Flat grind.. good or bad?

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Peteristico

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Nov 12, 2013
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Well I was about to buy an Ontario Ranger RD7 when I found this video:
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[video=youtube;SiVeNOpvYMs]http://www.youtube.com/watch?v=SiVeNOpvYMs[/video]
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I know, different knives, different steels, but both has flat grind blades. Cold steel replied:
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[video=youtube;vBnXhhfRwE8]http://www.youtube.com/watch?annotation_id=annotation_599531&feature=iv&src_vid=SiVeNOpvYMs&v=vBnXhhfRwE8[/video]
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According to Cold Steel's answer there was an issue with the heat treatment. But anyways the point still the same. Now I've my doubts on the flat grind blade structure for a survival knife. My question is, as title says, is flat grind recommended for outdoors activities? Or would you prefer a hollow grind blade?

Since I started thinking about this I looked for a similar knife but with hollow grind blade. And I found the Becker BK7. So, wich one would you choose? Ontario RD7 or Becker BK7?

Thanks! :)
 
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For two blades with the same thinkness at the spine, a hollow grind will be thinner near the edge than a flat grind, and, hence, less robust.

That said, the failure apparently shown in the video has nothing to do with grind and everything to due with a bad heat treatment. No grind would have prevented it.

If your priority is slicing and not sturdiness...like skinning....go hollow. Skinners are typically hollow ground. For more general purpose cutting....go full flat.
 
By the way, if you can get a Ranger RD7 to fail, get in touch with Justin Gingrich, the guy who designed it. I'm sure he would want to know how that posibly could have been done (I've seen him shoot them repeatedly with no effect).
 
Neither the Becker or the Ontario is hollow grind, they are sabergrind, which means you have more material in the blade.
This making it a little heavier, and also more solid.
They are also fulltang, the cold steel is called full tang, but construction is a little different.
I don't have the Ontario, but I've heard that the handle might need some work.
The Becker I have, fit and Finnish is perfect, shaving sharp out of the box, and a stand up company that produce blades that I would not hesitate to trust my life to...
 
The Ontario Rangers are full flat ground, not saber ground, unless they have recently changed design.

You are correct on the Beckers...they are also excellent knives.
 
That's right marcinek I spoke to fast, remembered as soon as I posted, haha
 
I don't see that failure as having anything to do with the grind. The initial blade deformation would have left that portion of the blade extremely weak.

When a knife is driven through a large piece of wood and a portion of that edge hits a knot, the change in grain pattern forces that part of the edge in a new direction while the rest of the edge retains its original direction. This lateral force tears off a chunk of the blade. The tell is the half-moon shape of the broken chunk.

Sure, a thicker, heavier piece of steel would have survived. In my part of the world we split wood with thick steel wedges. But knives are meant to cut, and the thicker the edge and blade, the worse it performs as a knife.

Battoning through heavy rounds with a knife is never a good idea. I heat with wood, and go through a lot of it. There are all kinds of things in wood -- bullets, wire, nails, rocks, knots and old, hardened branches. Grain patters can twist. It's not a good environment to be hammering a thin knife blade through.
 
I agree with Twindog - I would use a different tool for that job. But, if I had to use a knife for batoning, I would choose a saber grind, like a Sykco 711

from their website: The Leatherneck-SF (for Semper-Fi) has a saber ground clip point blade. It's hollow ground and honed by hand to a startling razor sharpness

It's not a good sign when a maker can't get their ad-copy straight (Since it's hollow-ground it ain't saber ground). That blade is designed more for stabbing than chopping, (for batoning, you normally don't want a swedge or clip point, again that's for stabbing).

The steel: German 4116 Stainless Steel: A fine grained, stainless steel produced by Germany’s ThyssenKrupp. Often used for medical devices and food processing, the steels Carbon and Chromium content give it a great degree of corrosion resistance, as well as strength and edge retention. 4116 Stainless Steel has a Carbon Content between 0.42-0.55 and it’s Chromium content is between 13.8-15.

Doesn't sound like a particularly tough steel - which is what you want - the Ranger uses 5160 - known for toughness - often used in choppers. I'd say the Ranger would get the job done for you, or the Becker BK7, in that price range.
 
As stated above the knife failed not due to grind, but either a poor heat treat, or it simply to much stress in a localized area.

Generally hollow grinds leave much less metal in the middle area of the blade, thus leave it weaker in that area.

Alot of people think that a convex grind is the best outdoor performer for wood processing and such. I only like a convex if it is so close to a flat grind you can barely tell. Those are some crazy performing knives when done properly.
 
the steel was obviously too brittle, the leatherneck is a robust blade! normal conditions I would have no fear of a breakage like that.
 
Flat grind is okay for opening boxes and skinning but if chopping or batoning wood you might wanna go with a different grind perhaps a scandi
 
jesse.smith said:
Flat grind is okay for opening boxes and skinning but if chopping or batoning wood you might wanna go with a different grind perhaps a scandi
Click to expand...

Why is that? Axes are pretty good for chopping wood, and I never see any scandi ground ones.
 
That is not true^ all of ESEE's knives are full flat ground... I dare you to try chopping with a junglas, and then tell me full flat ground blades can't chop. Scandi, or convex grinds also make good wood processing knives.
 
olybears57 said:
That is not true^ all of ESEE's knives are full flat ground... I dare you to try chopping with a junglas, and then tell me full flat ground blades can't chop. Scandi, or convex grinds also make good wood processing knives.
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The Candiru and 5 are not full flat ground. They are sabre ground.
 
Sabre is basically the same thing, the grind just ends slightly lower. My point is, flat ground blades can chop. Not that all of ESEE's knives are ffg
 
olybears57 said:
Sabre is basically the same thing, the grind just ends slightly lower. My point is, flat ground blades can chop. Not that all of ESEE's knives are ffg
Click to expand...

Full flat can, indeed, chop. But a full flat and a sabre grind are not basically the same thing. A blade has to be ground from edge to spine to be full ground. Now sabre and scandi ground...those are basically the same thing. The typical scandi is a zero flat ground sabre.
 
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