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Post by Student of Sword on Dec 22, 2010 7:55:33 GMT
Why are so many knives I have seen (custom and production) are hollow ground?
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Post by Vincent Dolan on Dec 22, 2010 8:30:04 GMT
This is just my personal opinion on the matter, so take it with a grain of salt, but I believe the main reason most knives are hollow ground is two-fold: one, it produces a much narrower edge, so it cuts smoother and easier and two, it looks very striking, aesthetically speaking; it throws the flat and any fullers into sharp relief. Again, that's just my take, but it makes sense to me.
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Post by Tendrax on Dec 22, 2010 9:03:16 GMT
Because it's sharp? Sorry, I don't understand the question. Keeping in mind that a knife is not a sword, and that secondary bevels are much easier to sharpen, there aren't really any downsides to a hollow grind. It also lightens the knife up a bit without sacrificing much strength, same as a fuller.
Why not a hollow grind? I mean I prefer a full flat grind myself. It tends to slice through things and split wood a bit better, but the difference is barely noticeable. I certainly wouldn't hesitate to use a knife with a hollow grind though.
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Post by Student of Sword on Dec 22, 2010 9:07:26 GMT
So what is considered to be bad geometry in a sword is not neccessary bad in a knife?
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Post by Tendrax on Dec 22, 2010 9:19:13 GMT
No, it's not. It's like comparing a claw hammer to a war hammer. Same basic design, but totally different when you get down to the specific details.
If you're a person that actually uses your knives, I can guarantee you it's going to go dull faster than any of your swords, no matter how much cutting you do. Cardboard, paper, tape, glue, wood. All of these things dull an edge very quickly, so it's more beneficial to have an edge you can quickly touch up. Sharpening convex edges(apple seed edge, or for a katana, a blade with... Niku, I think it is) is a complete P.I.A, and most knife user's wouldn't bother. However secondary bevels, you just toss a couple of quick passes over a diamond rod, or a whet stone, and you're good to go. I have a lot of knives, only one with a convex edge. I used it for a while and it got dull, so I tried to sharpen it. It took forever, and once I got it sharp, I never used it again. That's typical of your average knife user.
At this point I tried to explain the differences between the edges and their intended use, but I'm failing to put it into words. Sorry, I should have gone to bed hours ago. Lol.
I really need to go to sleep now. Maybe someone else can chime in who is a bit better with these word things. :lol:
[EDIT: Maybe this will make sense. A sword needs to slash through a target, at fairly high speeds, and not get caught up by drag through the target. On a knife, drag through the target is irrelevant, because you're in 100% control of it the entire time. It doesn't cut until you want it to, because you have to push it through the target. Where as with a sword, once you swing it, anything within range of that swing will get cut.
You also have to keep in mind the kinds of steels and size of the blade. A hollow grind makes a very thin blade, which in a high carbon sword would be to brittle, but in a blade less than 12 inches, it doesn't matter. It's never really going to flex either way. I hope this made sense. Maybe in the morning my brain will work better. Sorry if I wasn't as helpful as I could have been. Lol.]
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Post by vince on Dec 22, 2010 22:18:35 GMT
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Post by Tendrax on Dec 23, 2010 4:48:35 GMT
Interesting read,but I'm not sure I really agree with all of it. I've found through personal use my full flat ground blades offer A LOT less resistance in the cut then any of my hollow ground blades. However, a lot of it could be based simply on the kinds of things I cut with my knives. Mostly cardboard and tape, and almost no food or other things that would be laid flat and sliced. That said, a flat grind that stops halfway up the blade is the worst thing ever, because it makes a very wide edge profile and gets hung up in stuff pretty easily.
Also, you'd have to sharpen a blade a few million times to get any where near the amount of metal removed in his diagrams. I mean, the difference between the first and last of each diagram is like comparing a 30 year old, hard used knife to when it was new, which for most people is irrelevant. They're going to lose it, break it, buy a new one, or stop carrying it all together long before they get to that point.
However, realistically these differences are pretty minor, and any knife blade made out of a good steel with a good heat treat will serve just fine for anything you'd need it for. The major factors for use are profile shapes and blade lengths, as well as folding vs fixed blade. Those are the things that really dictate what a knife can be used for.
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Post by John Greybeard on Dec 26, 2010 2:24:39 GMT
The discussion here of different knife blade geometries is very valuable, a lot of good information. But with all due respect, I think the real reason most knives are hollow ground is a lot more prosaic - its the easiest to production grind on modern manufacturing equipment.
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Post by Tendrax on Dec 26, 2010 3:08:42 GMT
Oh yeah, most definitely. I was originally attempting to explain why it didn't matter as much for a knife edge, but it's one of those things where I totally understand it, but I have no idea how to really put it into words. Lol. So frustrating.
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Post by John Greybeard on Dec 26, 2010 3:24:14 GMT
hahahahahaha...... exactly, Tendrax!!! My problem leans more towards me finding all kinds of words for stuff that I don't understand at all....
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Post by GUEST on Dec 26, 2010 15:32:38 GMT
Don't see how hollow ground would be easier to grind on modern equipment Sabre grind would be the easiest to grind. You see alot on survival knives being sabre ground now.
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Post by John Greybeard on Dec 26, 2010 16:21:19 GMT
I think historically, as well as currently, most knife manufacturing is done with the edge of some kind of abrasive wheel, rather than the flat -- hence the "hollow" scooped out. The following excerpt is from Joe Talmadge of Knifeart.com (I don't know anything about Joe or Knifeart, but since it backs up my hypothesis, of course I'll throw them out there as authorities hahahahahaha)
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