I think I remember reading that for some reason or another (thread pitch?) aftermarket case backs won't work on the Tokyo Speedmasters.
I've taken one apart before to remove a piece of lint on the dial, and though I haven't tried swapping casebacks, I believe a standard 1863 exhibition caseback might fit. Again, I haven't actually tried fitting one so don't quote me on it as I could be completely wrong. The case structure inside is set up like the 1863 because unlike all the 1861 Speedmasters I've opened, it didn't have the iron antimagnetic dust cover pushing against the solid caseback from the factory. And I remember it having 2 gaskets like the 1863 versions (1861 only has one main gasket).
D dlovasicThanks for the reply! Nice Rising Sun btw😉
The reason for my question is because I’m interested in a Tokyo Panda and I would like to modify it a bit for daily wear. Exhibition caseback, 3861 Nixon or Flat Link Bracelet etc.
Anyone else know if the 1863 sapphire caseback would work?
Mr. Archer? I promise not to talk about wrist sores from the Olympic caseback lol!!!!
Any help would be greatly appreciated…..
D dlovasicI just spoke to a gentleman from instagram (@itsabouttime_pieces) and he confirmed that the 1863 sapphire caseback will indeed fit the Tokyo 2020 models.
D dlovasicSo I was lurking around on eBay just now to see if there were any 1863 casebacks available. I did not find anything OEM however I did find someone that sold aftermarket versions. This is what his listing said:
“Will This Fit My Watch?
This caseback fits the following references:
CK2915 / CK2998
105.002 / 105.003
105.012 / 145.012 / 145.0012
145.022 / 145.0022
3750.50/3570.50.00
311.30.42.30.01.006 / 311.30.42.30.01.005
311.33.42.30.01.001 / 311.33.42.30.01.002
It will also fit a plethora of modern models, such as the 1861 Professional (3570.50, etc), ck2998, and FOIS versions. It is not designed for the 1957 Trilogy Speedmaster, the new 3861 Speedmaster, or any 3861-equipped watch.
Dec 2022 - We have been informed that the later runs of ck2998 models (Hodinkee H10, Black Pulsometre) utilize different threading compared to the mainline pre-3861 Speedmasters, as do the Tokyo 2020 Speedmasters. These watches will not be compatible with this caseback.”
So, if this WILL fit all of these models BUT WILL NOT fit the Tokyo models, theoretically, the 1863 should not either. Omega must have used different threading for these SE casebacks to avoid any potential frankenwatches….♂️
Sorry if my previous post was misinformation. I’ll try to clarify this with the gentleman on instagram. If anyone else knows anything, please help! Thanks again!
No, that actually makes sense and reinforces the possibility of an 1863 caseback fitting because 1861 casebacks don't fit on the 1863. All those listed models are solid caseback watches with hesalite crystals, and it would make sense the aftermarket Spiralwinder casebacks are only designed for watches that have a solid caseback.
I don't think Omega made different threading just for the Tokyo 2020. They used the 1863 Speedmaster as a base because they wanted a sapphire front crystal setup (you can't retrofit a hesalite crystal due to the case) but used a solid custom caseback molding based on the 1863 threading.
The 1863 sapphire caseback *should* fit, but again I haven't tried and can't actually confirm so I would defer to your answer from @itsabouttime_pieces on IG.
The 1861 looks as good as the 1863 just without the fancy striping on some of the parts and there's this one little piece of white plastic instead of metal. Here's an actual picture of an 1861 movement with a 1863 caseback conversion:
D dlovasicThanks again for the reply Sir! You are a gentleman! I will definitely confirm the details again with @itsabouttime_pieces on Instagram. He was very helpful with all of my questions as well. He had the exact Panda / Flat Link combo that I am hoping to achieve but he never bothered to change the caseback. Having said this, he did say that it was possible as he knew others that have done the same.
The movement looks great in your photo. I think it will be a bit more interesting than the “Tokyo 2020” solid caseback design.
With regards to the bracelet situation, I have read that the 3861 will fit this case with no issues but I am not a fan of the striped clasp design which happens to be 15mm. If I am not mistaken, the new 57 bracelet has a 15mm clasp with micro adjustment as well. Do you think these are interchangeable?
Clasp won't be interchangeable from the '57 because of the way it connects to the center link. For a flat link bracelet, your best bet is to go aftermarket with Forstner or Uncle Seiko.
I have a 3575.20 which has the 1866 moon/date function, but it has the upgraded finish just like the 1863. This watch has a sapphire crystal and originally came with a solid back, but it accepted an 1863 clear caseback with no issues. So the 2020 Tokyo's should theoretically be compatible. Do you have a source to get an Omega 1863 sapphire caseback?
Personally I like the striped motif on the 3861 bracelets, it adds some texture to the watch.
