zero grind edge bevel

[siguy]

i was just wondering what a zero grind edge bevel is, and what is good about it. my best guess is where the blade just goes straight into the edge like a chisel, but that doesn't make sense because that will dull really quicky after some sharpenings.

please pardon my ignorance but i am relatively knew to the knife world, and i am trying to learn

 

[STR]

Degree in knife bevels is by definition the measurement of the plane angle. Meaning on the plane of the edge you have an arc and the angle is represented by the numbers from 1 to 360 of the arc.

You see so called zero degree edges on knives from Finland, Sweden, the Netherlands and Norway quite a bit. These are more convexed looking than a conventional beveled edge like we see most of the time here in the folders and fixed blade we buy and sell on this side of the ocean. See link to the pic of the three knives in the first diagram and look at the one to the far right. This is not a true zero degree edge but it is so close I thought it was enough to show what I mean. If you take that arc and make it flat from the spine of the blade all the way to the cutting edge with no variance at all that would be a true zero degree edge. Some refer to a zero degree and convex as the same but technically it isn't quite accurate based on my understanding of it. A true zero degree edge would have no variance or arc in the plane.

http://home.nycap.rr.com/sosak/convex.htm

STR

 

[Cliff Stamp]

i was just wondering what a zero grind edge bevel is...

It generally means there is only one bevel on the knife. Most knives have a bevel which shapes most of the knife and another which shapes the edge. The advantage of having one bevel is that it is cheaper to make, they have serious drawbacks from a performance perspective.

-Cliff

 

[HoB]

It generally means there is only one bevel on the knife. Most knives have a bevel which shapes most of the knife and another which shapes the edge. The advantage of having one bevel is that it is cheaper to make, they have serious drawbacks from a performance perspective.

-Cliff

That's how I use the term as well although I would allow a small microbevel on the edge. I would say the performance depends. For a slicer I would say a zero edge at ca. 6 deg plus a microbevel at 12 (included) makes for a much better slicer than 6 deg blade bevel down to 0.03" behind the edge and the an edge bevel of 20 deg. per side. And there are quite a few knifes that come like this factory wise. So performance I would say is a matter of what the numbers are. In general though, two bevels will allow you to adjust better for your needs (more parameters to adjust). Often though it is much easier to put an edgebevel on a zero edge knife than grinding off the shoulder of an edgebevel that is too steep.

 

[Cliff Stamp]

In general though, two bevels will allow you to adjust better for your needs (more parameters to adjust).

Yes, simply consider the fact that there in no way that the primary edge bevel needs to be as obtuse as the edge bevel which directly states a single bevel approach is inefficient. The only time this is optimal is on non-binding media and even then you still have concerns about sharpening.

Often though it is much easier to put an edgebevel on a zero edge knife than grinding off the shoulder of an edgebevel that is too steep.

Assuming the zero-edge angle doesn't need to be reground itself.

-Cliff

 

[MORIMOTOM]

siguy, did any of this help? i have no idea what they are talking about. still dont know what a zero edge bevel is either.

 

[SIFU1A]

a little simpler way to describe is that a ZBG blade has only 2 angles vs a chisel grinds(say a std EKI CQC7 tanto) 3 angles on the edge, a lot of emerson customs are ZBG, my emerson '8 is ZBG and quite sharp, as long as ya dont mind scuffing the back of the blade they are simple to sharpen.

i doubt emerson does them that way because they are cheap to make lol, might be true with moras/etc .

as the '8 w/a ZBG is strictly a SD knife (and a damned sharp one) i see no real drawbacks to it, i dont know how great they would be for edc (i dont think they would hold an edge too well in that role since the edge is so thin) but for what they are designed for ie self defense, i think they rock.

they are a lot sharper than a std chisel grind, a lot sharper than ya can get a std CG imho.

so, like i say, look at a std CQC7 and imagine if it didnt have but 2 bevels vs the 3 bevels on the edge and ya got it.

 

[dennis75]

with this ZBG-term, are you guys simply referring to the full flat V-grind, like a perfect V-shape?

i customized two spyderco's to a full flat grind V, and wow, never had a sharper knife than like that, really impressive

easy to resharpen too, just lay the knife completely flat on the stone and you're done as far as the angle goes.

the edge problably does have some limitations in practical use though, but i think experts like Cliff can explain that better........although i didn't understand a word of his text above, it's like science or something

 

[STR]

Actually it is a full flat grind but there is not traditional bevel at the edge. The primary grind is both the primary grind and the edge bevel because its ground all the way down to the edge from the full thickness to the cutting part of the steel. You typically don't see that with flat grinds at least not any I have seen. Even the ones that are sold as zero degree have what appears to be a 'micro bevel' at the edge which means that they are not quite zero but close depending on how much there is there that is seen.

