Thread: wider bevel=more flex?

I think the sharpness of the actual cutting edge depends on the steel used, the inclusive bevel angles, and how well they meet (i.e. level of polish/grind). The edge, sharpness wise, doesn't care how much mass is behind the bevels.

Flex-wise, the amount of steel behind the edge (full-hollow vs. wedge vs. "singing" grind) has a major effect on flex, but little effect on edge sharpness. The thinner grinds do sharpen up faster (sometimes) because there is less steel to remove.

Basically, I agree with hi_bud_gl. I just like to make it sound more complicated.

I'm not sure about the bevel flexing, but when it comes to the razor flexing, blades with wider bevels tend to flex less. (Wedges have wide bevels because they are thick and they don't flex; full hollows have narrow bevels because there isn't much metal in there, and they flex a lot.)

Originally Posted by holli4pirating

I'm not sure about the bevel flexing, but when it comes to the razor flexing, blades with wider bevels tend to flex less. (Wedges have wide bevels because they are thick and they don't flex; full hollows have narrow bevels because there isn't much metal in there, and they flex a lot.)

Although wedges may have wider bevels, I think the rigidity (i.e. less flex) of the edge is a result of the thicker grind, not because of the wider bevel.

Hollow grinds do have more flex, but this isn't a result of the bevel width so much as the grind of the razor overall.

If a narrow bevel on a hollow ground razor still has more flex than a wedge razor with a wider bevel, then wouldn't a wider bevel on a hollow make this gap in flex even wider? (metaphorically speaking...)

BTW I have no proof for my ideas, I am merely hypothesizing. But I welcome more disagreement, it makes for interesting conversation. I don't mind being wrong!

Two parameters define the width of the bevel.

1. the bevel angle.
If the angle is smaller (due to a reduced spine) the bevel sides will become wider. The smaller the angle, the more flexible the edge, and it will also be a bit weaker.

2. the thickness of the blade.
A full hollow has a very thin blade, hence a small bevel is to be expected. A wedge has a thick blade, hence it will carry wider bevel sides. In this case the wider bevel will be a bit sturdier, because it contains more steel for the same height. (it has a wider base).

If you see wide bevel sides on a full hollow razor, that always means that the spine underwent a lot of honing wear. The steel of a spine can possibly be softer than the edge. As a result the bevel angle of some razors slowly diminishes over the years of honing. At a given point I believe that will start to have an influence on the durability of the edge. It depends on various other factors, such as beard type, when that starts posing a problem.

If the blade is thin enough to flex, so will the entire edge, for it is even thinner.
If the blade is thick enough not to flex, only a the last bit of the edge is free to flex, from the point where it becomes thin enough to do so.

In my opinion, flex helps the edge to follow the landscape of the skin surface better. At the same time those edges might have problems shaving a coarse, or poorly prepped beard. They have a harder time resisting serious cutting stresses.

Bart.

Originally Posted by Bart

Two parameters define the width of the bevel.

1. the bevel angle.
If the angle is smaller (due to a reduced spine) the bevel sides will become wider. The smaller the angle, the more flexible the edge, and it will also be a bit weaker.

2. the thickness of the blade.
A full hollow has a very thin blade, hence a small bevel is to be expected. A wedge has a thick blade, hence it will carry wider bevel sides. In this case the wider bevel will be a bit sturdier, because it contains more steel for the same height. (it has a wider base).

If you see wide bevel sides on a full hollow razor, that always means that the spine underwent a lot of honing wear. The steel of a spine can possibly be softer than the edge. As a result the bevel angle of some razors slowly diminishes over the years of honing. At a given point I believe that will start to have an influence on the durability of the edge. It depends on various other factors, such as beard type, when that starts posing a problem.

If the blade is thin enough to flex, so will the entire edge, for it is even thinner.
If the blade is thick enough not to flex, only a the last bit of the edge is free to flex, from the point where it becomes thin enough to do so.

In my opinion, flex helps the edge to follow the landscape of the skin surface better. At the same time those edges might have problems shaving a coarse, or poorly prepped beard. They have a harder time resisting serious cutting stresses.

Bart.

Nicely put Bart

Here is my rebuttle to the legend of the Wapi being a thick, beefy grind:

That pic was taken using very light pressure of the blade against the edge of my desk. It flexed back immediately from the distortion seen there.



I subsequently re-ground that Wapi, and you can see here, that as a result, the bevels got much wider, and I can tell you that there was no flex remaining as there was in the original blade.

Originally Posted by Seraphim

I subsequently re-ground that Wapi, and you can see here, that as a result, the bevels got much wider, and I can tell you that there was no flex remaining as there was in the original blade.

Interesting....that must be because the new bevel is now in the thicker part of the blade, since it's closer to the spine....

Originally Posted by Seraphim

That pic was taken using very light pressure of the blade against the edge of my desk. It flexed back immediately from the distortion seen there.



I subsequently re-ground that Wapi, and you can see here, that as a result, the bevels got much wider, and I can tell you that there was no flex remaining as there was in the original blade.

I'm very puzzled, are you saying that the Wapienica flexes less after you have ground it thinner?

Originally Posted by Bart

2. the thickness of the blade.
A full hollow has a very thin blade, hence a small bevel is to be expected. A wedge has a thick blade, hence it will carry wider bevel sides. In this case the wider bevel will be a bit sturdier, because it contains more steel for the same height. (it has a wider base).

Not sure if you said that quite right? Assuming that "wider bevel" means that the bevel is "taller" extending further toward the spine from the edge then, at the same height (distance from the edge towards the spine) it would only contain more steel if the bevel angle is wider. The implication being that wedges have thicker spines for the same width blade.