Advantages/disadvantages of a 1 sided bevel.

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_Muad'dib_

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So I was looking in Blades Knife Book and of the knives, a tanto I believe, has a one sided bevel/grind on it. What are the advantages of this? Disadvantages? Does it make the entire blade stronger or weaker? What would you more likely use a 1 side beveled knife for? I'm considering trying it on my second knife. Thanks for the help
 
It's called a chisel grind. It allows one side of the knife to cut flush against the material. It also allows thinner slicing in some situations.

Some Japanese kitchen knives will have asymmetrical grinds. As well, knives designed for prying will have chisel grinds.

Disadvantages include being a little uglier. As far as sharpening, it's like sharpening scissors. You only have one side to sharpen. However, you would sharpen the entire bevel, not just the edge.
 
One advantage is seen in high-end sushi knives. Though, those are technically ground on both sides, but one side is truly concave, like the relief cut on some drill bits, but straight.

This lets the knife not vacuum-stick to the main block of fish as it slices off a, well, slice. :D
 
zaph1 said:
It's called a chisel grind. It allows one side of the knife to cut flush against the material. It also allows thinner slicing in some situations.

Some Japanese kitchen knives will have asymmetrical grinds. As well, knives designed for prying will have chisel grinds.

Disadvantages include being a little uglier. As far as sharpening, it's like sharpening scissors. You only have one side to sharpen. However, you would sharpen the entire bevel, not just the edge.
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So if it's used for prying that would mean it's stronger than a standard double bevel?

I was also wondering if you ground it in a chisel style, but stopped about a 1/8 of an inch from the blade edge and then sharpened both sides, would that allow you to sharpen using normal methods? What's wrong with that idea? Does it just make for an ugly knife?

Thanks for the help so far.
 
Advantages of the Chisel Grind

High strength grind, this is mainly because a full chisel grind leaves a lot of steel, with a zero edge you will have a very strong and sharp knife - EDIT look at post #18
Easy to sharpen - I maintain mine by stropping the "back" of the grind
Zero bevel geometry on the unground side makes for an even cut with little resistance
When slicing food it falls to the correct side and your pivot finger rests against a smooth surface

I feel that a chisel ground knife works very well for cutting way from myself. When you cut towards yourself they don't work as well until you are used to increasing the cut angle.

I was used to sharpening my carpenters pencil with a utility knife, the first time I used a chisel ground knife I cut the top of the pencil off!

You can microbevel the back or grind asymmetrically if you like. The back bevel adds strength but steepens the effective cutting angle. I'm making a kiridashi out of 1/4" which will get a asymmetrical grind, it will work very well on this particular knife.

I make mostly chisel ground knives, after using regular ground knives most of my life I now prefer the chisel grind for my own knives, I prefer the way they cut.
 
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I just remembered another question I had. Are most chisel grinds a full sided flat grind or would you maybe just grind say 1/2 the blade?
 
A single edge grind means the blade pulls to one side when cutting and micro sharpening the back side is not the easiest thing for the usual user to do. Frank
 
ok as far as strength all the "facts" are now false

FACT a grind that has the same total angle ground to the same edge thickness (then honed to the same total angle of 2ndary bevel ) will have the same strength as a double bevel

guys 15 degrees is 15 degrees no matter what angle it is in relation to the grip of the blade ( i have had to go over this with more then a few kitchen knife ppl )
and yes the single bevel kitche knives are hollow ground on the back but on a large wheel 36-48 inch most of the time
i made up this quick sketch of a few blade profiles
dsc06596sm.jpg


now when you are slicing for sushi you have a crazy thin "cut side" that will not cause wedging of the blade or make the blade try to turn during the cut (single bevels are prone to a arcing cut) double bevels depending on how thick the grind can and do wedge in some cuts but in the thin slice type they do not (tho there can be drag from not having a hollow back )

problem is that there are next to no makers hollowing the back of "tac tee cool" knives so the bennies of lower drag are lost and all your left with is a wedge ground that is off set to the handle
 
I need me one of them there tac tee cool knives with the jimping and the spoon attachment and the built in sun dial.
 
butcher_block said:
ok as far as strength all the "facts" are now false

FACT a grind that has the same total angle ground to the same edge thickness (then honed to the same total angle of 2ndary bevel ) will have the same strength as a double bevel

guys 15 degrees is 15 degrees no matter what angle it is in relation to the grip of the blade
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Thank you Butch.

