HI- thanks for the reply. This hadn't anything to do with the pic you sent about a buttonholer It's only an overcaster Style #2, not a #1. It could be for a white but I'm not finding any info online about that in any direction. no, no manual and a search for that leads no where, even on ISMACS where I tried prior to writing here.
The adaptor clamp shown on your buttonholer is like the Overcaster. That is different than the Style #1 as best I can see. I'l try it on my White 77.
Wish I could find a manual or even a PDF for it!
thanks for the help!