chisel grind question

[Jared Stenoien]

ok...i know everyone says chisel grinds are sharper etc. but how does this work? i'm talking about flatgrinds, not hollow or convex (which flatgrinds are usually what i see anyways) if you have a 1/8" knife and a 1" wide bevel, it doesnt matter if you do a chisel grind or normal flat grind, you still get a total angle of about 17.5 degrees, sooo...whats the point? is there something i'm missing?

 

[Airborne Steel]

Only one side of the material you are cutting is causing drag on the blade?

 

[novaflare]

ok...i know everyone says chisel grinds are sharper etc. but how does this work? i'm talking about flatgrinds, not hollow or convex (which flatgrinds are usually what i see anyways) if you have a 1/8" knife and a 1" wide bevel, it doesnt matter if you do a chisel grind or normal flat grind, you still get a total angle of about 17.5 degrees, sooo...whats the point? is there something i'm missing?

Well i wouldnt know about the whole they can be gotten sharper than a non chisel grind. But from my own experiance i can put a razor ede on a chisle ground blade alot easyers than on a non chisel. My friend down the street can get pretty much any knife razor sharp to the point where it will cut you if you look at it wrong.

With a chisel grind when you sharpen it you really dont have to touch the other side unless you need to remove a burr and then its a simple matter of a single stroke.

One guy where i bought a custom made knife years ago showed me a knife he made that had the chisel grind but he did something quite unusal. On what would normally be the flat side he put a very shallow hollow grind to the edge. The knifes edge was just crazy sharp and very easy to sharpen.
He said they way he sharpens the knife is to simply lay the flat side flat on the stone and do a couple strokes.

That makes alot of sense to me as simply put if you have your angle on the ground side already set then by removing the other sides material by sharpening you keep that perfect angle always.
What was realy neat is it was a spear point style blade. I tried really hard to talk him out of that one of a kind knife but no such luck ahh well such is life sometimes.

 

[fitzo]

mrstenoien, don't confuse primary bevel angle with edge bevel angle. While 17.5 may be the main bevel angle, typical Western edge bevels are 22.5-25 degrees or so. An actual angle of 17.5 would be very acute and produce a sharper edge.

Another point is whether a chisel grind has a "zero edge" as in many Japanese cooking knives. When the primary bevel goes all the way to the edge (no secondary bevel), then you have a much more acute edge angle, and they get very sharp. Rather than sharpening just an edge, the entire bevel is placed on the stone. This is common in many Scandavian blades, too. The downside, of course, is that there is less steel behind the edge and they are not as strong, rolling easier.

Nova, the one side chisel ground, one side hollow ground zero edge is a traditional Japanese knife grind. You are right about how sharp they get. My wife shaved a fingertip recently with one and didn't even know until the blood was wetting the veggies.

 

[DevilMan]

I know I can search for it and I will but I'll ask here as well.... I'm in the process of making a knife that I intend to put a chisel grind on. It is a very narrow knife and am wondering what angle I should put on it. I am also a newbie at this, though I have had knives my whole life, I still haven't really looked into or learned a Hollow Grind or COnvex Grind. I do want my knife SHARP.... and so I'm thinking and maybe it's just from being in japan that's why I was doing the chisel grind... but the Chisel Grind Hollow Ground Zero edge is what I want. I didn't know that the back of the blade had the hollow grind.

Can someone explain this?

Thanx in advance,

DM

From what I know or think I know... you have a chisel grind blade it's got 1 angle cut into the edge from edge tip up. To sharpen the knife instead of sharpening the whole ANGLED edge... You simply lay the blade flat and move the FLAT of the blade UP more into the CHISELED part of the blade. Is that considered a HOLLOW GRIND ZERO ANGLE???

Thanx.

 

[flatgrinder]

Chisel grinds are for sushi knives or chisels. I personally don't like them. The only thing good about them is that they're quick and easy to grind.

If you want sharp, try a thinly ground full convex grind.

 

[novaflare]

mrstenoien, don't confuse primary bevel angle with edge bevel angle. While 17.5 may be the main bevel angle, typical Western edge bevels are 22.5-25 degrees or so. An actual angle of 17.5 would be very acute and produce a sharper edge.

