Felsa 351

Basic Information

NameFelsa 351
Alternative NameAlpina 630
ManufacturerFelsa
Launch Year1945
Caliber FamilyDescription
350: sub second. 9"
351, 352, 358: sub second
359, 360: sweep second

longer mainspring, new setting-lever spring:
720...722: sub second
725, 726: sweep second

Related calibers
Felsa 350, Felsa 351, Felsa 352, Felsa 358, Felsa 359, Felsa 360, Felsa 720, Felsa 721, Felsa 722, Felsa 725, Felsa 726
Is COSC certifiedNo
Timegrapher
Beat rate
18,000 bph
Frequency
2.5 Hz
Lift angle
52 degrees

Reference: healthy amplitude ≈ 270–315° fully wound (>200° at 24 h); beat error ideally < 0.5 ms.

Technical Details

Lignes Dimensions8.75 ‴
Dimensions19.7 mm
Height3.3 mm
Further MeasuresMounting Diameter (Dm): 19.4mm
Stem height (T): 1.7mm
Mounting Height (F): 0.5mm
Power Reserve36 hours
Frequency18,000 vph
Jewels15
Lift Angle52 degrees

Complications and Specifications

ShapeRound
Complications
  • Sub Second
  • Moon Phase
Regulator TypePinned Regulator (or Index Regulator)
Movement TypeManual
Escapement TypeSwiss Lever
Control TypeBalance Wheel
Winding TypeStem Winding (Crown)
Setting TypeStem Set (Crown Pull)

Additional Information

Hand Sizes1.20 x 0.60 / 0.18mm
Hand Count3
Country Of ManufactureSwitzerland
NotesRemarks: For the generation 350... two different setting-lever springs are available, but they are interchangable.
differences not known between 351, 352, 358
Other data: balance staff: U537 stem: W137 mainspring / battery: Zf1013, 1.40 x 7.5 x 0.08 x 250mm balance staff ronda: 3016 (8,75) balance staff ronda: 995 (9) stem ronda: 76 (8,75) Mainspring: 1.400 x 7.000 x 0.080 x 240.000 mm
Signatureca. 1945: Felsa 351, 630 - Felsa 350 (Alpina 630, Felsa 351)

Compatible Parts

638 other caliber(s) share compatible parts with this caliber.

58 compatible part(s) available — Supporter feature.

Metadata

Created AtSep 15, 2023
Updated AtMay 26, 2026, 4:43:49 AM
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