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Would an 1863 case back fit the body of the newer 3861 hesalite speedmaster ?

G
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From what I read the 3861 is decorated already hence the absence of a "3863" movement just for the new sapphire sandwich.

In other words, the new hesalite and sapphire sandwich version have the same decorated movement.

Question is, if I want the new hesalite speedmaster, but also want a display caseback, can I just get a used caseback from say a 3572.50 and fit it on the body of the speedmasters?

Bonus question: are the old dials (e.g. mitsukoshi) also compatible with the newer speedmasters?
 
Omegafanman
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Keep in mind the 3861 dial has a printed and not an applied logo.
I wonder if a hesalite crystal would fit on a 3861 Sapphire sandwich that has the applied logo dial. I imagine the dials are interchangeable.
 
G
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Omegafanman Omegafanman
Keep in mind the 3861 dial has a printed and not an applied logo.

The 3861 dial on the hesalite version is printed as well. I believe it's more a matter of internal case and movement geometry.

I wonder if a hesalite crystal would fit on a 3861 Sapphire sandwich that has the applied logo dial.

Historically the hesalite crystal and sapphire crystals were never interchangeable, but not because of the dials, but because of the case.

I've had a Mitsukoshi dial as well before on a hesalite speedmaster, and it did have an applied logo.

So I guess what I'm trying to say is that the applied logo I believe should be less of a concern than everything else in the old parts and the new case.

But then again I know nothing about these new models. Perhaps someone like @Archer (apologies for cold tagging) that has dissected the new watch would be able to chime in?
 
Archer
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Few questions in this thread, so I'll provide what information I can...

The acrylic crystal on the 3861 model (31030425001001) is the same crystal that has been on the previous Speedmasters, all the way back to 1968.

Dial for the 3861 acrylic crystal is 31.2 mm.

Case back seal for this watch is 088NS5090 | SEAL O-RING D34.5 D36.1 Ø0.8

If I look at a previous Speedmaster, say the 35705000 and the 31130423001005, they use the same parts below:

It uses the same acrylic crystal as I noted.

The dial is also 31.2 mm.

The case back seal is 088NS5140 | SEAL O-RING D34.5 D36.5 Ø1

Looking at the sapphire 3861 (31030425001002)...

The crystal is 34.2 mm in diameter, and then there is a crystal gasket on top of that, so the opening in the case is larger than the crystal.

The acrylic crystal is 34.11 mm in diameter.

It would be too small to fit directly into the sapphire case.

The case back seal diameters would suggest that the case backs may be swappable between the older designs and the 3861, but of course one would have to try it to be sure. It appears that the only difference is that the 3861 uses a slightly smaller cross section seal.
 
G
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Archer Archer
Few questions in this thread, so I'll provide what information I can...

Thank you @Archer, appreciate that a lot, definitely helps understanding the differences and compatibility of parts in the new and old versions
 
G
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nicolamilton nicolamilton
According to this:
https://www.spiralwinderwatchparts....exhibition-caseback-for-the-omega-speedmaster
"It is not designed for the 1957 Trilogy Speedmaster, the new 3861 Speedmaster, or any 3861-equipped watch."
I would say no

Was actually thinking about the official display casebacks, but appreciate this nonetheless.

A possible interpretation to that is that they simply did not design their own casebacks with those watches in mind hence are unable to confirm/guarantee proper fit.

PS: love that photo of the blue snoopy
 
nicolamilton
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G grandphuba
Was actually thinking about the official display casebacks, but appreciate this nonetheless.

A possible interpretation to that is that they simply did not design their own casebacks with those watches in mind hence are unable to confirm/guarantee proper fit.

PS: love that photo of the blue snoopy
Well, they tested several others. Maybe you're right, but I think they won't fit.
 
Omegafanman
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Archer Archer
Few questions in this thread, so I'll provide what information I can...

The acrylic crystal on the 3861 model (31030425001001) is the same crystal that has been on the previous Speedmasters, all the way back to 1968.

Dial for the 3861 acrylic crystal is 31.2 mm.

Case back seal for this watch is 088NS5090 | SEAL O-RING D34.5 D36.1 Ø0.8

If I look at a previous Speedmaster, say the 35705000 and the 31130423001005, they use the same parts below:

It uses the same acrylic crystal as I noted.

The dial is also 31.2 mm.

The case back seal is 088NS5140 | SEAL O-RING D34.5 D36.5 Ø1

Looking at the sapphire 3861 (31030425001002)...

The crystal is 34.2 mm in diameter, and then there is a crystal gasket on top of that, so the opening in the case is larger than the crystal.

The acrylic crystal is 34.11 mm in diameter.

It would be too small to fit directly into the sapphire case.

The case back seal diameters would suggest that the case backs may be swappable between the older designs and the 3861, but of course one would have to try it to be sure. It appears that the only difference is that the 3861 uses a slightly smaller cross section seal.

Many thanks for the detailed reply.... you could see our direction of travel but it looks like the door is bolted.
 
Lex_Lugga
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Maybe I’m missing something here, but why not just put a 3861 sapphire model caseback on it?
 
G
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Lex_Lugga Lex_Lugga
Maybe I’m missing something here, but why not just put a 3861 sapphire model caseback on it?

1. I think it already goes without saying that they fit hence me not bothering me to include that option in the question.(it would be more surprising if they didn't given they used the same movement already). But yes, that is an option if it is possible to acquire such a part.
2. But most importantly, 3861 models are new I doubt I can find extra parts from that model online, let alone in my country.
Edited:
 
G
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@Archer I know you said the dials have the same diameters for the older and newer versions, but would have any insight in terms of dial compatibility as well? Would the movement, stems, mounting points, be the same? i.e. can I fit a mitsukoshi dial on the 3861 versions?
 
Archer
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G grandphuba
@Archer I know you said the dials have the same diameters for the older and newer versions, but would have any insight in terms of dial compatibility as well? Would the movement, stems, mounting points, be the same? i.e. can I fit a mitsukoshi dial on the 3861 versions?

No idea - would have to physically try it to find out.
 
Lex_Lugga
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G grandphuba
1. I think it already goes without saying that they fit hence me not bothering me to include that option in the question.(it would be more surprising if they didn't given they used the same movement already). But yes, that is an option if it is possible to acquire such a part.
2. But most importantly, 3861 models are new I doubt I can find extra parts from that model online, let alone in my country.

Makes sense. Did not realize parts are hard to come by where you are. I recall to do the swap on the 1861 it also required the spacer from the 1863 in addition to the caseback. Not sure if that’s the case for the 3861 but something to keep in mind.
 
amfalconer
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I think the spacer was only there to take up the slack from the 1861's anti-magnetic cover, which was not there on the 1863.

As the 3861 is anti-magnetic as per the rest of Omega's master chronometers, then, I'd guess there's no requirement for anti-mag.measures on the closed caseback versions.
 
KLXN
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Archer Archer
No idea - would have to physically try it to find out.
Sorry for reviving the old thread, but I'm curious if somebody has already tried swapping the dials between 1861 and 3861?
 
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