I really like my FOIS, but two things really bugged me: the flat-ish crown made winding a less-than pleasurable experience; and the ridge on the case back was digging into my wrist. Others have noted the same thing.

So...I tweaked: put on a replacement case back...and retro-fitted a modern Speedy crown. You can see the results below - uber comfortable to wear on the wrist now, and a fun to wind. Now, if I can just get around to replacing that minutes hand that nobody can see...

Disclaimer: annoying rotated photos. Apologies.

 

I wish all my watches had casebacks like this. I find that Speedmaster and POs with the Hippocampus relief rub my wrist after a few days.

 

Looks good I like the caseback mod, are those still available? ... and can see clearly all hands!

 

Was also thinking of replacing the case back in order to get more space for an engraving. Where's a good place to get one?

 

I think the fellows in Australia (WatchCo) have them; they can be found on eBay.

 

*Breaking out the popcorn, eargerly awaiting answer*

 

And of course, the answer precedes my post! LOL! Thanks M'Bob!

 

I much prefer it with the service case back you've put on. The standard FOIS caseback is too cartoonish for me.

 

but no one sees it while on your wrist

 

May I ask, is this case back thinner than the original? If so, I want in!!! Thanks!

 

For mine, I am considering a CK2998 crown and a regular small seconds white baton...

 

I believe that it does, in fact, have a slightly lower profile. But I can't swear to it, because I so disliked the original case back, that I sort of stashed it away, without keeping track.

I have not tired of the modifications I made, and wear this watch often.

 

That's awesome! Thanks a bunch. (pm'ed for your rec on sourcing one of these replacement case backs)

 

I’d love to replace the bubble back glass display back on my 44mm co-axial Speedmaster. I have yet to find one though.

 

Today’s hot rods are tomorrow’s Frankenstein’s.



Great looking piece, love what you did.

 

Now, if you could just replace the funny logo on the dial with a proper-style AML