Quote Originally Posted by gugi View Post
Math time: the intersection of two planes is a straight line.

That means that no razor with a smile can have the whole edge on the hone at a single moment. The bigger the smile the bigger the rocking.
I am sorry but that statement is wrong. You are seeing the blade as a single plane.

A curve is made of interjections of lines at different angles. The same applies when talking to planes. A curved plane is made from interjections of straight planes at different angles.

Now, if I can make the edge fully centered in relation to the spine thickness, there will be a point where the edge and the spine share the same plane, and that plane is where the whole edge makes contact.

I can't explain better as English is not my native language, but I hope you get my idea! That if 2 straight lines (edge and spine) can have contact on a hone (flat surface), a curved line (if properly done) can too, as the curve is just a sum of straight lines.