A question on hollowness.

[Rick Sparks]

Would somebody please explain the difference between full, half, and quarter hollow ground? Especially how you can tell just be looking at a razor and what difference it should make to honing?

I know a wedge from a hollow ground, and I understand that the hollowness is how the spine acts as a guide for the proper angle for honing, but I don't have a clue about the different degrees of hollowness. It seems like something I ought to know, so I'd sure appreciate someone sharing on this.

Thanks!

 

[Tolduonce]

Good question. I want to know too.

 

[gugi]

those are approximations. how about a real chart:

 

[English]

This photo is quite helpful.

http://www.revisor-solingen.de/html/wissenswertes.html

You need to page down and look below the numbers 1,2,3.

Basically, more metal is ground away and the blade gets lighter and more flexible as you move from a full wedge to a full hollow. If you try different grinds, one of them will be perfection for you.

As a general observation, men with wirey and strong growth hair tend to like blades that are heavier and with a light grind.

 

[English]

As for the effect on honing, the easiest to hone is the full hollow blade, because of the blades hollwness, very little metal touches the hones and so the sharpening process is very quick and efficient. But because the blade is very flexible, it is essential to hone with a very light touch and not distort the geometry of the blade by putting pressure on the blade during the honing process.

The most difficult to hone is the "full wedge". This is because the whole of the metal will touch will theoretically slide along the hone.

In actual fact, there are very few full wedges around and most blades have a partial hollowing meaning only the honing bevel and the edge bevel are touching the hone. Some honers will put tape along the spine on wedgy blades. This lifts the spine off the hone and stops the face of the blade hitting the hone. The more layers of tape, the more the wedge becomes like a full hollow for honing purposes.

Despite the tape, full hollows are easiest and the edge gets progressively more difficult to hone as the blades get stiffer and progress to full wedge. The stiffness of the blade does not tolerate any irregularities either in the perfect alignment of the metal or the perfect flatness of the surface of the hone. Therefore the stiffer or more wedge shaped the blade, the more difficult the blade can be to hone. Once you have been honing a little while and you can feel and sense these things however, it becomes a non issue.

 

[Rick Sparks]

I have to admit that I'm still a little fuzzy on this issue. I get the general idea, but how do you tell by looking at a blade you're holding whether it's a full hollow, or half-hollow grind? Is this just something you get a sense of after looking at lots of blades, or are there specific landmarks to look for?

 

[Jatte]

I like this one

 

[gugi]

I like this one

the problem i have with this is that bellied hollow is redundant, all double ground have a belly so full hollows are that

 

[gugi]

I have to admit that I'm still a little fuzzy on this issue. I get the general idea, but how do you tell by looking at a blade you're holding whether it's a full hollow, or half-hollow grind? Is this just something you get a sense of after looking at lots of blades, or are there specific landmarks to look for?

you look at the profile look at a picture that tells you what's full , 3/4, 1/2, 1/4 etc. and figure out which one it's closer to.
the problem is the picture - everybody draws them any way they like.
to be meaningful there has to be a pretty strict definition, not just a drawing.

 

[English]

I have to admit that I'm still a little fuzzy on this issue. I get the general idea, but how do you tell by looking at a blade you're holding whether it's a full hollow, or half-hollow grind? Is this just something you get a sense of after looking at lots of blades, or are there specific landmarks to look for?

You are joking with us.

Look at the pictures. Now look at your blade. Look at the end straight on.

Have you got it now. If you haven't, nobody can help you.