Originally Posted by
Brontosaurus
Again, we're moving away from the scale question into the realm of honing technique. But as I was quoted as moving into such a realm, I'll try to oblige.
For starters, we're dealing with a 400 JIS stone as linked, which is fairly aggressive, be it used for chip removal, reshaping the bevel, or (gulp) even reshaping the shoulder of a razor. The knife's spine or shoulder as linked in the video is always raised, while the edge is oriented on the diagonal as shown there. So in honing like this, there is no wear to the knife's spine or shoulder. Enter the straight razor: a modern 5/8 Solingen full-hollow whereby the shoulder/spine and blade's edge are largely running in parallel as ground, and following this, ideally in equal contact with the stone/hone when honing. By orienting the razor's blade on the diagonal as shown on the video for a heel-forward pass as termed, wear to the shoulder/spine would be introduced closer to the head of the razor relative to the pivot point or the heel. Consequently, the same diagonal relationship will need to be maintained in subsequent honing sessions, further wearing the shoulder/spine there relative to the leftover shoulder/spine opposite to the heel as originally ground. Subsequently, if one wants to change the orientation to hone the blade with an orientation perpendicular to the stone, to say nothing of an opposing orientation to creating a push-cutting effect (not that I am recommending the latter), one will then have to chow through a lot of leftover steel in that previously unaddressed shoulder/spine area, leading to a glitch in the bevel at the heel opposite.
In short, by keeping the straight-razor blade orientation perpendicular to the hone/stone's length when honing, one seeks to respect the razor's spine/edge relationship as ground and maintain it as such.