No. You *don;t grind the primary bevel*. That's not what I typed. You grind the secondary bevel (15 degrees or so...or any angle desired). That's the secondary bevel there....that's the one to grind. It will NOT change on you, even after grinding every day for the rest of your life, unless the sharpener (person sharpening the knife) changes the angle of the grind.

It isn;t complicated and the math is still the same.

You are correct that no one you know grinds the primary bevel. I agree. But, *everyone* you know grinds the secondary. Micro-bevels? Some do...some don't. The point I was trying to make, Tom, is that the obtuseness or acutness of the edge is not going to change as was inferred in an earlier post. It won't happen.