Thread: One edge is sharper than the other

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.

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

Originally Posted by hoglahoo

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.

Sorry about that I am still working on how to accurately show .9deg of offset in MS Paint.

Originally Posted by hoglahoo

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.

What about pasted strops which produce two curved, intersecting surfaces?
And calc 101 should explain that at the microscopic level curves are basically flat. HOW curved will determine the angle of intersection. Shall I paint some more?

And for the last time, because I wasn't even arguing with you guys from the beginning, I EXPRESSELY didn't want to go into the math:

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.

I long ago dismissed it as theory and I have been in agreement with everyone all along- the bevel needs to be reset correctly.

Originally Posted by khaos

at the microscopic level curves are basically flat.

Well sure they are. But have you ever tried to shave with a 90 degree-angled bevel when only one side is polished?

angle of attack won't help if one side is as significantly rounded as a dull razor. In fact if you want to make a simplistic theoretical microscopic analysis, won't the resulting angle at the edge be somewhere around 7.5 degrees + 90 degrees? because that rounded side will look like a tangent to the longitudinal cross-section midline of the razor. I'm not so sure there is a good way to cut whiskers with a 98 degree bevel

I'd point you to the threads where bevel angles greater than 20 degrees are mocked, spat on, and beaten to death for their ineffectivenesses, but I happen to know you've seen those too

It seems my observations about the kasumi not being good enough were a little premature. After talking with a couple of people on the site i think that the problem might have been me. I was putting too much pressure on the razor and using a finger on the spine to steady.

I have now taken my finger off and the only pressure applied is the weight of the razor. It is now very sharp on both sides. Looking at getting some CrO and doing some stropping.

Did i see somewhere that instead of a cloth strop you can use nylon webbing?

I'm glad you're getting somewhere with the razor, and I apologize for helping take your thread off course

finding the right stroke for each side of the razor will solve lots of problems

I figure the more debate and opinions i see the more i learn, so for me it hasnt gone off course

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.