Bulova 1950 Duo Wind

12/10 votes
Model ID rating explained.
2.5875
Manufacture Year: 
1950
Movement Model: 
11AAC
Movement Jewels: 
17
Case Serial No.: 
2949575
Case shape: 
Round
Case Manufacturer: 
Bulova
Gender: 
Mens
Additional Information: 

Fancy Cased Automatic measures 40mm lug to lug x 33mm non inclusive of the Crown using Calipers.

Original Butler finish Dial shows a combination of applied Gilt hashmarks and Arabic numerals. Hour and Minute hands are Gilt Alpha style, Sweep center seconds hand is Gilt Modern style. Bulova logo is applied Gilt, Duo Wind insignia is printed Black, Black printed track is numerically calibrated at 5 Second intervals.

Crown is original.

Snap fit Caseback is Stainless Steel and stamped as shown.

1950 was the first Year an Automatic movement in a Bulova.

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OldTicker
Posted June 10, 2012 - 11:35am

Movement has the L0 date code or is it L8?,  what about the case?? The 11 series movement starts to show up about 1955 in the movement database, the rest of the Duo-winds use a 10 series movement.

It sure matches the Thayer ad better than the Duo-wind ad...2 Stars on the Duo-wind ID.

FifthAvenueRestorations's picture
FifthAvenueRest...
Posted June 10, 2012 - 3:13pm

L0 Movement.

L0 Case.

The 'DUO WIND's listed in the database post 1952 (10 linge) are obviously the 'THAYER'.

jeesh...do Your Homework people.

 

NOVA
Posted June 10, 2012 - 3:24pm

OT, very interesting point about the 11 series not being seen before 1955.  My collection confirms that as well.   I just checked Ranfft, and he also lists nothing for the Bulova 11 series before 1955.

 

FifthAvenueRestorations's picture
FifthAvenueRest...
Posted June 10, 2012 - 4:30pm

Very interesting, as the Bulova 11 AAC is based on the Swiss Felsa 415 Bidynator.

http://www.ranfft.de/cgi-bin/bidfun-db.cgi?10&ranfft&&2uswk&Felsa_410

Circa 1946.

* edit: 1942, according to Dr Ranffts site.

My bad.

 

Remarks
1942
first calibre with bidirectional rotor winding, pilot series for the family 690...699 with almost the same base-plate, even samples with caledar corresponding the 693 are known.

 

The Bulova 9 AB and 10 AU are also Felsa based Swiss automatics.

 

William Smith's picture
William Smith
Posted June 10, 2012 - 4:30pm

Club 5000Panel Member

Mark...it's more difficult to do our homework now because we have so much more information available.  But with Ranfft's site, this site, and NOVA's site -plus the new ads we have- our homework can be more productive once done.  I think it's great we have all these resources available.  We can not only say so much more now vs a year ago, but we can also cite the reasons we are saying these things. 

Your link to Ranfft above does not address the years when the 11 series is introduced (nor the 10 series) but only referrers to the Felsa bidiator technology.  This wasn't clear to me from your post without going to the link you provided.  Thanks for posting the link.

FifthAvenueRestorations's picture
FifthAvenueRest...
Posted June 10, 2012 - 5:47pm

1950

 

1950 - Note the solid rotor and the slot with the arrow below the rotor axle jewel (?)

Sorry I'm not a Watchmaker,.... but I do know a 'DUO WIND' when I see one.

 

William Smith's picture
William Smith
Posted June 10, 2012 - 6:18pm

Club 5000Panel Member

...and now it's more clear....and an L0 -so a new entry to the movement database for all.  (If Dr Ranfft frequents our site to find out).  Thanks Mark....pic says it all...

FifthAvenueRestorations's picture
FifthAvenueRest...
Posted June 11, 2012 - 8:48am

 

..........  ~crickets~

NOVA
Posted June 11, 2012 - 8:58am

So?  We have an early example of an 11 series movement. 

No one ever disputed that the watch is a duo-wind, just what it should be called, since we have ads naming the duo-wind the Thayer.

The closest matching ad names this watch the Thayer, and nothing presented to date has shown that the new ad is not the best available evidence of what this watch should be called.

"Duo-Wind" may have only ever been a generic descriptive name used in third-party ads for this duo-wind and self-winding model.  The only Bulova-produced ad we have for this watch names it the Thayer and includes Duo-Wind on the dial, just like the subject watch.  Nothing about that fact has changed.

JP
Posted June 11, 2012 - 10:28am

Panel Member

The slot below the rotor axel jewel is the release mechanism for the rotor. It is the only way to  remove the rotor that I am aware of.

John JP