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Opening a tetradecagonal caseback

Pascal S
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With my collection of vintage Lemania calibre 30xx/36xx watches continuing to steadily expand, I am thinking that it would be nice to have a dedicated tool to open their respective screwdown caseback.
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All of them seem to rely on the same tetradecagonal design with 14 flat sides and a distance of 31.5 mm between opposite angles.
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Since this appears to be a standard, I imagine that specialized tools once existed for these watches. Unfortunately, my search has so far come up with nothing, to the point that I am now considering having a caseback opening device 3-D printed. But before I embark on this, I wanted to gather some advice from you folks. Any lead would be welcome.
 
Rasputin
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Super glue a socket lug nut, remove caseback with socket wrench, and acetone to remove lug nut. Obviously don’t do this with painted or plated casebacks.
 
Ron_W
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Pascal S Pascal S
That's exactly the kind of tool I had in mind. Most of the ones I've seen have only 10 sides, so I didn't know if other versions existed.
There are 15 sided as well but search for ; vintage caseback tool - wrench - opener, as well as these are listed under various names. And some are offered in lots but mostly dont have the inner size listed, you have to ask the seller. If you find one in 32mm you can maybe adjust it to fit yours ?
 
Pascal S
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I successfully use a ball to open and close 8 out of my 9 watches. It's only one that is currently giving me grief. And I'm fully aware of the nut+superglue trick, even though I would rather avoid it if I can.

My aim is therefore to find out if I can source a dedicated tool, which would make my life easier with all my watches. After posting the same question on a French language forum, someone posted a picture of 3 of these wrenches, at precisely the right format. So now I know they exist. Finding one is another challenge though...
 
redpcar
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I've had good luck with a large crescent wrench. Ground down the curved tips of the wrench flat to maximize the surface contact. I attach to the case back with the wrench perpendicular, not the traditional way of turning a nut.
 
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