“Discovered” the Hollow Grind WOW!

[marrenmiller]

I can cut transparent, paper thin slices of tomato with my chef's knives. Is that better than a hollow grind would be? I don't know but it works pretty darned well for me.

If you could hollow grind a chef's knife effectively, then I bet it would be a little better. It's not practical, as I alluded to earlier, but that doesn't mean that hollow grinds are worse.

 

[marrenmiller]

I didn't say there was anything wrong with it. I said that I don't care.

No one is advocating EDC-ing an axe to cut your apple at lunch and open your Amazon box after dinner. "Geometry" (that's the first time I've ever used that word on BF) would certainly matter in that context. As between an FFG Endura and a hollow grind Buck 110, however, there is virtually no substantive difference in cutting ability for the average user. If anything, most users would prolly prefer to kill a cardboard box with an Endura over a Buck 110, as the latter's hollow grind has to "part the waters" more the FFG Endura. And we would take an Opinel or Swiss Army Knife over either both.

But I have no stake in the game. I just don't care, except that she's sharp.

Sharp.

You say you don't care, but all the knives you mentioned have relatively good cutting geometry. It looks like you care somewhat, unless you'd be fine cutting with a Medford or something.

 

[pinnah]

That's a fair point, but it's equally fair to point out that this comparison between grind types is only fair for a given edge thickness, primary grind height, edge angle, and stock thickness. Saying a thin Opinel outslices a Sebenza is likely true but says nothing about the merits of hollow grinds as a category.

Sure. Couple of points.

Hollow grind is a very broad category and primary grind is only one of many factors.

I think of slicing as the ability to go through non-self-separating material. Potatoes, apples, butternut squash are examples as is cardboard.

I find that meat and rope is more about cutting, since those materials separate on their own. That's mostly about what happens at the edge apex and blade geometry above that has little influence.

When I want to compare blades, I consider blade height and thickness. In my mind I think of an Icoselese triangle formed by the spine and apex. A full flat grind matches this almost exactly. A full height hollow would fit inside of this triangle and a normal hollow grind like a Buck 110 or Sebenza has a significant amount outside of this triangle from the spine to the shoulder.

Convex blades and Sabre flat grinds also have portions outside the Imaginary triangle formed by the spine/apex.

IME, slicing is influenced by how far down the bulge comes and how sharp the grind line is.

Take a Mora and convex off the shoulder and it will slice a bit better mostly due to a reduction in drag.

Take a Buck 110 and entirely scrub off the shoulder so that th top part is similar to a full flat (matches the imaginary triangle) and the slicing ability dramatically improves.

Making a blade taller or thinner effectively makes the natural wedge of the blade more acute.

 

[marrenmiller]

That's a great way to think about it, especially as you indicate that some materials aren't dependent on the grind at all. When I think of blade grind performance, I am always thinking of food (apples/potatoes/onions/etc), firm elastic material, or of cardboard. I think a lot of people must think of meat or paper, or of some other medium that does not depend on the grind, and that can obfuscate these conversations sometimes.

I contend that, with most items people cut with their knives, a full hollow (which isn't comically deep, though these kinds of grinds aren't common) will likely have less drag than an equivalent full flat grind, given the same conditions (blade height, stock thickness, edge thickness, and edge angle/finish).

 

[Mitchell Knives]

Can you list some value-oriented knives with hollow grinds done right?

I purchased a Case Stockman (with a wharncliffe blade in place of the spey) and both blades had a nice full height hollow grind.

The blades are probably around .07" thick which works great for this kind of grind.

 

[Mitchell Knives]

I contend that, with most items people cut with their knives, a full hollow (which isn't comically deep, though these kinds of grinds aren't common) will likely have less drag than an equivalent full flat grind, given the same conditions (blade height, stock thickness, edge thickness, and edge angle/finish).

I would concur.

I think that we can all agree the minimizing drag between the blade and the material being cut will increase cutting performance, all other things being equal. There will always be drag at the actual cutting edge. Little can be done about that except changing the geometry to reduce the amount of drag. There is also drag along the width of the blade itself. (Assuming you are cutting a material that is thicker than the width of the blade.)

On a flat grind there would be drag at the cutting edge and along the entire sides of the blade up to the spine where the grind terminates.

On a full hollow grind there would be drag at the cutting edge and at the spine where the grind terminates. Little to no drag would occur along the area within the hollow.

On some of my knives I'll grind a swedge to not only aid penetration but to lower the "drag point" of the blade.

A good general rule is that if you are cutting something that isn't as wide as the height of the grind itself, a hollow grind tends to work better. If the material being cut is thicker than the height of the grind, go with a flat or full hollow.

 

[Natlek]

Personally I don't get the point of hollow grind other than perhaps weight saving. A FFG with great geometry and thin behind the edge is IMO at least a match with shallow slicing and is superior overall due to its additional strength and versatility.

HG vs FFG is an almost religious debate though. You're not going to get many who will agree either way.

FFG can be thin ONLY behind edge ................hollow wins

 

[justjed]

Proper cutting technique is more important than blade grind. Or blade steel. You can do amazing things with one knife if that's all you have, provided you are smart about what, and how, you cut.