I was reading old threads and I found one where @Archer posted a picture of a SM300 with a display case back. Are these the ones made by Thomas Preik? There is a franken SM300 on ebay with a Speedmaster case back (yes, really), does that mean that Speedmaster case backs can fit on the SM300?
I think Al made the case back made for a customer. I imagine he had a new Omega case back machined to open up the hole and then installed the sapphire, but I am sure he will be along to provide more detail. I have thought about contacting Al to ask him to make me one, I'm sure others would also be interested.
I would I asked him some months ago, but I don't think they will be available again in the foreseeable future. A shame cuz I would really like one
This is not an aftermarket case back, but a genuine Omega SM300 case back that was machined to have a genuine Omega sapphire crystal and gasket installed. The crystal is from a sapphire case back Speedmaster, so this made from all genuine Omega parts. I made a bunch at the time and put them on watches I was servicing for people who wanted one. I had enough interest to get another batch done, and since my watchmakers lathe doesn't have a cross slide, I had a "friend" in Montreal I know do the machining for me. I sent him a number of case backs well over a year ago to get the machining done, and not long after he stopped responding to my emails...I doubt I will ever see those parts again...