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Durowe 440
Manual · 10.5‴ · Germany · 1956
Dimensions
23.7 mm
Height
3.65mm
Jewels
21
Power reserve
36h
Timegrapher
Beat rate
18,000bph
Frequency
2.5Hz
Lift angle
56°
Reference: healthy amplitude ≈ 270–315° fully wound (>200° at 24 h); beat error ideally < 0.5 ms.
Movement
| Movement type |
Manual
Purely mechanical movements wound by hand via the crown, which tensions the mainspring to store energy. As the spring unwinds, it drives the gear train at a controlled rate set by the escapement and balance. Typical power reserves range from 38 to 80 hours, requiring daily or near-daily winding to keep the watch running.
|
|---|---|
| Winding type |
Stem Winding (Crown)
Winding the mainspring by turning the crown attached to the stem, transmitting torque through the winding pinion. Patented by Adrien Philippe in 1842, it replaced key winding and remains the standard manual winding method for both pocket watches and wristwatches.
|
| 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.
|
Specifications
| Lignes | 10.5‴ |
|---|---|
| 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.
|
| Hand count | 3 |
| Hand sizes | 1.30 x 0.80 x 0.22mm |
| Further measures | Mounting Diameter (Dm): 23.3mm Stem height (T): 1.9mm Mounting Height (F): 1.0mm |
Origin & References
| Manufacturer | Durowe |
|---|---|
| Country | Germany |
| Launch year | 1956 |
| COSC certified | No |
| Signature | ca. 1960: Laco, 21 Jewels - 7; Duro-Swing |
Notes
Remarks: 1956-
Other data: balance staff: U2243 stem: W2404 / W2875 thread 1.1mm/0.9mm mainspring / battery: Zf682, 1.20 x 9.5 x 0.105 x 300mm balance staff ronda: 4120 (10,5) stem ronda: 1116 (10,5) stem ronda: 1428 (10,5) Mainspring: 1.200 x 9.000 x 0.105 x 300.000 mm
Ranfft mentioned about this caliber: There are variants with this quantity of jewels 17, 21
Other data: balance staff: U2243 stem: W2404 / W2875 thread 1.1mm/0.9mm mainspring / battery: Zf682, 1.20 x 9.5 x 0.105 x 300mm balance staff ronda: 4120 (10,5) stem ronda: 1116 (10,5) stem ronda: 1428 (10,5) Mainspring: 1.200 x 9.000 x 0.105 x 300.000 mm
Ranfft mentioned about this caliber: There are variants with this quantity of jewels 17, 21
Family
Series 440 - suffix -1
10.5" :
440: manual wind
443: manual wind, small date
445: manual wind, modified bridge shapes
10.5" , balance like successor family 450ff:
441: manual wind
446: manual wind, modified bridge shapes
11.5" :
540, 542: manual wind
570: automatic
580: automatic, small date
585: manual wind, normal date
590: automatic, normal date
suffix -1: ring balance, no regulator pointer
440: manual wind
443: manual wind, small date
445: manual wind, modified bridge shapes
10.5" , balance like successor family 450ff:
441: manual wind
446: manual wind, modified bridge shapes
11.5" :
540, 542: manual wind
570: automatic
580: automatic, small date
585: manual wind, normal date
590: automatic, normal date
suffix -1: ring balance, no regulator pointer
Related calibers
Durowe 440
Durowe 441
Durowe 443
Durowe 445
Durowe 446
Durowe 540
Durowe 542
Durowe 570
Durowe 570/1
Durowe 580
Durowe 585
Durowe 590
Durowe 590/1
Compatible Parts
1,439 other catalog sources can supply compatible parts for this caliber.
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