Pros and cons of Hollow grind?

The general claim is that a hollow grind continues to "cut" even when the apex of the edge is dull because the hollow grind is thinner behind the edge than other grinds. I think this is largely true and for me, most noticeable when cutting materials that separate themselves upon being cut like rope or meat. I like a hollow grind on a hunting knife, for this reason.

I find hollow grinds do less well on materials that don't separate easily like slicing potatoes or battoning wood. I find that the sudden and typically sharp transition line at the top of the grind creates a point of drag. I find that full flat grinds or convex grinds tend to cut in these materials better.
 
Pros: thinner behind the edge while allowing for thicker spine= potentially a good cutting knife while maintaining some stoutness.


Cons: lowers cross section thickness and can lead to failures if used for chopping or other hard tasks.



All of that is a tiny portion of cons and pros and there are a million variables.
 
They cut relatively well. There is debate as to whether or not they get wedged into material once it reaches the shoulder of the grind.

Personally, I don't buy the notion that they get caught in anything more often then a comparable height flat grind. I've yet to see that proven empirically, but I'd welcome the documentation if it exists.
 
There are some who have found, through use, that a properly sharpened hollow grind with the correct geometry is the best chopper shape for them. It all comes down to specific knives and construction/materials.
 
High and deep hollow grinds cut very well and are easy to get to hair whittling sharp.They are good choice for fighting knife in my opinion as they cut meat and other soft materials way better than most other grinds.Too bad there isnt more full hollow ground knives ,that grind cuts any materials very well .
 
Hollow grinds have a higher degree of deflection at the top of the grind than flat or convex grinds, but are capable of achieving thinner geometry through the body of the blade than flat or convex grinds for a given spine thickness. In cutting soft materials that will readily move out of the way of the blade, they present less of a disadvantage over other grinds, but are a poor choice for more rigid materials as they'll tend to bind. They're less resistant to side loads and torque on the edge than other grinds since there just isn't as much material resisting the force. The larger the radius of the grind, the closer to a flat grind it becomes, and the less deflection at the plunge line you have. I really like shallow full hollow grinds, as they experience minimal wedging over flat grinds but manage to be thinner through the body, which results in excellent cutting performance. Small-radius hollow grinds are what most folks complain of with hollow grinds, as they wedge VERY badly in anything harder than raw meat, and are usually used for economy because a small-radius hollow grind can be applied to both sides of a piece of thin stock very rapidly with a single pass. This is why you see it so often on bottom-of-the-barrel kitchen knives. It's a manufacturing cheat that does the grind style a disservice. Douk-Douk knives, by contrast, are a great example of a subtle full-height hollow.
 
marrenmiller said:
Personally, I don't buy the notion that they get caught in anything more often then a comparable height flat grind. I've yet to see that proven empirically, but I'd welcome the documentation if it exists.
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I would be surprised if any real empirical study on this exists. The common test for edge retention is CARTA gel, which is too soft to cause the wedging issue and realistically only tests for edge retention at or near the cutting edge - which is to say, that hollow grinds actually have the advantage.

I have 3 Buck 110s. An old one from the seventies with a semi-hollow grind and rounded shoulders (more costly to produce). And I have 2 current models with a more traditional deep hollow grind and a very pronounced shoulder. One of these newer 110s, I put it to a course stone and I flattened off the the shoulders of the hollow grind.

It's almost immediately apparent when slicing up a few pounds of potatoes and rotating between the knives. The modern 110s make the initial cut much easier because they are thinner behind the edge (the old semi-hollow grind is actually thicker above the edge) but the old 110 and the modified new 110 slice all the way through the potatoes much more easily. There is considerably less drag.

Similarly, I had a Mora Companion HD that I convexed and it out battons my hollow grind Buck Reaper. Same thing. The should of the hollow grind binds up whereas the appleseed profile of the convexed Mora splits and goes through the wood faster. Again, side by side comparison of knives helps illuminate that.

NOTE: I'm not saying that you can't slice potatoes or split wood with hollow grinds. Obviously, you can.
 
There have been a couple of mentions of full hollow grinds; would anyone please suggest some examples (in addition to Douk-Douk-thanks FortyTwo). I'd like to know more about them (heck, I might have some-in addition to Douk-Douk :eek:).
 
Thanks Miso2, I have both of them and now, with the Douk-Douk, I have three to examine and experiment with. Mille Grazie! :D
 
Full flat grind is by far my favorite, great combo of slicing and edge strength (preference evidenced by the fact that all of my full customs are FFG) :thumbsup: Full hollow grind is something I have some of but never thought about (the Eskelibur seems to be so only on the front inch or so, but is wide enough that by the time you get to the spine you are through, love it :D). I knew certain knives (e.g. Douk-Douk, Eskelibur) were great slicers but now I know why. Thanks OP (and others like Miso2 and FortyTwo). I've seen diagrams and such (thank you all) but there's nothing like trying/comparing the various knives to figure out the dynamics (aside from the absolute fun factor :cool:). All these many years, and still learning-love it-and BF. :thumbsup:
 
I've always thought in the back of my mind that a hollow grind could be a self jigging knife for sharpening. Though I have never tried it. Picture how a razor is like this.

In theory one can plunk the knife down flat on the stone with the spine riding on one side and the sharpening bevel riding on the other side and just run the knife on the stone until it is apexed. Now a razor gets more complicated (as I understand it I have never sharpened a razor) in that one only uses the stone so far on a razor and stops short of apexing or a bur in any case and then go to the strop for the final edge.

Anybody sharpen their robust hollow ground EDC this way or is this pure fantasy on my part ? ? ? ?
 
Wowbagger said:
I've always thought in the back of my mind that a hollow grind could be a self jigging knife for sharpening. Though I have never tried it. Picture how a razor is like this.

In theory one can plunk the knife down flat on the stone with the spine riding on one side and the sharpening bevel riding on the other side and just run the knife on the stone until it is apexed. Now a razor gets more complicated (as I understand it I have never sharpened a razor) in that one only uses the stone so far on a razor and stops short of apexing or a bur in any case and then go to the strop for the final edge.

Anybody sharpen their robust hollow ground EDC this way or is this pure fantasy on my part ? ? ? ?
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Most hollow grinds the edge isn’t angled in such a way that you could just lay the knife on the flat of the side and have the edge contact the stone.

However Miltner Adams has a grind he calls the HollowFlat which allows for exactly what you describe.

hollowflat-blade.jpg
 
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