Flat Grind or Hollow Grind Folders

[Confederate]

While perusing eBay last week I found two Spyderco Endura 4s (black with partial serrations) for $35 each, new. I have a green Endura 4 flat grind, which is a great knife, but I actually prefer the hollow grind on my black Endura as it gives me a decent spine. Both knives got here yesterday and I couldn't believe I got them for that price, (including shipping).

I can appreciate the fine edges of a flat grind knife, but I also really like the extra strength of a decent hollow grind knife. Case in point, not only the Enduras, but the Cold Steel Voyagers. I have both the clip point (Bowie) blade and the Vaquero, and am mystified why no one seems to like the Vaquero much. I also picked up the tanto blade model (all XLG) and note that it has an enormous spine (and a couple of extra ounces, to boot). Still, it's clearly a much stronger knife. The spine gives it substantial chopping ability, which is totally lacking in the other two flat grind blades. But would I actually carry it?

No, not really. Not unless I was expecting emergency situations where I needed to pry or baton, which, frankly, doesn't happen very often. It made me wonder why Andrew Demko or Lynn Thompson packed so much steel into the blade. Also, would anyone want a flat grind tanto? I don't know. I would have appreciated a little more steel on top, but in this case I think Demko and Lynn Thompson went a little overboard.

What are the actual advantages of flat grind knives, anyway? Don't they end up weakening the blades in some cases? Nutnfancy wants to baton his flat grind clip point Voyager and he's already whacked on a hollow grind tanto Recon 1 (no failures). Still, I like the tanto version and wondered how many of you guys are packing an XLG tanto despite the weight? If not, how about the Vaquero? (I see self defense advantages with the Vaquero over the Bowie, but many prefer the Bowie.)

Thanks!

The CS Hold-Out (top) and Vaquero Voyager, both great knives with flat grind blades.

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[GatorFlash1]

Flat grind has lower drag at the same angle as hollow grind because it doesn't have the step in the blade a hollow ground knife has. That being said, many hollow ground knives seem to be thinner down near the edge which makes them cut very well. But, given the same steel, thickness, etc. the flat grind should have lower drag (less friction) and cut better. Don't split hairs with this as most of the time you couldn't tell the difference in actual use.

http://zknives.com/knives/articles/knifesteelfaq.shtml

 

[Dorito Monk]

Given the choice between the two, I'd go with the Flat Grind every time.

I find that full flat grinds have a few advantages, namely:
- They're extremely easy to convert to convex-grinds, or to change the edge angle without worrying about rubbing that shoulder on hollow-ground knives.
- They slice better, without mangling the material (ex: try slicing an apple with a Para 2 - it will work fine, no matter how thin you want to slice it. Try it with a Manix 2, and you'll probably just mangle your apple. There's a reason most high-end kitchen knives are flat ground.)
- They look nice! I just prefer the looks of flat ground blades.

Also, I don't really find hollow-ground blades to have any advantages. Some folks tout the strength of hollow-ground knives, but I've never found the grind to make any significant difference in the strength of a knife. That isn't to say that I won't have anything to do with hollow-grinds; they're perfectly serviceable, just not my preference. These are just things I've found from using FFG / Hollow ground knives.

 

[Confederate]

It seems to be the way things are going nowadays. But you guys are right about hollow grind knives cutting awfully well. The Voyager XLG Tanto goes from a thick and heavy spine to a surprisingly thin taper to the edge. It's not so tapered that it will break, but it does rival the fine edges in flat grind knives, though slicing food items like tomatoes can be problematic. But that's not what they're made for. A flat grind knife can shave thin slices of a tomato, whereas the Voyager Tanto XLG might be better suited for quartering the fruit.

But if I were a LEO and found myself having to force a closed door to open, the flat grind might work, but the thick spine of the Tanto would certainly be superior.

