How to remove notchless watch back?

Factual Questions
1

Recently Mrs. FtG uncovered an old Borel Cocktail watch of hers from c1962. It’s an interesting watch with a kaleidoscope front and a crystal back. Original band. I want to fix the stem and the back needs to come off. But there seems to be no way clear way to do this.

There are no pry notches nor any notches for using a screw-off tool. I’ve tried the soft rubber ball trick to screw off the back but I’m hesitant to apply much pressure given the crystal on the back.

Here’s a video of a similar model. Hers has the black face instead of white, which makes the kaleidescope even more interesting. The one in the first video clearly shows notches for taking off the front and back covers. But, like I said, this one doesn’t have those.

I just want to get it working well enough for showing it once in a while. Don’t want to spend money on taking it to a watch repair shop.

So many Dopers have cool knowledge of various things, I’m hoping one of you can help me out.

2

It’s probably a pressure-fit back. Unless you’re afraid of damaging it or reducing its value, use something sharp and sturdy like a pocket knife blade to gently pry up the edge of the back. Do it like a paint can, little tweaks at different points around the rim. It will rise a little and then pop off.

Putting it back on is simple unless it has a bubble crystal that you can’t put pressure on. A hard flat crystal can take the pressure, on a hard surface covered with a cloth, but a bubble crystal will need a watch anvil that can support the case while the back is pressed on.

Harbor Freight Tools has a cheap anvil/tool set for watch cases.

3

Oh, crap, never mind. You said there was no pry notch.

4

Here is one guy’s solution.

(seeing as the poster’s name in the link is “crotch has teeth,” I better amend that to "one GIRL’s solution.)

5

Thanks for the link. Based on the description it sounds like what’s going on with this one. I knew about that site and did some searches but I guess I didn’t try “mystery dial” (which is the general term for the family of Borel watches with various turning dials).

Not sure about using epoxy on the back. Definitely don’t want to apply it to the back crystal and not sure if I could get a good hold on the rim. (And then how do you clean it off?)

But I think the key thing is that I now believe it is a screw-off rather than pry-off situation.

I wonder what the no-longer-made special wrench looked like.