GLOOB weighs forth on the Hollow Grind


December 21, 2013, 10:37 PM
Steel behind the bevel increases the stress required to push the edge out of line (rippling), not only laterally, but in-toward the spine.
This is all true. But it has nothing to do with edge strength.

If you want to consider rippling, you also have to consider than when your edge hits something hard, some elasticity/flexibility of that edge may prevent it from failing, too.

As for pressure inwards towards the spine, yes. If you have a very long skinny knife, it may break if you whack it over a log. That's blade integrity, not edge strength. And you can make up for this with blade breadth, as well as thickness of the spine behind the hollow grind.

When you are talking about edge strength and what supports that edge, that would be covered by the first millimeter of the steel. This is where you get chips and rolls. Judiciously grinding away some "dead weight" behind this area won't magically make that edge start to fail. If it worked before, it will work after. I mean, unless it's the little straw that broke the camel's back. Because the primary grind has about as much to do with edge strength as does the price of tea in China.

If you enjoyed reading about "GLOOB weighs forth on the Hollow Grind" here in archive, you'll LOVE our community. Come join today for the full version!
December 22, 2013, 04:21 PM
The primary benefit of a hollow grind is ease of sharpening and weight reduction. For someone who knows how to "free-angle" sharpen a knife, the hollow grind is ideal. It took me about 20 seconds to completely reprofile the secondary bevel on my hollowground Kershaw and Sodbuster knives on the belt sander. It took over half an hour to do the same to my Peasant knife. When time comes to thin out the edge, again, the hollowgrinds will be much faster, once again. The area of secondary bevel is much smaller, plus there is no need to try to either straighten the grind line or blend in the bevel with the rest of the blade, nor to remove scratches.

The weight reduction is the same idea behind an I-beam. If you could build a knife blade such that you could put the steel only where it's going to do the the knife the most good, you would end up with something that resembles a hollow primary grind. If it weren't for an axe needing the weight, anyway, you could also do something resembling a fat hollow grind on an axe, too. Well, in a way, an axe has a hollow grind primary, already, because of how it is affixed onto the handle.

Compare the mess of a wrecking bar in post #10 with this.
I had a Buck knife almost exactly like this when I was a teen. In fact, I think it was the same model number and exactly same handle material, but I think they refined the shape of the hollow grind. (I recall mine looking more simple.) As you can see, Buck has made this knife easier to sharpen while leaving LOTS of meat behind the blade. You can put as fat a convex edge on this knife as you'd like, in case you want to use this knife as an axe.

Difference between Buck and some other master knifemakers, is that Buck knows how to make knives AND they have CNC grinding machines, AND they sell enough knives to make it worth the time to set up said machines. It's not at all a necessity. It's more just a nice added touch that in no way restricts the capabilities of the knife. If I were making limited quantities of custom knives, I wouldn't bother with a hollowgrind, either, even if I had the equipment.

Take your fully convexed knife with fat chopper edge and cover it with sharpie. Go fell a tree. What you will find is that there is a huge area of the blade that does not come into significant contact with the wood. (The splitting "wedge" effect is created by a very small part of the blade close to the edge.) If you dished out this untouched area a little, it would have no significant impact on the knife's performance. It wouldn't make the edge "super thin, hollow ground, and great for slicing." It wouldn't make the knife "stick in wood or food." It wouldn't make the edge more fragile. All it does is removes a little weight and makes the knife easier to sharpen.

December 22, 2013, 04:57 PM
I see a mod has started a new thread for me with a catchy title. Apologies for derailing the previous thread.

Sam Cade
December 22, 2013, 05:07 PM
No worries bro.

I'm the worst for digression. :o

December 23, 2013, 02:53 PM
Hollow ground blades are easy to sharpen at home where you have access to large sharpening stones or whatever. Out in the bush it is another story. Tiny little stones like you see on the sheath of a Randall require good lighting and a steady surface to touch up an edge.

Scandi grinds can easily be touched up with a pocket stone and convex grinds stropped with your leather belt. That is what I have found anyway.

If you enjoyed reading about "GLOOB weighs forth on the Hollow Grind" here in archive, you'll LOVE our community. Come join today for the full version!