I know that for the 1861 series you just need to swap for the higher display version, but for the 321 as far as I know it's just an addon work but I did see one person reporting that you can use the old taller spacer ring used for the cal 863 for the 321. That was just only one data point so I didn't really trust it, but perhaps that's what your watchmaker is talking about. Who knows maybe he's just trolling us .

 

Here is the FOIS with sapphire caseback

The caseback tool I use - made by tog_man, gives a very nice fit with minimal chance of slipping or damage


The parts side by side. The gasket is the one that goes on top of the movement spacer


The movement spacers


And finally the case back installed on FOIS


Some points to note if doing this yourself. I use a case back opener from tog_man (ebay seller), I find these work really well and are very straight forward to use. I use finger cots to ensure that my fingers dont touch any of the movement, anti-magnetic cover etc.
When I put back the FOIS case back, it screwed down completely without any major resistance from the o-ring, so I went ahead and replaced the o-ring. It would be advisable to replace the case back o-ring as a matter of course, and also a small amount of silicone grease on the gasket.

 

Nice work! Have you compared this togman case opener to the one made by our very own @Pahawi ? Interested in the differences.

 

Yes I have both and their action is pretty similar. The togman one has round brass type pins and Pahawi's the pins are long blocks which fit nicely into the Speedmaster case back. Pahawi's has slightly more of the pin touching the case and the part which would push against the case is flat so that would be the main benefit.
The reason I use togman's is because it also fits a number of other non Omega cases and I have a few of his openers for various other cases. I have a handle which fits in the top and makes case back opening / closing very simple action which I've become used to.

 

I agree the OEM looks better but it wasn't worth the hassle or cost to me personally for mine. The Thomas one was less than $100 and a local watchmaker fit it on in less than 10 minutes with no modification or effort beyond removing the caseback and swapping it. Nobody can even see the back anyway other than yourself and the watch looks the same from the side.

 

Thank you for the comparison! I already picked up the Pahawi one, but I think I will have to pick up the togman as well as a good sturdy backup.

 

True from the time and money point of view. But most times, it is what i can see/know when the watch is off my wrist with me looking at the movement that bothers me. The overall flow of the OEM still has my vote.

 

Nice! Is it waterproof with the hesalite on it? Who did the relume?

 

Thanks for sharing! Your test put to rest the uncertainty on whether the case-backs of the regular speedy pro and the FOIS / CK2998 were interchangeable

 

yes, it is waterproof and I did the relume

 

I was asked recently about the Preik case back and if it fitted the FOIS. Since my FOIS uses the same size case back as the normal Speedmaster, then logically a Preik case back for the normal Speedmaster should also fit.




As far as I know this is a standard Preik case back for the normal Speedmaster. The case back has a thread of approximately 33.7mm and the spacer is 31mm x 3.04mm

Once the case back is tight it fits up snug to the case. Everything looks and feels tight, although when gently shaking the watch there could be the slightest sound, hard to say to be honest though. But this was just to show that the Preik case back does fit the FOIS, but the original FOIS is going back on anyway as I have another use for the Preik caseback.

 

Which model speedmaster pro Sapphire caseback was used in thks mod?

 

What do you think of these?
https://www.spiralwinderwatchparts.com/product-page/custom-speedmaster-caseback-blank

 

Not too bad..... the anti reflective coating gives a very clear view of the movement

Mine had a very minuscule fleck of dust between the crystal and seal, but I removed the crystal, removed the dust and reseated the crystal.

After fitting the caseback, I then pressure tested the case to 3 bar and no problem with any leaks

 

Looks really good, thank you. The only problem may be missing anti magenetic protection.

 

I've not encountered any issues with magnetism on my Speedmasters with Sapphire casebacks during normal everyday use, so I'm not sure how much difference the original metal cover and caseback make. This particular Speedmaster is my everyday work watch so it does get used in a variety of different situations.

 

Those are beautiful pix, especially the additional dimensionality of the movement. Increasingly tempted to go that route. Is there any meaningful difference in thickness with the addition of the sapphire caseback?

 

May I ask why you don't have rodium/ plated finishing in all your 1861 movement? (like other pictures above).
Edit, didn't realize it isn't a FOIS.

 

Spiralwinder delivers sapphire casebacks with proper spacers for hassle-free mounting at the back of FOIS. Here's mine (with custom laser engraving).

 

I like how your watch turned out. I dont like the original caseback as it leaves an imprint on my arm and is not so comfortable for me. It seems your caseback would be a good solution. Have you had your watch pressure tested?