CALIBER/browser
CORPUS EXPORT · 12269 calibers · 59387 family views · round round/2026-09-08Compiled from app/public/data/ · corpus 70c0140eba.
Family treeBulova 7AP (ETA 735) — Heritage family: 8 calibers, 7 sourced lineage links.Drag to explore.
100%drag to pan · hover a caliber to isolate its line · scroll the page normallyopen the full family view →
ébauche ofébauche ofébauche ofébauche ofébauche ofébauche ofébauche ofBulova 7AA (ETA 735) — open caliber pageBulova 7AA (ETA 735)1947maker not sourc…1 exec · grade ?Bulova 7AH (ETA 735) — open caliber pageBulova 7AH (ETA 735)1928maker not sourc…1 exec · grade ?Bulova 7AK (ETA 735) — open caliber pageBulova 7AK (ETA 735)1936maker not sourc…1 exec · grade ?Bulova 7AN (ETA 735) — open caliber pageBulova 7AN (ETA 735)—maker not sourc…1 exec · grade ?Bulova 7AP (ETA 735) — the caliber this page is aboutBulova 7AP (ETA 735)1936maker not sourc…1 exec · grade ?Dugena 839 (ETA 735) — open caliber pageDugena 839 (ETA 735)—maker not sourc…1 exec · grade ?ETA 735 — open caliber pageETA 735—ETA SA Manufacture Horlogère…1 exec · grade ?Silvana 7775 (ETA 735) — open caliber pageSilvana 7775 (ETA 735)—maker not sourc…1 exec · grade ?
accepteddisputed
Sense of “family”Heritage · 8Everything (debug) · 8Parts cluster (Jules Borel sense) · 1Manufacturer-internal (Ranfft sense) · 1Based-on star (WatchBase sense) · 8Open the full family view →

movement

Bulova 7AP (ETA 735)

maker not sourcedintroduced 1936design:bulova-7apcompare specs · 2
bounding evidence — no range is drawn on the era axis
not after 1940
a dated example movement, 1940“1-3) 1940: Bulova Watch Co, U.S.A, Adjusted, 17 Jewels”
not after 1940
a dated example movement, 1940“1-2) 1940: Bulova Watch Co, U.S.A, Adjusted, 17 Jewels”
not after 1943
a dated example movement, 1943“3-4) 1943: X (1943), Bulova Watch Co, U.S.A, 21 Jewels”
not after 1943
a dated example movement, 1943“4-5) 1943: X (1943), Bulova Watch Co, U.S.A, 21 Jewels”

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
Bulova 7AP (ETA 735)
movement
IIDesignations — 0 names

No designation is recorded for this design yet.

IIIExecutions — 1 article

No source in this corpus states which grade any Bulova 7AP (ETA 735) 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:bulova-7ap/unknown

Specifications

PropertyValueScopeStatusSources
Jewels
build.jewel_count
17Ranfft data sheet, the 17-jewel member of its 17/21 rangestaged
Jewels
build.jewel_count
21Ranfft data sheet, the 21-jewel member of its 17/21 rangestaged
Movement shape
build.shape
rectangular—staged
Seconds display
disp.seconds_display
small—staged
Movement height
geom.height_mm
3.55 mm—staged
Frequency
osc.frequency_vph
18000 vph—staged
Power reserve (typical)
power.reserve_typical_h
47 h—staged
Discontinued
prod.discontinued_year
1944—staged
Introduced
prod.intro_year
1936—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 · 1

Where this construction came from. Read up the arrows.

Descendants · 0

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

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

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/20181106115509/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Bulova_7AP
    archivetier 2retrieved 2018-11-0613 facts on this page
  2. 2
    Internet Archive
    https://web.archive.org/web/20181106115503/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Bulova_7AN
    archivetier 2retrieved 2018-11-063 facts on this page
  3. 3
    Internet Archive
    https://web.archive.org/web/20230906043506/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Bulova_7AA&
    archivetier 2retrieved 2023-09-061 fact on this page
  4. 4
    Internet Archive
    https://web.archive.org/web/20181106115451/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Bulova_7AH
    archivetier 2retrieved 2018-11-061 fact on this page
  5. 5
    Internet Archive
    https://web.archive.org/web/20181106115457/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&a0&2uswk&Bulova_7AK
    archivetier 2retrieved 2018-11-061 fact on this page
  6. 6
    Internet Archive
    https://web.archive.org/web/20230907064335/http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Dugena_839&
    archivetier 2retrieved 2023-09-071 fact on this page
  7. 7
    Internet Archive
    https://web.archive.org/web/20230901232917/http://ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&0&2uswk&Silvana_7775
    archivetier 2retrieved 2023-09-011 fact on this page