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Helvetia 820
Manual · 10.5‴ · Switzerland · 1950
Dimensions
23.7 mm
Height
4.95mm
Jewels
17
Power reserve
40h
Timegrapher
Beat rate
18,000bph
Frequency
2.5Hz
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.
,
Chronograph Stopwatch
Functionality meets style as this feature allows wearers to measure specific time intervals, embodying the blend of everyday utility with sophisticated design.
|
| Hand count | 3 |
| Hand sizes | 1.35 x 0.90 x 0.28mm |
| Further measures | Mounting Diameter (Dm): 23.3mm Stem height (T): 1.9mm Mounting Height (F): 1.2mm |
Origin & References
| Manufacturer | Helvetia |
|---|---|
| Country | Switzerland |
| Launch year | 1950 |
| COSC certified | No |
| Signature | ca. 1950: HXW, Helbros Watch Co, Swiss, 17 Jewels - 1635; Helvetia-Shock-Absorber
(Helvetia 820B, 11.5" , plane base plate) |
| US import codes |
Notes
Remarks: late samples with Kif-Duofix combined settings for escapement wheel
Other data: balance staff: U1448 stem: W1180 mainspring / battery: Zf1321, 1.60 x 9.5 x 0.095 x 330mm balance staff ronda: 1239 (10,5) stem ronda: 37 (11,5) Mainspring: 1.600 x 9.000 x 0.100 x 300.000 mm
Other data: balance staff: U1448 stem: W1180 mainspring / battery: Zf1321, 1.60 x 9.5 x 0.095 x 330mm balance staff ronda: 1239 (10,5) stem ronda: 37 (11,5) Mainspring: 1.600 x 9.000 x 0.100 x 300.000 mm
Family
Series 80 - suffix C
80: 11.5" , sub second
820: 10.5" , sub second
800: 11.5" , sweep second
820: 10.5" , sweep second
800: 11.5" , sweep second, plane base plate
suffix C: two screws for crown wheel
820: 10.5" , sub second
800: 11.5" , sweep second
820: 10.5" , sweep second
800: 11.5" , sweep second, plane base plate
suffix C: two screws for crown wheel
Related calibers
Helvetia 80
Helvetia 800
Helvetia 800C
Helvetia 80C
Helvetia 82
Helvetia 820
Helvetia 820B
Helvetia 820C
Helvetia 82C
Compatible Parts
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