I assume you’re talking about a Danish frame saw, and not a beast like Ruobo saw. You can find plans here for this type of saw and modify accordingly. https://www.blackburntools.com/new-tools/new-saws-and-related/danish-frame-saw-parts/index.html I think the oak, though maybe a little thin, could work for the uprights. But it’s a heavy wood, and I think you’d be better off with a lighter wood like pine for the stretcher. When I made the Blackburn saw that’s what I used, with ash for the uprights.