oriented finish rather than decorative damascening.22 jewels jewels · Swiss lever · 16 sizeUnited States (Waltham, Massachusetts) · Late nineteenth century into the early twentieth centuryWaltham Riverside MaximusWaltham's top commercial grade, distinguished from ordinary Riverside grades by a higher jewel count, gold jewel settings, decorative finishing and closer adjustment.23 jewels on the standard specification jewels · Swiss lever, with gold centre wheel and raised jewel settings on the finest examples · Made in 16 size and 12 size, with earlier larger sizes recordedEngland · Company active from the 1890s until the early twentieth centuryLancashire Watch Company lever movementMachine-made English movements produced at Prescot in an attempt to answer American and Swiss factory competition with interchangeable parts rather than outworker handwork.Ranges from unjewelled trade grades to fully jewelled examples jewels · English lever, with Swiss-pattern work on some later grades · Several sizes made; individual dimensions not recorded in a source consulted hereSwitzerland (Geneva) · Introduced in 1977 and still in use in developed formsPatek Philippe calibre 240An ultra-thin automatic built around a recessed 22-carat gold micro-rotor rather than a full-diameter rotor, which keeps overall height low and leaves room for modules above the base movement.27 jewels on the base calibre jewels · Swiss lever · 27.5 mmSwitzerland · In use from the 1960s to the present in developed formsVacheron Constantin calibre 1120Vacheron Constantin's version of the ultra-thin automatic designed by Jaeger-LeCoultre as the 920, in which the rotor sits within the movement's outer diameter rather than above the plate.36 jewels jewels · Swiss lever · 28.4 mmSwitzerland (Saint-Imier) · Mid twentieth centuryLongines calibre 30CHAn in-house column-wheel chronograph made by Longines itself rather than bought from a specialist ébauche house, with a flat, legible layout and a single register.17 jewels on standard examples jewels · Swiss lever · 29.8 mmGermany (Glashütte) · From the mid 1990sA. Lange & Söhne calibre L921.4A three-quarter plate movement in German silver with gold chatons, blued screws and hand-engraved balance cock, laid out so that the asymmetric Lange 1 dial has each indication over its own mechanism.Not recorded in a source consulted here jewels · Swiss lever · Not recorded in a source consulted hereGermany (Schramberg) · Mid twentieth centuryJunghans calibre J83A German wristwatch calibre family made in grades from ordinary commercial work up to versions submitted for chronometer certification.Made in several jewel counts, including chronometer-grade versions jewels · Swiss lever · Not recorded in a source consulted hereFrance · Nineteenth centuryJapy Frères ébaucheRough movements made by machine in large quantities and sold unfinished to watch and clock establishers, who fitted escapements, jewelling, dials and cases.Supplied unjewelled or partly jewelled, to be finished by the buyer jewels · Supplied without escapement on many ébauches; cylinder and lever both common when finished · Supplied in many sizesFrance · Mid twentieth centuryLip calibre R25A French manual-winding wristwatch calibre from the Besançon factory, made in commercial grades for Lip's own watches.Made in several jewel counts jewels · Swiss-pattern lever · Not recorded in a source consulted hereJapan (Shizukuishi, Iwate) · From 1998Seiko calibre 9S55The mechanical calibre with which Seiko resumed high-grade mechanical production at the Shizukuishi studio, assembled and adjusted by hand to an in-house accuracy specification stricter than the standard chronometer test.26 jewels jewels · Swiss lever with Seiko's own Spron hairspring material · 28.4 mmJapan · From 1983Seiko calibre 7A28The first analogue quartz chronograph movement, using three separate stepping motors so that the chronograph hands run independently of the timekeeping train and can be reset instantly.15 jewels jewels · None; quartz oscillator with stepping motors · Not recorded in a source consulted hereMore tools
Other identification & study tools
IdentificationPocket Watch IdentifierA step-by-step workflow for narrowing an unknown watch or clock by object type, movement, markings and numbers.HistoryTimelineA chronological timeline of horological milestones, from early mechanical clocks to modern precision standards.MechanismsEscapement ExplorerCompare verge, cylinder, lever, deadbeat and other escapements on principle, advantages and drawbacks.DiagramsAnatomy Explorer & Diagram PlatesTwelve labelled schematic plates, from pocket watch anatomy to calendar work, each part linked to its explanation.ReferenceGlossary ExplorerA searchable glossary of horological terminology, cross-referenced to every other part of the site.StudyWatchmaking AcademyThe structured curriculum these tools are designed to accompany, from first principles to advanced technique.
Gear train
Gear Train Simulator
An animated going train from barrel to escape wheel, with a speed control and a live relative-rotation-rate readout for each stage.
Relative rotation rate is shown as a multiple of the barrel's own rate; each stage turns faster than the last because fewer teeth complete a rotation sooner for the same driving motion.
Escapement
Escapement Animation
The lock / impulse / detached-swing cycle of a lever escapement, animated and explained step by step.
Impulse — the escape wheel tooth is unlocking and delivering impulse through the pallet fork to the balance.
Ticks elapsed: 0. The escape wheel only advances during the brief impulse window near each zero-crossing of the balance's swing; the rest of the cycle it is locked and the balance swings under its own stored energy, which is what makes a lever escapement "detached".
Anatomy
Anatomy Explorer
The same labelled, hotspot-driven explorer used throughout the Diagrams hub, shown here with the pocket watch variant.
Pocket watch anatomy
Case
The outer housing that protects the movement and dial.
See the Diagrams hub for the full set of twelve labelled plates.