As Cliff pointed out there are drawbacks to it. Personally I think it weakens the edge, and is better off with a bevel. Most of the ones I've ever bought that were true zero grinds were very soon afterwards taken to my stone and fixed to my liking lets put it that way.

STR

 

[SIFU1A]

yep emersons ZBGs do have a very slight bevel at the edge, but its a VERY slight one.

i wouldnt want a ZBG for anything but a SD knife, oh ya could use them for edc (& i know folks who do) but edc isnt what they are about imho.

 

[SIFU1A]

with this ZBG-term, are you guys simply referring to the full flat V-grind, like a perfect V-shape?

i customized two spyderco's to a full flat grind V, and wow, never had a sharper knife than like that, really impressive

easy to resharpen too, just lay the knife completely flat on the stone and you're done as far as the angle goes.

the edge problably does have some limitations in practical use though, but i think experts like Cliff can explain that better........although i didn't understand a word of his text above, it's like science or something

thats about right, of course emersons isnt ground on a "V" more like I/ that ,kinda anyway lol.

 

[Blop]

i customized two spyderco's to a full flat grind V, and wow, never had a sharper knife than like that, really impressive

the edge problably does have some limitations in practical use though, but i think experts like Cliff can explain that better........although i didn't understand a word of his text above, it's like science or something

Thin, i guess the edge is so thin. Maybe it is that?

 

[Cliff Stamp]

i wouldnt want a ZBG for anything but a SD knife, oh ya could use them for edc (& i know folks who do) but edc isnt what they are about imho.

There are many EDC knives which have zero bevel grinds, most scandinavian blades for example, machetes, and the most common utility knives used by tradesmen, the stanley and olfa knives.


-Cliff

 

[dennis75]

Thin, i guess the edge is so thin. Maybe it is that?

yep it IS thin. but, it is also strong, because basically it has NO edge. it's a perfect V from spine to 'edge', like a japanese katana so to speak.

i use them regularly for opening envelopes and they basically never need sharpening. if they do, like once every 6 months, it takes only 2 minutes to restore it to how it was. i kind of like it

 

[dennis75]

There are many EDC knives which have zero bevel grinds, most scandinavian blades for example, machetes, and the most common utility knives used by tradesmen, the stanley and olfa knives.


-Cliff

you can't be serious?! machetes and stanleys (i assume you refer to "X-Akto" blades/boxcutter-blades) definitely have edges, thus they have one bevel grind. at very low angles, like 5 degrees maybe, but edges they have.

about this subject: when reffering to zero/no bevel, i assume you mean a blade shaped exactly like a V, one straight line from top to bottom, right?

 

[Cliff Stamp]

... definitely have edges

Yes, the defination, as STR noted, is to describe a knife where the edge bevel is zero degrees above the primary grind, i.e., there is no distinct secondary or edge bevel. If it didn't have an edge then it would not be a knife.


-Cliff

 

[Thomas Linton]

Based on lessons from the Land of the Zero bevel (The UK "bushcraft" gang):

A zero bevel knife MAY have a single grind from the spine to the edge. Or, more typically, the "single bevel" starts at some line between the spine and the edge.

The point is that there is no "final" or "secondary" bevel in the last little bit before the ultimate edge. Do a Google search for "Mora" + 'Knife" of "Knives." You'll see the second, typical form of the "zero bevel."

Given that definition, and after checking my observations with knife-makers in Finland, Sweden, and Norway, a true "zero bevel" knife is the exception, not the rule in production knives from those countries. I have several dozen knives from those countries, and only the inexpensive "MORA's" (made by a couple of companies) and two customs (by "Trond") came with true "zero edges." All the rest came new with either a secondary bevel or were convexed in whole or at the edge.

 

[Cliff Stamp]

have several dozen knives from those countries, and only the inexpensive "MORA's" (made by a couple of companies) and two customs (by "Trond") came with true "zero edges." All the rest came new with either a secondary bevel or were convexed in whole or at the edge.

Do the ones with secondary edge bevels have more acute primary grinds. Or are they now just essentially low sabre flat blades?

-Cliff

 

[Thomas Linton]

Do the ones with secondary edge bevels have more acute primary grinds. Or are they now just essentially low sabre flat blades?

-Cliff

Cliff, they gun the gamut - high saber, low saber, flat, diamond cross-section, full convex, flat/convex. What they are not is "zero bevel" - other than the exceptions that I noted. The Helle's come close, but they have a secondary bevel one can see with the unaided eye.

 

[Cliff Stamp]

Are their relatively inexpensive versions with high flat/convex grinds?

-Cliff