Thread: One edge is sharper than the other

Originally Posted by holli4pirating

On a microtome and a Japanese razor, there is only one edge.

This is impossible. Please draw a bevel with only one edge.

Mathematical stuff:
Even if one side were curved, at the microscopic level it will approximate a straight line. (definition of a derivative) Whenever two lines intersect an angle is formed. Even if two curves intersect, their intersection is still an angle. In a very extreme case, let us assume one line is horizontal and the other is verticle, forming a ninety degree angle. One only has to rotate it 45 deg and you have a (very wide) bevel.

Originally Posted by khaos

This is impossible. Please draw a bevel with only one edge.

Um... maybe I don't know what "edge" means

How many edges do you count here?

Originally Posted by holli4pirating

Um... maybe I don't know what "edge" means

How many edges do you count here?

So how is that different from a bevel form by the intersection of two faces at different slopes? It still forms an edge/point. Just at a different angle...
if it shaves on one side that means there is an intersection of planes sharp enough to shave and I see no reason why it shouldn't shave from the other side *if you changed your angle of attack*.

Look whatever. I will cede on grounds of experience.

Right. As there is a pretty specific way in which one tends to use a razor, the debate about angle of attack seems moot. I am pretty sure that if it were worked into just the right corner you could produce a razor that would only shave if you scraped it across your face with the blade at 90 degrees to the skin. I get what you are saying about there being a bevel that inevitability must arise from two surfaces meeting, but that doesn't get the OP's face smooth. "Angle of Attack" just sounds like compensating for a jacked up bevel.

My understanding is that a bevel is different from an edge. As I understand it, the bevel is the area on each side of the razor near the edge where the razor touches the hone and you can see hone wear. The edge is the "line" or "curve" (for a smiling blade) where the bevels intersect.

It would be as though I took a shave ready blade and applied a few layers of tape to one side of the spine. Worked the taped side a bit then shaved.

This is what I am getting at with the "angle of attack". On the top you see a single, normal bevel/edge/whatever. Lets say it forms a 150deg angle with your skin (arbitrary, I don't know what angle it is, but for sake of argument).

In the second line one sees that with the weird formation in question, if you tried to shave normally, one way will be fine, while the other will actually yield a crappy angle, say 95deg (once again arbitrary for argument)

In the third line I am showing how if you flattened it out you could restore the 150deg angle.

Originally Posted by blockhead

It would be as though I took a shave ready blade and applied a few layers of tape to one side of the spine. Worked the taped side a bit then shaved.

You are correct. This is all that I was saying. I didn't want to get into the math of it. In my first post I just said technically there is a bevel, just at an angle different to the expected, upright, standard bevel angle. I was just saying that it is impossible for it to only be sharp on one side. Not that it was impossible to not be shave ready on both sides. Clearly that bevel needs work. I am not arguing that. I was defending the math stuff because Holli challenged it.

Here is my OP. Please note in red:

Originally Posted by khaos

Since it is mathematically impossible for one side to be sharp and the other not (not gonna go into this though) what I *think* may have happened is you honed one side more than the other, and so the angle of attack is different.

+1 on hi_bud_gl go back reset the bevel and see what happens.

khaos,

When one side of the razor doesn't make contact with the hone all the way to the edge but the other side does, the razor is left with one polished bevel which is flat all the way to the edge, and one that is not.

The above diagrams show a pretty ridiculous case. It looks like someone is using 10 layers of tape on one side of the spine only.

Now, a dull razor is one that is rounded at the edge, is it not? If however, one bevel is not making hone contact all the way to the edge, that side of the edge is going to be unpolished and remain rounded. The other side may sharpen just fine, but the rounding on the dull side will prevent any angle of attack from being capable of cutting hair with any ease. If I cut an egg in half, you'll see a sharp divide if you look from the side which was cut, but you'll see a gradual roundedness from the other side of the egg, as though it was never cut at all.

The mathematics presented above are fine, but they don't represent the issue at hand (which is one bevel rounding away from the flat bevel at such great angle it is incapable of effectively cutting hairs)

edit: I see your last post. Of course it depends how dull the razor was to begin with and of course how much more good contact one bevel spent on the hone than the other bevel. Gradually, even if one bevel is way off, the other bevel will wear into the roundedness of the opposite side, helping it to sharpen. But that process is destructive and far slower than simply finding the right honing stroke for each side