With access to a CAD/CAM system and a CNC machine, it's pretty simple.
I doubt that 'access' is the sole variable here. Here's thought:
1. Make models for various Speedy references (and maybe for a 176.007 while you're at it 😉)
2. Produce them on demand
3. Repeat 2 until you can buy yourself a nice 2915 or something.
Do them in nylon/plastic, mine is made from white nylon, impossible to scratch any case back, and surprising how many different backs they fit
You’re right, it would actually work in most cases, but not when the case back is stock as hard as it was on my -69. The teeth would either snap, or they would give a bit and try to leave the case back. That will never happen, if made of aluminum or brass, and since the work is the same, why not use safer materials. And I really can’t see how aluminum or brass should be able to scratch stainless steel…….
I managed to buy an Omega case back tool, part number 508-0009, which is very similar to the tool you have designed and fits the Speedmaster case backs. I just need to make a small crossover to fit it into my case opener.