Onto the frame, rive the birch (random piece of metal used as an ad hoc froe). I have since got an actual froe - but this worked surprisingly well. And make the blank with a drawknife and a couple of planes. Mark out the handles. And cut to very rough size. Clean up with rasps, spokeshave and chisel, just need to get to more or less the final profile so I can test & tweak it. Make the crossbar in pretty much the same way. Chop out the mortices in the handles. Test fit And that's about it for the rough frame.
I can see where that would be a plus. I have been using some 4/4 and 8/4 stock milling it down with the bandsaw or table saw, usually run the cut edge through the planner to get a smooth face again, keep the length square.
Ah, I don't have any of those things - a combination of a lack of room and I'd probably accidentally lop my arm off in the first 5 minutes. So it tends to be split the big stuff, saw the small stuff & plane it square.