Chisel Grinds

tatsu

tatsu

Basic Member
Joined
Oct 2, 1999
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2,158
Are there any true advantages to chisel grinds besides ease of re-sharpening, and less work when making the blade? Also, I have noticed that most production chisel ground knives are designed for lefties. Why is this?

Thank You.
 
Tatsu,

Traditionally chisel grinds were used for japanese swords and kitchen knives. It was done for it strenght. Also they would also be ground on one side so it would be a strong edge. Kitchen knives that utilizes this type of grind can achieve perfect slicing of fish and meat. Which is why most sushi knives use this type of grind. I think?
To me it is not easier to sharpen maybe for some. Now most companies in the US make chisel grinds on the wrong side of the blade because it looks good in pictures. That is the only reason. I have a BM Emerson CQC7 and it wierd cutting away from me with this knife. BM also produces the Stryker but with the chisel grind on the right side so it fits the right hand user more. Hope this helps.

Liong

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There used to be a very heated debate about this, probably prompted by the trendy popularity of the grind in many "tactical" knives like Benchmade's Emersons. The most critical and funniest commentary might have been Lynn's [Cold Steel] which might be available on his website still.
The topic has been discussed here at some length; sorry, I don't have the thread or link handy. Some of the sharpest knives I own are "chisel grind" and for some tasks, like opening packages, and possibly some woodcraft and field jobs they are fabulous, provided the side you prefer is sharpened. There are people far more expert than I who have advocated the grind, but I think many of them now prefer some variation or assymetrical grinds. Check out Dr. Ron's [Ron Hood] posts or his site in this connection.
I can't say how effective the grind is at penetrating armour in real life [as opposed to drills and practice], I promised my sensei that I would stop hanging out with the samurai and it's been centuries since the last really good armoured battle. Nonetheless, I don't think it is fair to accuse makers like Emerson of using the grind because it is easier or cheaper than other grinds; I'm sure the better makers believe they're more effective for penetration etc. Elishewitz has a very interesting combination that is said to make a wound that tends not to heal.
Other makers, like Britton, say the chisel grind isn't effective for combat.
Personally, I prefer that both sides be ground, and chisel isn't my favourite.
 
I've heard tell the reason that they are ground on the `wrong side' is for the sake of where they put their name when held in the right hand. Can't say that for sure but it's something I've come across.
As for easier to make? well to keep the edge straight when done and to make it with no secondary bevel, meaning the grind goes straight to the edge, is not an easy task to do well, the Emerson from BM has a secondary bevel and I had to resharpen it for my taste.
I've made a couple of knives using the Chisel edge and must say they are extremely sharp knives, with the back side flat or hollowed a little as some do, they shear when they cut with no resistance on the back side. I made mine with a right hand person in mind and they cut very well!
I recently traded my large Tanto that's on my web page, don't know if I'll tackle making another, but from what some Tacticle folks say the chisel edge is awesome for fighting.

G2

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"There are no dangerous weapons;
there are only dangerous men."
.......... Robert A. Heinlein, 1959


G2 Leatherworks
 
Another theory behind the chisel grind is the reduction in friction during a cut. A true chisel grind, one that tapers to the egde with no secondary bevel, has a very low coefficient of friction due to the fact that there is only one cutting angle. You have the grind, and the flat of the blade meeting at the edge. If you are to add secondary bevels, you add another angle and another point of friction. A v or double ground blade would have these points of friction on both sides of the blade where the grind meets the side of the blade, even if no secondary bevel is added. If the knife is truly zero ground, (no secondary bevel)such as RJ Martin's knives (and mine now, too) the edges will be scarey sharp,and strong.

As far as the right vs. left hand debate, I too believe that this is more of an aesthetic dabate. Pepporoni slicing will bring out the differences, as a right side grind allows the slice to be peeled away and the flat of the blade to stay against the meat, allowing for paper thin slices to be made by the right handed users. I chisel grind, and etch my name, on the "passenger" (right) side of my knives for righties, and for lefties on the left side, as viewed from the spine.

To add to the other posts on the strength of the grind, if you are to measure a few thousandths of an inch from the edge of a chisel ground blade with the proper grind angle, it is fairly thick, where a double ground blade will tend to be thin.

Keep in mind that my comments on chisel grinds are based on flat-grinding techniques, and not hollow-ground chisel. which Tim Wright has called "sacrilege!")

Guess I be a fan of the chisel, huh?