I've been telling people that for years.
 
Frank Niro said:
One sided grinds are extremely difficult to proprerly sharpen. Frank
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Why? Frank, you know I respect you, but I disagree. With a chisel grind we have two planes coming together to form a keen edge... no different than any other edge. I don't find it any easier or more difficult to sharpen a chisel, hunting knife, chopper or lawnmower blade.

Danbo said:
They're easier to grind.
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Not in my experience. You still have to be just as accurate as when grinding a typical full-flat, maybe even more since you can't fudge on where the middle is. I'm certainly not saying this about you, Danbo, but I've noticed that most folks who claim chisel- or scandi-grinds are easy to grind and sharpen come up with blunt slabs that I doubt would cut a juicy fart.

_Muad'dib_ said:
I was also wondering if you ground it in a chisel style, but stopped about a 1/8 of an inch from the blade edge and then sharpened both sides, would that allow you to sharpen using normal methods? What's wrong with that idea?
Click to expand...

You'd be poorly approximating a Japanese sushi-knife grind... sort of, but not really. Six of one and half a dozen of the other, with none of the benefits of either.

Butch and Fellhoelter are absolutely correct, a chisel grind is no stronger or weaker than any other grind with the same degree bevel.

Chisels are meant to cut in one direction exclusively. I continue to be puzzled why this is so difficult to understand. Just like Butch's drawings, take some paper and a protractor and prove it to yourself. Even more so, I'm flummoxed that some folks make chisel-ground knives with the bevel on the left, for right-handed people :confused:

The cross-section of any given blade has far more impact on how it will cut than any other factor. If more people spent some time thinking about that, we'd have a lot fewer clumsy knives floating around.
 
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I'm super new to all this so when you say the cross-section has more impact than any other factor what do you mean by both the statement and what does "cross-section" mean?

Here is what I'm hearing about chisel vs x- they both have the same actual edge strength, but a chisel would have a overal higher blade strength because it has more steel, correct? Or is there not enough of a difference to even matter?

The main benefit to a chisel grind, apart from the ease of the grind for a knifemaker, would be extra strength in the overall blade. A chisel seems more beneficial to a chopping/prying/super heavy duty type blade(if you aren't going to hollow out the other side, sushi style)
 
There is No More Steel in a chisel than a double bevel.
I think there is actually microscopically more steel in a double bevel, but the difference is negligible.

Cross section is the view of looking at the V shape.
Say like you snapped a blade in the middle, and looked at it from where the tip used to be...

After Blade, I'll draw up some cross sections in CAD, and demonstrate.
 
Alright, I had 10 minutes to kill so I drew up some cross sections.

These are all the same imaginary piece of material, in green.
A 1" tall, .250" thick piece of steel for the sake of clarity.

I drew 4 imaginary bevels.
A zero ground chisel, a zero ground double bevel, a chisel with a .010" edge thickness before sharpening, and a double bevel with the same .010" edge.
All of them are full flat grinds.

You can see the difference in the angles.
It's miniscule, and means very little in cross sectional area, and total volume of steel, but there is a difference.
And, the difference is in favor of a double bevel.
A bigger angle means more steel.

Bevels.jpg
 
I stayed away from this thread ,but feel compelled to wade in. There are few topics that can get more opinions than edge shapes and grind advantages.

First - As moderator, I would suggest that those who don't really know, or are just reciting what they have read somewhere, refrain from technical questions and let those with hands on experience answer the question.On this forum, there are people who deal with single sided grinds daily ( one is the best in the business). Let them answer these questions and the info given will be far more accurate.

