Would need an advice about a Speedmaster 321 crown (A1)

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befobe

·Aug 11, 2019

Hello OF,
Very new on OF, and impressed by the huge amount of infos here... I have a naive question: I have a B2 crown on my 145.012, and would be interested in mounting an A1, the "right" one (narrow omega, 24 teeth). I see this on the bay, but I wonder if it is correct for a speedy, since the seller displays only Seamaster ref.
Outer dimensions seem correct (Diam 6.75mm, thickness 3.8mm), but I guess the backside of the crown is important to mount it... Does the "seamaster 300 crown" could fit on the 321 of a 145.012?...

https://www.ebay.fr/itm/Vintage-Ome...Big-Crown-2913-14755-165014-Part/123758216400

Would you have an opinion about that?
Sincerly.
B.

 

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Speedmasterfan88

·Aug 11, 2019

This looks like a replica crown to me.

The original vintage omega crowns were constructed in a different way. They are not flat/smooth surfaced on the backside. The thin metal/ chromed outer layer was cramped over the base metal crown and „folded/hammered“ down on the back side, giving the impression of a row of little triangles when viewed from the back.

I‘ve only seen replica and modern service crowns with a smooth surface on the back side.

Maybe someone with more knowledge can chime in here.

Cheers,

Max

Edit:
Compare to this one please, Vintage flat floot which came from an early 60‘s Speedmaster:

Edited: Aug 11, 2019

 

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S.H.

·Aug 11, 2019

I do no think the one shown in the ebay ad are originals. I have a few, they look like this:

https://omegaforums.net/threads/a1-flat-foot-crowns-x3-1153-138-bracelet.96213/

Also beware of the thread.

 

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befobe

·Aug 11, 2019

Oh thanks for the pictures; the backside is indeed very, very different... (the front side is on the contrary very similar...! the logo is really... beautiful to me... good replica !)
And of course no mean to know if my crown axis will "screw" in this crown...
So, I'd better wait... until I see one FS here!...
Thanks again.
B.

 

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boogedyboo

·Aug 11, 2019

I am normally wary of the originality of any listing with the word “Replacement” in it.

 

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Larry S

·Aug 11, 2019·Color Commentator for the Hyperbole.

Good thread....I too have a later replacement crown on my 2998-6...It’s a mine field out there. Do no harm is now my motto....The watch was serviced as is and running well...I’m not meddling anymore.

 

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befobe

·Aug 11, 2019

boogedyboo

I am normally wary of the originality of any listing with the word “Replacement” in it.

I see... "replacement" does not match with "vintage"... meaning the ad is a little bit confusing... (I'm polite...).
Good reflex to have 😀

 

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Patrik83

·Aug 11, 2019

I’m not entirely an expert on the vintage Seamaster crown but from observations the Speedmaster has the “steam fitting” (can’t come up with a better explanation) pointing out from the back of the crown. The seamster crown “steam fitting” is not pointing out of the back but instead level with the back.

The Seamaster crown, as I understand it, can be modified to fit a Speedmaster.

Speedmaster:


Seamaster:

 

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befobe

·Aug 11, 2019

Okay, nice comparison. Means that the so called replacement part for Seamaster of the bay looks like more to a speedy version... Since the fitting is "higher" than the backside surface of the crown... More and more confusing this ad...

Concerning the answer of Larry S, due to my low English level, I'm not sure to catch the meaning of its last sentence...👎

 

S

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Stuie

·Aug 12, 2019

An A1 flat foot 24-tooth Speedmaster crown with the early skinny Omega logo is almost the same as a seamaster crown of the same period.

Here are the very minor size differences
Speedmaster 321 crown 6.75 x 3.8mm (4.8mm including protruding brass tube)
Seamaster 300 crown 6.75 x 3.3mm

This explains it a bit better

 

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befobe

·Aug 12, 2019

That cannot be clearer, thanks Stuie. Think I'm ready now to search through the net the best crown for my speedy... Of course I would prefer an "old" one...
(3.3 and 3.8 makes a difference that can be easily seen with naked eyes... I must be careful about that measurement...)