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Chris Hatin
hatintec@dellnet.com

www.geocities.com/chrishatin/hatintec.html
 
Chisel grinds are NOT a traditional Japanese sword or knife grind. Phil Hartsfield has been doing some pretty good chisel-ground Katanas and Tantos and others have copied this but that's a modern US interpretation.

Any chisel-ground piece will do a heavy cut that "curves"...the cut will angle towards the "fully flat" side of the blade.

The upside to the chisel is that for a given set of dimensions, you'll have "more metal" in place than any other grind. If you start with 1/4" stock and do a fixed blade in the 6" or more range, you'll have a REAL "sharpened prybar" on your hands. Emerson used the chisel on 4" class folders and I can see some merit to this: in that size and type of knife, blade "toughness" can become an issue and it's too small to worry about "heft and balance" issues. So he ended up with something tough enough to be rammed right through a rib bone or sternum with less risk of blade snapping than you'd otherwise get...assuming the lock holds, of course.

On a bigger piece, especially a fixed-blade with some reach to it, you can do better balance with either a full flat grind as used by Mad Dog, Bagwell and Ernie Mayer or a complex distally-tapered saber grind as used by classic Japanese smiths and a few others.

Jim
 
I agree that chisel grinds are somewhat underated. They are strong and sharp. What more could you want?

Of course, the problem with chisel grinds is that they're asymmetrical, and will therefore cut asymmetrically. When you're cutting down through some material, the blade will pull toward you or away from you, depending on which side is ground.

This is one reason why manufacterers grind their knives the "wrong" way. If a knife is chisel ground the "right" way (ground on right side for right-handed people), then the blade will pull towards you as you cut down. This scares some users. For instance; if you're cutting down through a loaf of bread, the knife will gradually slide in towards your fingers.

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Cerulean

What the hammer? what the chain?
In what furnace was thy brain? - Blake
 
I was doing some chopping on bone using a chisel-ground blade and noticed that the edge strongley tended to roll over to the 'flat' side of the blade. The assymetry of edge leaves the flat side weaker than the beveled side. It is pretty obvious once you see it happening.
 
I was going to give my 2 cents but, I could not have put it any better than most of you have.

I am all for chisel ground blades because they cut so well and are easy to sharpen. I am not a big proponent on using them as prybars but that is just me.

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If a man can keep alert and imaginative, an error is a possibility, a chance at something new; to him, wandering and wondering are a part of the same process. He is most mistaken, most in error, whenever he quits exploring.

William Least Heat Moon
 
Understand, I'm using the term "prybar" mostly to illustrate the "type of strength" they tend to have. In a 1/4" stock FB it's probably overkill, in a modest size folder the strength increase is perhaps worthwhile.

At least in my opinion, the "theoretical ultimate" is the SABER grind found on real Katanas, Khukuris, etc.

Jim
 
Point taken, Jim.
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If a man can keep alert and imaginative, an error is a possibility, a chance at something new; to him, wandering and wondering are a part of the same process. He is most mistaken, most in error, whenever he quits exploring.

William Least Heat Moon
 
My observation and experience with the chisel grind is that it increases lateral strength of the blade but decreases overall cutting performance and makes sharpening more difficult.

The increase in lateral strength is easy to understand because the cross section of the blade can be kept thicker than in any other type of grind.

Cutting performance for general applications is inferior when compared to symmetrical grinds. Let’s look at the traditional examples for what those type of blades where used. As Jim correctly stated, almost all of the Katanas and Tantos had a nice saber grind. Made in the traditional way they had a softer core of low carbon steel, two medium carbon sides and a high carbon edge. A chisel grind would not be possible or useful on this type of construction.

Where the one sided grind was and still is used is on kitchen knives. Mainly the sushi blades are made this way. The idea is to hold the knife vertical while slicing. The flat left side has back support on the material you hold with your left hand, and the ground side will push the material you want to cut off to the right. Why is this important for fish? Because fish (like meat) is sticky. The steep angle will put the piece you are cutting off to the right where it will easily separate from the blade, since the surface of the bevel is relatively small. This way the fish stays on the board and you can make several very precise cuts with a minimum of rearranging.

The other application is the wood chisel used for planing. Here again is the purpose to push the separated material to one side and leave room for the blade for further progress. Similar are the blades in paper cutting machines. The push vertically through a pile of paper and leave a perfectly straight cut while pushing the waste to one side.

And don’t forget scissors. Both arms (legs?) of the scissors are basically chisel ground blades. They are that way because the have to slice along each other in order to give a clean cut.