Now, from me-
A single bevel, scandi, chisel, or hollow grind ....or any grind.....at 15 degrees is 15 degrees. None is thinner, sharper, or thicker than the other .......at the edge.

The grind mainly controls how thick the blade is behind the edge. A hollow grind removes some of that, but still has a double bevel ( primary and secondary), thus having a moderately strong edge with reduced cutting friction. A flat grind is the same with more behind the edge, and a convex has even more niku ( meat) . All these are just factors of edge impact resistance and cutting friction, and the edge is still the same.

If the blade is a full flat grind or a single sided grind ( chisel), then the edge is nothing but the apex of the triangle formed by the spine and the bevels, as fellhoelter pointed out. The amount of thickness is identical on a full flat or a chisel grind. The only difference between the two is the angle of attack on the edge ( compared to the centerline of the blade) and the fact that one forms an isosceles triangle and the other forms a right triangle. Otherwise a full flat grind and a chisel grind are the same.They both have very thin edge angles and are superb slicers. They both have delicate edges that can be damaged easily and are harder to re-sharpen if damaged. On a knife, they both cut soft things straight. Cutting on hard objects is a different thing, and a chisel grind is only an advantage in woodworking. When used on hard objects like wood chisels and metal gravers there is usually micro-secondary bevel on the backside.

So, why make a chisel grind knife if it is the same as a full flat grind ????
The main advantages of both are in the ability to slice meats and soft things very thin. The chisel grind has the advantage of only needing one side ground to maintain the edge. You sharpen the BACK by laying it flat on the stone and lapping it until the edge is restored.....no angles to figure out and maintain. On a full flat grind you have to do that to both sides. Unless there is some major restoration of the edge needed, you rarely need to lap the bevel side of a chisel grind, beyond a stroke or two to remove the wire.
Some higher end Japanese knives have the back ground as a large diameter hollow grind. This is not a grind to the edge, but serves as a reduction of the amount of metal needed to re-sharpen the knife. The only metal removed in re-sharpening a "hollow back" is a small strip along the edge. Every re-sharpening slowly raises this line, and you can often tell the age and amount of use by how wide the flat area above the edge is on the back. The prime advantage of this is to speed up and simplify re-sharpening.
If you have a large radius platen, you should start a chisel grind knife by doing a wide hollow grind on the back first. If you don't, then just flat grind both sides .

BTW, the bevel side is usually ground 1/2 to 3/4 of the way up the side. It will determine the overall edge angle, so the higher the grind, the sharper the knife. The blade thickness is the other factor that controls the edge angle on these type of knives. A deba is far thicker than a sashimi, and thus can be used for much heavier cutting.Thus, a sashimi blade is thin, chisel ground ( or hollow backed), and super sharp. Doing a chisel grind on a camp knife is just for looks, as there is no reason for it.

The myth that a flat grind will make the slice stick to the blade and a hollow grind will release it is about 99% sales hype. Knife control will handle any slicing situation. Watch a good sushi chef cut thin slices of hirame and you will see how to handle the sticking problems.

On a standard double bevel, you have to try and guess at the angle between the blade and the stone....and maintain it throughout the stroke...for the entire blade edge...on both sides. See what the advantage of a single bevel full flat grind ( chisel grind ) is now?
 
james terrio said:
I'm flummoxed that some folks make chisel-ground knives with the bevel on the left, for right-handed people :confused:
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thats easy no one wants to see jsut a flat edge on the "face" side of a blade however in japan they are not nearly as hung up on looks and have been using single bevels for knives for a long time (we are used to seeing a bevel cut on the face side frommm the use of double bevels)

other things to remember that if you are under about 15 degrees total angle you will likely need a 2ndary honed angle (learned this from straight razors and how the edge just falls apart under 15 with jsut about every steel i have tried )
i ll tru and get a few pictures of the sushi knives i have made (front and back) along with the tuna sword to show a bit of how things look when honed
 
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