Chisel-ground edges questions- understanding and sharpening

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wvdavidr

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Mar 21, 2007
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I have been told (and read) that chisel-ground edges are potentially sharper than conventional edges. My only experience (other than exacto knives) is with knives that were so bad that the grind was irrelevant. Is the idea that the one side is ground to a low angle (maybe 20) so that the inclusive angle is lower than the typical 30-40 inclusive that we are used to?

When sharpening, is it just sharpening to burr, refining, and stropping the ground side and stropping the flat side?

FWIW, I'm interested in these mostly for kitchen use.

Thanks,
Dave
 
Hi,
wvdavidr said:
I have been told (and read) that chisel-ground edges are potentially sharper than conventional edges. My only experience (other than exacto knives) is with knives that were so bad that the grind was irrelevant. Is the idea that the one side is ground to a low angle (maybe 20) so that the inclusive angle is lower than the typical 30-40 inclusive that we are used to?
Click to expand...

I think the idea is chit-chat :)
Japanese knives are commonly thinner at the edge and lower angles, and some of them have chisel/asymmetric edges ...


I have also read Chisel grinds are stronger and that its not true as they're unbalanced (steering, unbalanced lateral loads)



wvdavidr said:
When sharpening, is it just sharpening to burr, refining, and stropping the ground side and stropping the flat side?
FWIW, I'm interested in these mostly for kitchen use.
Click to expand...
Yup, sharpen like a regular knife
you can see some wood workers just raise a burr, then strop to remove burr


But for domestic kitchen knives I don't really see the appeal
at least when it comes to small paring knives which come with chisel ground,

I guess it helps to have the apple/potato peel go off to the side more forcefully,
but I've never found that too be important.

Also they're all left handed chisel grind ,
ok if you peel stuff toward yourself,
but if you cut the regular way the steering is in the wrong direction for right handed use .
a regular/balanced blade doesn't have steering/bias so use as you like with equal comfort

there might be some advantage for chopping veggies ... or sushi or such? ... but plenty french/european style chef knives do that kind of work without problems and they're not chisel ground ... choices choices :D
 
I think chisel ground blades are said to be sharper for a couple of reasons: First, they are usually (but not always) ground to low angles. This makes them sharper just because the edge is thinner. Second, a lot of Japanese blades are chisel ground, and Japanese blades have good geometries. I.E., the designers design them for high performance and they work! They just *happen* to be chisel ground, which probably has very little bearing on their performance. They just have good overall geometry.

Your outline of sharpening a chisel ground blade is essentially correct. It's just like any other blade, except that you don't want to do any real grinding on the flat side. Sometimes you have to do more that "just strop" on the flat side in order to remove large burrs, but that's not difficult. Just hold the blade at a very small angle to the stone (almost completely flat, but not quite flat) and do a few strokes to remove the burr.

Brian.
 
My take is that chisel grind are "sharper" only because they are easier to sharpen freehand.

Let's say you have two degrees of variation in your pass, for a 4° total. On a chisel you halve that. If your deviation is 1 degree per side, then it winds up 1°.

As for sharpening them, I will only only strop the flat side if its a very hard strop. Otherwise I grind the bevel side, grind the flat side to push the burr over and all my burr cleanup efforts are on the bevel side. Making corrections to the flat on a chisel grind is a lot of work, so once its flat I try to leave it alone as much as practical.

I believe on the Japanese single bevel all the heavy work is done on the bevel side with very little work on the flat (concave) side being done with anything more aggressive than a medium grit stone - unless the concave needs correcting but that requires some specific gear.
 
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