In short, the idea is always to separate a smaller, flexible piece from a bigger, stationary piece. If you have this situation, the chisel ground blade does an excellent job.

If the idea is to cut something which is stable on both sides, you’ll be better off with a symmetrical, thin profile knife, which doesn’t have to push the material too far aside. Take a look at traditional hunting, skinning, boning, filleting, etc. knives. They are mostly thin and symmetrical ground to achieve their goal.

And the weapon of choice for penetrating armor was NEVER a chisel ground blade nor had it a (geometric) tanto point. That alone tells me that the advantage can’t be that great otherwise our very inventive ancestors would have produced and used them for battle.

Sharpening the chisel ground is another problem. Since the angle of the edge is very steep even a slight wear will decrease cutting ability significantly. And if there is no secondary bevel, you have to take the material from the entire surface of the primary bevel to keep the angle at where it was. This might be easy with a belt grinder, but doing it by hand or in the field is not quite my idea of having fun.

Sometimes me think that some people might be better off with a sharpened screwdriver for what they want their knife to do. But those shouldn’t be allowed in this forum
wink.gif
 
The "modern" cavalry saber is derived from the Hungarian cavalry saber. The Hungarian saber was often chisel ground. I don't know if the intent was to discourage the blade from deflecting back towards the user's horse when swinging at a helmeted enemy.

I tend to agree that a chisel works best slicing a flexible slice off a solid base. The only chisel ground knives I use are for slicing bread and cheese. A chisel grind works great for cheese.
 
Ralf,

I have made several chisel ground knives and don't see why people have trouble sharpening them. I can take a dull blade and put a scary
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shaving edge on them within a minutes time. I don't use a grinder or any other machine to put this edge on. Just sandpaper and a little elbow grease. They are a lot easier to sharpen than a conventional grind.

I use a chisel ground blade in my shop that has gone thru a 2x2 oak board and still shaves. And that blade is of 440C.
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If a man can keep alert and imaginative, an error is a possibility, a chance at something new; to him, wandering and wondering are a part of the same process. He is most mistaken, most in error, whenever he quits exploring.

William Least Heat Moon
 
uh.... sand paper can be used to sharpen a knife? If it is, I want to learn how
smile.gif


thanks,
chang
 
Comrade Chang,

I only use sandpaper for sharpening chisel grinds. It does not work too well on other types of grinds.

I take a sheet of 100 grit paper, spray adhesive on the back, stick that to a plate I have mounted to the vise and lay the bevel edge flat on it to sharpen. Works fantastic. I then remove the burr with a leather strop.

I try not to go any higher on the grit. 100 grit leaves a micro serration on the edge that really bites into the cut. Especially on fabric and skin. I have firsthand experience on the skin part (cut my fingers on several ocassions
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If a man can keep alert and imaginative, an error is a possibility, a chance at something new; to him, wandering and wondering are a part of the same process. He is most mistaken, most in error, whenever he quits exploring.

William Least Heat Moon


[This message has been edited by Phillip Jones (edited 01-04-2000).]
 
You can also just use card board to get the burr off the flat portion of the edge if you don't have a leather strop.

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Cerulean

What the hammer? what the chain?
In what furnace was thy brain? - Blake
 
On the Tanto that I made I finished the edge so there is no secondary bevel, and used a narrow board with strip sand paper tacked to it, 240 grit I believe, it took forever to get the initial bevel down. I C clamped the blade to a board leaving the edge of the knife overhanging slightly and worked the wood/sandpaper as a file. Very very sharp, I've chopped through tree branches quite easily and haven't had to resharpened the blade at all. Finished up the edge on a strop as well.
RJ Martin uses a buffing wheel set up to resharpen his knives and that would work well on the chisel edge knives, but I'd agree that's not an easy field sharpening chore.

G2

------------------
"There are no dangerous weapons;
there are only dangerous men."
.......... Robert A. Heinlein, 1959


G2 Leatherworks
 
Hi there,

Actually You're right, chisel is not the traditional Japanese samurai sword grind, but there has been chisel ground blades. I believe both the Kata-kiri-ba and Kata-shinogi grinds would classify as chisel. These have been popular during two periods (Kamakura : 1192-1335 and Azuchi-momoyama : 1575-1605), but only on shorter swords.

Best wishes, Staba-san

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Whereof one cannot speak, thereof one must be silent. - Wittgenstein


 
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