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Tissot 27B-621
Manual · 12‴ · Switzerland · 1950
Dimensions
27 mm
Height
5.70mm
Jewels
16
Power reserve
44h
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.
|
| Shock protection |
Incabloc
The most famous and widely used shock protection system in horology. Invented in 1934 by Georges Braunschweig and Fritz Marti at Universal Escapements (La Chaux-de-Fonds), it employs a lyre-shaped spring holding the jewel setting, allowing it to shift under impact and return to position. Adopted by countless Swiss makers across the 20th century.
|
Specifications
| Lignes | 12‴ |
|---|---|
| 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 | 1.40 x 0.80 x 0.20mm |
| Further measures | Mounting Diameter (Dm): 26.5mm Stem height (T): 2.6mm Mounting Height (F): 1.6mm |
Origin & References
| Manufacturer | Tissot |
|---|---|
| Country | Switzerland |
| Launch year | 1950 |
| COSC certified | No |
| Signature | 1958: 4283555, Chs. Tissot & Fils, Swiss, 16 Jewels; Incabloc |
| US import codes |
|
Notes
Remarks: 1950-1961
early samples with regulator pointer (cf. 27B-21)
Other data: balance staff: U2009 INC stem: W2229 mainspring / battery: 1.70 x 10.0 x 0.12mm balance staff ronda: 3915 (12) stem ronda: 1215 (12)
early samples with regulator pointer (cf. 27B-21)
Other data: balance staff: U2009 INC stem: W2229 mainspring / battery: 1.70 x 10.0 x 0.12mm balance staff ronda: 3915 (12) stem ronda: 1215 (12)
Family
Series 27 - 27B-9
baseplate plane:
27 : sub second
27-1 : sub second, Incabloc
27-3 : sub second, Shock Resist
27-2: sweep second
27-23 : sweep second, Shock Resist
27-53: chronograph 60s, Shock Resist
27-63: sub second, date, Shock Resist
baseplate bevelled, setting-lever spring modified:
27-T : sub second
27-1T: sub second, Incabloc
27-2T: sweep second
27-21T: sweep second, Incabloc
27-61T: sub second, date, Incabloc
complete redesign:
27B : sub second
27B-1 : sub second, Incabloc
27B-2 : sweep second
27B-21: sweep second, Incabloc
27B-61: sweep second, date, Incabloc
27B-9: no second
27 : sub second
27-1 : sub second, Incabloc
27-3 : sub second, Shock Resist
27-2: sweep second
27-23 : sweep second, Shock Resist
27-53: chronograph 60s, Shock Resist
27-63: sub second, date, Shock Resist
baseplate bevelled, setting-lever spring modified:
27-T : sub second
27-1T: sub second, Incabloc
27-2T: sweep second
27-21T: sweep second, Incabloc
27-61T: sub second, date, Incabloc
complete redesign:
27B : sub second
27B-1 : sub second, Incabloc
27B-2 : sweep second
27B-21: sweep second, Incabloc
27B-61: sweep second, date, Incabloc
27B-9: no second
Related calibers
Tissot 27
Tissot 27-1
Tissot 27-1T
Tissot 27-2
Tissot 27-21T
Tissot 27-23
Tissot 27-2T
Tissot 27-3
Tissot 27-61T
Tissot 27-63
Tissot 27-T
Tissot 27B
Tissot 27B-1
Tissot 27B-2
Tissot 27B-21
Tissot 27B-621
Tissot 27B-9
Compatible Parts
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