Another point is whether a chisel grind has a "zero edge" as in many Japanese cooking knives. When the primary bevel goes all the way to the edge (no secondary bevel), then you have a much more acute edge angle, and they get very sharp. Rather than sharpening just an edge, the entire bevel is placed on the stone. This is common in many Scandavian blades, too. The downside, of course, is that there is less steel behind the edge and they are not as strong, rolling easier.

Nova, the one side chisel ground, one side hollow ground zero edge is a traditional Japanese knife grind. You are right about how sharp they get. My wife shaved a fingertip recently with one and didn't even know until the blood was wetting the veggies.

Been there done that my self the whole shave a fingure aka pealing your fingure bit. Good thing is a sharp knife like that you have no visable scaring. So lucky for me my record still holds only got one cut scar from a knife.
Im one of those lucky few who instead of doing the whole fling the knife bit when you have a folder close on you i instead stop and reopen the knife never getting more than a nice clean cut.

Now i did drop a very sharp parker gypsy balisong and pinned my foot to the floor. Also snipped out a neat little hunk of meat out of my webbing between my thumb and pointer.

ON topic i my self love a chisel ground blade esp a tanto style. They just tend to keep a edge better even with lower quality steel than more traditional grinds. Get one with good steel and man it just lasts for ever.

 

[Jared Stenoien]

thanks fitzo, thats what I was wondering, and that chisel/hollow ground combo sounds wicked but that's also why I wasnt including hollow ground knives, an yes, I was talking about zero ground knives, should have made that clearer

 

[Stacy E. Apelt - Bladesmith]

To put it in a short and simple answer. (this is in approximate numbers)
A chisel grind is 1/2 of a regular grind,so it is twice as acute.If your normal primary bevel is 22 degrees, a chisel grind is 11 degrees.

 

[Jared Stenoien]

that's what i used to think too, but then i thought about it awhile and it didnt make sense, so i drew it up in autocad a bevel on 1/8" stock 1" up

that shows that a chisel grind isnt thinner than a flat grind, unless the chisel grind is twice as long as the flat grind or the stock is half as thick, which you could simply extend the flat grind or thin the stock for it, thus negating any benefit

 

[Whoever Wherever]

chisel grinds are not sharper nor do they have a thinner edge. I think they are a joke on most knives. On a japanese chefs knife they serve a purpose that fits with the grind. You chop against the tips of your fingers with the flat side, this also shaves the food off in the right direction. On a tactical folder I think they are a full on joke. Emersons claims that they offer tactical advatages have been rebuked countless times. Yes they can become sharp, this is a function of geometry and steel, not the chisel grind. A razor blade is sharper than any chisel grind and the ones I like have a dual side grind. The needles used to puncture the human body in hospitals also have a dual bevel. As for less drag I think this is BS to. Anyone who has cut boxes with both a chisel and a hollow grind will tell you the hollow binds less. Also on a soft target be it pork or a human (for those tactical knife nuts) the material bieng cut pushes in on the blade from both sides I really dont think having one of those angles at 90 degrees to the knives spine would create any reduction in drag whatsoever.

 

[novaflare]

chisel grinds are not sharper nor do they have a thinner edge. I think they are a joke on most knives. On a japanese chefs knife they serve a purpose that fits with the grind. You chop against the tips of your fingers with the flat side, this also shaves the food off in the right direction. On a tactical folder I think they are a full on joke. Emersons claims that they offer tactical advatages have been rebuked countless times. Yes they can become sharp, this is a function of geometry and steel, not the chisel grind. A razor blade is sharper than any chisel grind and the ones I like have a dual side grind. The needles used to puncture the human body in hospitals also have a dual bevel. As for less drag I think this is BS to. Anyone who has cut boxes with both a chisel and a hollow grind will tell you the hollow binds less. Also on a soft target be it pork or a human (for those tactical knife nuts) the material bieng cut pushes in on the blade from both sides I really dont think having one of those angles at 90 degrees to the knives spine would create any reduction in drag whatsoever.

As i said orriginally simply put they are easyer to sharpen to a razor edge because and only because you need to worry only about one side of the blade. Ive seen some higher end chisel ground blades that have right hand and left hand models. Right handed models have the grind on the left side of the blade when you have the point pointing away from you lefty knifes have it on the right side. Now pick up that knife there in front of you and act like you have it to a stone. Wich side is some what easyer to control the angle of? For right handers it will be the left side for left handers the right. Like the drawing indicates up a few posts a chisel ground blade also has more meat behind the endge than other grinds. This could make the edge last longer all else being equal.

