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Mido 500A
Manual · 5.5‴ x 7‴ · Switzerland · 1955
Also known as: AS 976
Dimensions
12.2 mm x 15.85 mm
Height
3.50mm
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.
|
| 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 | 5.5‴ x 7‴ |
|---|---|
| Shape |
Rectangle
Popular in dress watches and certain iconic wristwatch brands.
|
| Hand count | 2 |
| Hand sizes | 1.00 x 0.55mm |
| Further measures | Mounting Diameter (Dm): 12.2 x 15.5mm Stem height (T): 1.7mm Mounting Height (F): 0.5mm |
Origin & References
Notes
Other data: balance staff:
U1181
stem:
W967
mainspring / battery:
Zf994, 1.40 x 6.0 x 0.06 x 210mm
generations:
500: without shock protection
500A: Incabloc
balance staff ronda: 1687 (5 x 7)
Compatible Parts
1,390 other catalog sources can supply compatible parts for this caliber.
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