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Longines 431
Automatic · 11.5‴ · Switzerland · 1967
Dimensions
26 mm
Height
4.90mm
Jewels
25
Power reserve
40h
Timegrapher
Beat rate
36,000bph
Frequency
5Hz
Lift angle
52°
Reference: healthy amplitude ≈ 270–315° fully wound (>200° at 24 h); beat error ideally < 0.5 ms.
Movement
| Movement type |
Automatic
Mechanical movements fitted with an oscillating rotor that winds the mainspring through the wearer's natural motion. Invented by Abraham-Louis Perrelet around 1777 for pocket watches and adapted to the wristwatch by John Harwood in 1923, it combines traditional craftsmanship with everyday convenience.
|
|---|---|
| Winding type |
Automatic (Rotor-Driven)
Self-winding via a rotor whose motion winds the mainspring through a transmission gear train. The specific rotor configuration (central, micro, peripheral, bumper) is catalogued separately under Rotor Type. Standard on the vast majority of mechanical wristwatches since the mid-20th century.
|
| Setting type |
Stem Set (Crown Pull)
The dominant modern system: pulling the crown out to a setting position engages the hand-setting mechanism. Introduced in the late 19th century and refined into multi-position crowns (date, time, GMT). Used in virtually all modern wristwatches and most 20th-century pocket watches.
|
| Escapement type |
Swiss Lever
The undisputed standard of modern mechanical watchmaking. Through an elegant interplay between escape wheel, pallet fork, and balance, it delivers reliable impulses with the safety of 'draw' to keep the lever locked. Refined since the 18th century, it powers almost every quality mechanical wristwatch made today.
|
| Control type |
Balance Wheel
The heart of mechanical timepieces, the balance wheel is an oscillating component that, together with the hairspring, forms a harmonic oscillator regulating the gear train's pace. Its steady back-and-forth motion ensures the even release of energy from the mainspring, governing the watch's accuracy.
|
| Regulator type |
Pinned Regulator (or Index Regulator)
The most traditional regulator, consisting of a movable index pointer fitted with two curb pins (or a pin and a boot) that embrace the hairspring. Sliding the index along its scale changes the spring's active length, adjusting the rate. Simple, reliable, and easy to service, it remains the workhorse standard across countless mechanical movements.
|
| Rotor type |
Central Rotor
The most common automatic winding rotor, mounted on the central axis of the movement and rotating a full 360°. Industrialized by Rolex with the Perpetual system in 1931 and refined throughout the 20th century, it offers excellent winding efficiency and remains the de facto standard for automatic wristwatches, whether winding in one or both directions.
|
| Shock protection |
KIF
A family of Swiss shock protection systems (Trior, Flector, Elastor, Duofix, Protechoc) produced by Parechoc SA, the main competitor to Incabloc. Uses a multi-point elastic spring design (typically three points in the Trior version) that excels in thinner calibres. Long favoured by Rolex (Duofix), Patek Philippe, and Audemars Piguet before each developed proprietary systems.
|
Specifications
| Lignes | 11.5‴ |
|---|---|
| Shape |
Round
It is the most common form that we can find.
|
| Complications |
Sweep Second
Contrary to the ticking motion of quartz watches, the sweep second hand in mechanical watches moves smoothly around the dial, offering a visual representation of time flowing continuously. This has become synonymous with the precision and craft of mechanical horology.
,
Date
An essential for many, the date display reminds wearers of their daily commitments, connecting the abstract concept of time to tangible daily events.
|
| Hand count | 3 |
| Hand sizes | 1.50 x 0.90 x 0.21mm |
| Further measures | Mounting Diameter (Dm): 25.6mm Ball Bearing: 0.1mm Stem height (T): 2.0mm Mounting Height (F): 1.7mm |
Origin & References
| Manufacturer | Longines |
|---|---|
| Country | Switzerland |
| Launch year | 1967 |
| In-house | No |
| COSC certified | No |
| Signature | 1-3) 1970: 50190196, Longines, Longines Watch Co, Swiss, 17 Jewels; Kif-Ultraflex
4) 1970: 50371798, Longines, Longines Watch Co, Swiss, 36'000, Adjusted 4 Positions and Temperature, 25 Jewels; Kif-Ultraflex |
| US import codes |
Notes
Remarks: 1967-
Other data: balance staff: U3308 stem: W3253 mainspring / battery: 1.00 x 10.0 x 0.13mm stem ronda: 2319 (11,5)
Ranfft mentioned about this caliber: There are variants with this quantity of jewels 17, 25
Other data: balance staff: U3308 stem: W3253 mainspring / battery: 1.00 x 10.0 x 0.13mm stem ronda: 2319 (11,5)
Ranfft mentioned about this caliber: There are variants with this quantity of jewels 17, 25
Family
Series 430 - 6652
36000 A/h, excenter regulator:
430: sweep second
431: sweep second, date
432: no second
433: no second, date
28800 A/h, micrometer regulator:
6641: sweep second, 25 jewels
6642: sweep second, 17 jewels
6651: sweep second, date, 25 jewels
6652: sweep second, date, 17 jewels
430: sweep second
431: sweep second, date
432: no second
433: no second, date
28800 A/h, micrometer regulator:
6641: sweep second, 25 jewels
6642: sweep second, 17 jewels
6651: sweep second, date, 25 jewels
6652: sweep second, date, 17 jewels
Related calibers
Longines 430
Longines 431
Longines 432
Longines 433
Longines 6641
Longines 6642
Longines 6651
Longines 6652
Compatible Parts
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