 

[Jared Stenoien]

actually, the whole point of that picture is that a chisel grind has the exact same amount of steel behind the edge, if anything it'd be weaker since it is only supporded on one side when youre cutting

 

[Whoever Wherever]

What Mr. Stenoien said. I am very aware that Japanese kitchen knives have right and left handed versions. My father, who taught me to be a chef, is a leftie and I myslef favor the right. While I agree that having the chisel ground on the correct side helps the function it doesnt change my view on chisel grinds outside kitchen knive at all. Japanese chisel ground kitchen knives are a wonder to use. They produce finer slices than anything I have ever used or seen. They also would chip or break if used for the same things I use my european chefs knives for (bone, ect.). Thats because they are thin to achive such a razors edge, the chisel grind is used for the way the blade lays against the fingers and slices away from them, not for its ability to become a finer edge. Again the best quality razor blades (replacable not straight) and hypodermic needles both have a dual bevel and not a chisel grind, yes I know you can get chisel ground razors and needles. They are still sharp due to the thin metal but not as sharp as there well made counterparts. In a standard thichness folder blade or an even thicker "tactical blade" I think chisel grind sucks compared directly to a flat or hollow grind (each wich has its weakness in relation to eachother). R.J. Martins tantos are the best example of a chisel ground knife I have ever seen and I think I'd prefer a double hollow gorund one. I know some that would disagree with me on that point, but this is matter of personal opinion in the end. A good chisel ground knife of good stell is sharp and will cut. A chisel grind could be said to be easier to sharpen but only if you admit you are reprofiling the blade (if its a zero edge of course). But all these claims that it is somehow sharper or creates less drag in tactical stab wounds is just that, claims. From a manufacture standpoint its cheap to produce and here is where I think the chisel ground phenomenon took hold.

 

[Matthew Gregory]

that's what i used to think too, but then i thought about it awhile and it didnt make sense, so i drew it up in autocad a bevel on 1/8" stock 1" up

that shows that a chisel grind isnt thinner than a flat grind, unless the chisel grind is twice as long as the flat grind or the stock is half as thick, which you could simply extend the flat grind or thin the stock for it, thus negating any benefit

Hey, mrstenoien, would you mind running those autocad programs again, except this time place the chisel grind and 'v' grinds halfway down the 1/8" steel instead of all the way to the top? I'm not sure if this changes this observation or not, and I lack the mechanical aptitude to prove my own theory wrong. Thanks if you can pull it off!

...btw, one of these days you've got to explain your screen name to me.

 

[Whoever Wherever]

Id love to see one with a hollow on one side and a chisel on the other in addition if your going to autocad anymore If not that's cool, thanks for the first diagram.

 

[Jared Stenoien]

here they are

and now you can see why I didnt include hollow grinds in my question, not sure why the convex ground were a little different but i dont think youre going to see a difference if your blade is .15 degrees more acute but the way I measured the convex and hollow ground is I measured the angles of the tangent line .01" up on the bevel, obviously youre not going to zero grind a hollow ground knife but this data still applies. the "wheel" the hollows were ground on has a 10" diameter. also, my sn is simply Mr Stenoien, Stenoien is my last name, and I use mrstenoien for everything b/c it's one sn that is never taken!

 

[David Wesner]

Something just isn't jiving here mrstenoien. You can do it much more simply by just taking 2 pieces of paper the same size and folding to the corners (as in a grind to the spine).They are clearly not the same angle.

 

[Jared Stenoien]

try it, take a piece of paper and fold the corners like youre going to make an airplane, now take another sheet of paper the same size and from where the fold ends on the other side fold it all the way across instead of just to the middle, theyre the same size

 

[David Wesner]

I'm sorry mrstenoien,I just can't get mine to come out the same(with paper) . I found while trigging out the angle for a tapered tang a while back that due to the small dimensions (half the thickness of the stock)that the Hypotenuse was coming out the same length as the long leg of the triangle,I found this was due to the limited # of decimal places the software application would let me enter.I think and will agree with you, that for knife size pieces of steel the angles are essentially "the same". The bigger you go with your #'s is where the difference starts showing up.