Term for multi-size American pocket watch case? And case sleeve sizing?

[mbwatch]

Hi everyone - I have an Elgin 6s watch I'm getting ready to case but need to find a case sleeve (I broke the original). I've never needed to source a sleeve independently before and I'm finding some sold by measurements and others by movement size. I'm guessing measurements (thread diameter, overall length) is the more reliable method here.

But I have a question about the case. This is a coin silver case with no manufacturer's mark I can find; it's just stamped "coin" inside. The case has a large spacer ring inside which makes it seem like it might support more than one size movement. The 6 size movement is 34.68mm in diameter and the spacer ring is about 38.6mm. That places somewhere between 10 size and 12 size according to PWDB's listing .

Is there a name for this kind of case? Would a case like this actually fit a 10 size or 12 size movement without or with a different spacer, or is this probably just a straight 6 size case with a larger diameter? I'm curious about this because the measurements of my broken case sleeve are much larger than any I see listed as 6 size. Those are 3mm thread diameter while mine is 4.2mm. It's more difficult and more expensive than I expected to buy a sleeve alone. No "bag of 20 for $5" as I had hoped.

I have head the term "spread case" and have a couple of those, which hold a small 6s or 0s movement but are wider, flatter cases more like a 12s overall. They don't have a spacer and would for sure only fit the movement they were designed for.

Thanks

[CYCLOPS]

it would help to have the old sleeve to compare, you also need the stem and crown not showing in picture, 6 size cases and movements are plentiful on Ebay, I can't tell if you have an open-face or hunting movement, because that will determIne the correct style of case, I say that because of the chip in the dial around where a setting lever could be for a hunting model and the case shown is open-face....Waltham used a 6/0 movement with a larger spacer in 6 size cases, so it has been done...

[mbwatch]

7 hours ago, CYCLOPS said:

I can't tell if you have an open-face or hunting movement,

Elgin 206 is a hunting movement, this one happens to have a conversion dial with no seconds hand that makes open face, stem at 12.

This is a few weeks old. Last week I did find someone selling a random assortment of 16s and smaller sleeves inexpensively. I needed approx 4.2mm thread and 7mm overall length. My assortment had one that fit and I was able to move forward.