Groeflin Walter and Hans Grovana Biel Age determination
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Origin and background
Point
information
Brand name:
Gröflin / Groeflin (Switzerland)
Location:
presumably Basel or Biel (Bienne) – registered in the commercial register since around the 1920s
Task:
Assembler / Assembly plant — Watch manufacturing with purchased movements from A. Schild (AS), FHF, ETA, Unitas
Production time:
ca. 1920 – 1970
Typical products:
Pocket watches, automatic and manual winding watches, occasionally chronographs
Signature:
“Gröflin – Swiss Made” or “Groeflin – Swiss” on dial or movement bridge
Serial numbers and caliber origin
Since the company did not manufacture its own blanks, each serial number comes from the manufacturers of the respective ébauches. This is an advantage – one can estimate the age based on known series production ranges of the factory manufacturers:
Serial number (approx.)
Factory / Manufacturer
Production period
Remarks
100,000 – 250,000
Aegler / Rebberg
1910 – 1925
Early pocket watches, silver cases
250,000 – 500,000
A. Schild AS 340 / 400
1925 – 1938
Manual winding, 15 jewels
500,000 – 800,000
AS 970 / FHF 29 / Unitas 30
1938 – 1955
Wristwatches, steel/nickel case
800,000 – 1,100,000
AS 1130 “Wehrmachtswerk” / ETA 1080
1950 – 1965
Small series of military or civilian models
> 1,100,000
AS 1686 / ETA 2452
ca. 1965 – 1975
Late automatic models
Dial and design notes for dating
feature
Temporal assignment
Enamel dial, Roman numerals
1920 – 1935
Arabic numerals, small seconds at 6 o'clock
1930 – 1945
Luminous numerals (radium)
from 1935
“Shockproof / Antimagnetic / Swiss Made” Printed
from 1940
Central seconds hand + Breguet hands
1945 – 1955
Automatic inscription / Rotor
from 1952
Stainless steel case (with “Stainless Steel Back”)
