Jim, I'm glad you linked that video! The reason is that I was getting ready to chime in that I believe that the "D&M #11" must have been a copy of the 1/8 HP version that Gil referenced as being from American Model Supply. I uploaded that video to YouTube a few days ago. Here is the page from their 1986 catalog:
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This is the set of castings that I purchased:
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Here's some pictures of the finished engine:
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I believe that the AMS engines may have also been the inspiration for Anton Bohaboy's 3/4" bore version:
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Paula