My new house in Northern Calif. is 3 weeks from completion. I built a dedcated woodworking shop behind the garage. I went to the lumber mill just up the road to enquire about buying oak lumber to prep for flooring.
They sell the raw oak boards at $1.50 per running foot.. But they advised me to look at a scrap piece of milled flooring before I undertake the project. Aside from the tongue and groove jointing on the long edges, the bottom has some critical rebate grooves. These gouges allow the boards to lay flat at alll times. And they prevent cupping from heat and moisture expansion. And every board must be run through an accurate thickness planer.
The only way to mill these dados on the flats is with a shaper. Not only that, the shaper would need a power feeder. The lumber also needs to be planed. Again, you'd need a power feeder there, too. When you hand feed, the feed rate is inconsistent, so the boards won't come out equal thickness,leaving the floor with edges sticking up and breaking off.
So the three steps are: a) tongue and groove on edge b) dados on underside c) perfect thickness
A router might be able to do the tongue & groove. But you need a shaper and planer with power feeds for the rest.
The raw oak lumber sells for about $1.20 a board foot. That's a lot bettter than milled oak flooring at about $5.50 a foot. When we build a second house on the land we have, I'm going to do this. But I am prepared for a massive amount of work to mill the wood. You need the machinery because the first requirement is very hard wood. Unless you want Pine flooring.
Gary Curtis