Hi Paul,
I think the ill-written point of the drawknife section is that while one should have a sorta flat back to drawknife, the bevel side is rounded. Think about the results of Jacob's sharpening technique.
I say sorta flat because while it needs to be even from the back edge to the front edge, it does not need to be flat across its width like a chisel or plane blade. Look for even scratches all the way from the back to front and along the back. That's all that is needed. Could be he is saying that, but I cannot tell.
For the bevel side, Dunbar makes the point that new drawknives come with a flat bevel--and I have seem them hollow ground as well. Either is wrong. Instead, the bevel should be a curve from the top surface down to the edge. It also should not be too long a bevel area...but not too blunt either [unless you are peeling logs, but I suspect most are not using it thatta way].
The way I do it is to make a simple rocking motion as the sharpening tool is going from the top surface to the edge. Just a slight motion.
Most drawknives can be shaped by a file, too. At least vintage ones. The steel is only as hard as an axe, perhaps a little harder. So if I get a chip in the edge, I'll first use a coarse file, followed by a finer file to shape and smooth the edge. Then I will use a stone. For the workshop, and after any shaping, a coarse stone followed by a smooth stone should suffice. Mine are two-sided round stones made for sharpening axes.
Clear as mud?
Take care, Mike
Oops--edit to add that the point of the rounded bevel is because most often the drawknife is used bevel down. Controlling depth of cut is a matter of turning the wrists so the edge rises up out of the cut or dives down into it. The rounded bevel help "turn" the cut up or down.
