CORPUS EXPORT · 12269 calibers · 59387 family views · round round/2026-09-08Compiled from app/public/data/ · corpus 70c0140eba.
Family treeETA 640 — Heritage family: 2 calibers, 1 sourced lineage link.Drag to explore.
accepteddisputed

movement

ETA 640

ETA SA Manufacture Horlogère Suissearchive filing⟨1950 or earlier⟩ range onlydesign:eta-640compare specs · 2
⟨1950 or earlier⟩ range only — no source gives an introduction yearread from sources · staged
not after 1950
a dated example movement, ca. 1945 (+5 yr, the source says “circa”)“ca. 1945: 83102, Benrus Watch Co, Model M, Swiss, Shockproof Pat'd, 7 Jewels; Benrus”

Identity

A caliber is three separate things and this reference keeps them apart: the construction, the names it is sold under, and the article a brand actually bought. A watch model points at an execution — never at a bare construction — which is why “same caliber” is almost never a complete answer.

IDesign — the construction
ETA 640
movementproducer: ETA SA Manufacture Horlogère Suissearchive filing
IIDesignations — 0 names

No designation is recorded for this design yet.

IIIExecutions — 1 article

No source in this corpus states which grade any ETA 640 was bought at. That unknown is stored as a real row rather than left blank, so it can be counted, filtered and excluded from any comparison that would otherwise assume parity.

unknownsynthetic
evidence: unknown

no source states which grade this article was bought at — this row exists so 'unknown' stays countable instead of becoming an assumption

exec:eta-640/unknown

Specifications

PropertyValueScopeStatusSources
Jewels
build.jewel_count
7Ranfft data sheet, the 7-jewel member of its 7/15 rangestaged
Jewels
build.jewel_count
15Ranfft data sheet, the 15-jewel member of its 7/15 rangestaged
Seconds display
disp.seconds_display
small—staged
Movement diameter
geom.diameter_mm
26.6 mm—staged
Frequency
osc.frequency_vph
18000 vph—staged
Winding mode
wind.mode
manual—staged

Where a property carries more than one value, the values have different scopes — an official spec sheet and observed hardware, say. Different scopes are not a disagreement, so both are accepted and both are shown with the scope they apply to.

Lineage

The same relationships as the tree at the top of this page, with their sources. An absence in a column means no source stated one.

Ancestors · 0

Where this construction came from. Read up the arrows.

None recorded. An absence here means no source stated one, not that none exists.

Descendants · 1

What came from it — revisions, variants, clones, licensed copies.

Related · 0

Stored in a different table from descent. A successor is not a child.

None recorded. An absence here means no source stated one, not that none exists.

Sources

  1. 1
    Internet Archive
    https://web.archive.org/web/20181107100848/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&ETA_640
    archivetier 2retrieved 2018-11-078 facts on this page
  2. 2
    Internet Archive
    https://web.archive.org/web/20230905101845/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Benrus_M&
    archivetier 2retrieved 2023-09-051 fact on this page