Looking at my Enduras, both could slice fine strips of tomato with no problem, but I really would prefer the hollow grind. The only difference I can see looking at the flat grind and the black hollow grind, the only difference is that the edges sweep up to a thicker spine. But the sweep looks awfully similar. If one could easily remove steel on the blade of the black knife, I dare say the spine could be blended in to the blade and it would come close to being a flat grind. In other words, I don't see a lot of difference between the slicing ability; however, the hollow grind does seem to have some extra heft. In the CS Voyagers, I prefer the flat grind; but in the Spyderco Endura, I think I like the hollow grind best. But there doesn't seem to be a very significant difference. In other words, I wouldn't run out and buy a flat grind Endura if I had a hollow grind. As for looks, I think flat grinds may be a passing fancy. Eventually people may want just a little more strength in a more substantial spine. Just my two cents.

But...ummm...on the other hand, I may run out and buy the knife in different colors. The FRN array of rainbow colors is very tempting for collectors.

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[Robs92XJ]

You seem to like saber grinds more than full grinds, is what it sounds like to me. Almost all hollow grinds I've seen have a flat (full thickness) portion near the spine, so they are technically a type of saber grind. You could make a full hollow grind, and it would end up looking like a straight razor's grind and would leave the edge rather weak, and be even lighter than a full flat grind. You could also make a saber grind with flat or convex bevels that would give you extra heft.

I'm not the biggest fan of hollow grinds. As I see it they have two real advantages, one is that the portion of the blade immediately behind the edge bevel is thinner than on a comparable flat grind, so it has better penetration, initially. For cutting thin materials (say paracord), it might outperform the flat grind. The other advantage is related to this, which is that repeated sharpening will not cause the edge to get thicker, at least not to the degree it would with a flat grind. That's because the blade does not get thicker for a few mm behind the edge.

On the downside, the relatively sudden increase in thickness at the top of the hollow causes binding in thicker rigid materials like wood. Also the edge will be somewhat weaker for a given edge thickness than it would in a flat grind. However many hollow grinds are very subtle, hardly concave at all, so they are often little different than a flat grind.

 

[Confederate]

You're right if the edge is too thin. Saber grinds have very consistent, strong edges. In the Voyager series, the thick spine yields to a sharp but strong edge. But it's too heavy for me to carry regularly. I can take it by the end of the grip, though, and can actually chop wood. What was Lynn Thompson thinking when he allowed it to be designed that way. I like the tanto design and still carry my Gunsite 5-inch, which cuts like a champ. It's gorgeous, too. The new Vaquero and Bowie blades have been widely praised for their strength and they're good defense knives, but big. I think the older knives are better from the standpoint that they were strong enough, and yeah, I do like a spine on my knives. The CS knives were also beautiful because they were polished.

The flat grind knives are probably strong enough, too, and the new Enduras, Hold-Outs, Voyagers, Recon 1s and others will probably be fine. But I also like the hollow grinds because they have thinner edges and sturdier spines. But I like the saber grinds too because they're sharp enough and tend to be strong. I do like the edge to taper down pretty quickly though.

We'll see.

 

[Buffalohump]

There are always issues with blade strength. I think this problem is overstated. If you dont pry with the knife, you should never have a problem. A flat grind is a more efficient cutting grind, end of story.

With customs its also a more difficult grind to achieve. Hence most customs are hollow ground.

 

[Confederate]

It's more efficient, granted. But people use their knives for many things other than cutting. I've never batoned a knife in my life, but some people want to do that...and we've seen them club a good knife into powder doing it. And now they're doing it with folders.

Although I concede flat grinds are more efficient, I reckon I'll always prefer a good hollow grind because that's just what I'm used to. Flat grinds are clearly the coming fashion design and if they take in popularity, then I may change my views! Until then, I'll prefer a bit of a spine to my knives and the blade shapes of a good hollow grind! As far as edges go, if the new flat grind designs can eliminate the accursed chisel grind edges in some of the knives I'd otherwise like, great!

My CRKT S-2 has a great blade in my view.

This Alaskan Buck also is blade I like.

My little Bear Damascus has a nice flat grind.

If flat grinds will eliminate abominations like the chisel grind edges, which make cutting
difficult for right handers, then great...bring them on!