Argument against flat grinds

Londinium Armoury said:
Zero
https://imgur.com/a/cQYrZfS
Natlek you don't need to remove anything from the spine, just blend up to its level.
Here is diagram without your excessive matetial removal of the spine.
Click to expand...
We both had the same confusion. But in the end it is bark river that confused the issue. The blades are not and cannot be convex profile as designed. They are flat ground transitioned to a convex edge that is blended to the flat. Just a larger convex. Others do this as well.
 
Natlek said:
In my book that is Axe..............
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axe profiles vary by brand like knives. I have seen some that fit and many that don't. All we are talking about is how big a convex bevel you will have. Is it small at just the edge, or is it 1/3 the way up the side of the blade or is it the entire profile.
 
Cobalt said:
That's what it seems like is being done by bark. However, that is not a true convex blade profile. That's just convex near the edge blended into a modified flat grind.
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To claim it "isn't a true convex", you would need to define a true convex, mine meets the mathematical definition.
A flat grind is well defined, it is flat and at a certain angle.
A hollow grind has a specified radius and is also well defined.
We know what is meant by a convex grind, but the curvature is not constant and so many different profiles are still technically convex.
Another issue is that design and execution are separate things. I execute my convex starting with some flat grinding, but that is just to get me there.
Some makers hollow grind with a small radius wheel and walk it up. The result is a hollow grind, but without a well defined constant radius.
 
Richard338 said:
To claim it "isn't a true convex", you would need to define a true convex, mine meets the mathematical definition.
A flat grind is well defined, it is flat and at a certain angle.
A hollow grind has a specified radius and is also well defined.
We know what is meant by a convex grind, but the curvature is not constant and so many different profiles are still technically convex.
Another issue is that design and execution are separate things. I execute my convex starting with some flat grinding, but that is just to get me there.
Some makers hollow grind with a small radius wheel and walk it up. The result is a hollow grind, but without a well defined constant radius.
Click to expand...

Curvature does not have to be constant, but it needs to be there. This is where the difference is. If you are blending a thick flat grind into a convex, there will be a curve that transitions into a flat. That's not a convex grind, and that is what it appears Brk is doing.
 
Natlek said:
@ Mike Snody make knives like that one.
I should have expressed myself better......double hollow grind bevels with same height of grind like chisel one would be weaker, most likely unusable .
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Snody still uses a back bevel on his chisel ground knives.

Full height hollow ground knives exist and, I can assure you, they are far from unusable.
 
Cobalt said:
Curvature does not have to be constant, but it needs to be there. This is where the difference is. If you are blending a thick flat grind into a convex, there will be a curve that transitions into a flat. That's not a convex grind, and that is what it appears Brk is doing.
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Agreed. I walk it all the way up and don't leave any flat. In the end you can't tell that I started with a portion of flat. I can only speak for mine, I don't know what the Brk looks like.
 
scagel knives were nicely done full convex grinds. Fallkniven does plenty of convex grinding, or at least Seki does it for them, lol.
 
Spears said:
Snody still uses a back bevel on his chisel ground knives.

Full height hollow ground knives exist and, I can assure you, they are far from unusable.
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Without sharpening back side blade will steer , disadvantage is that they are hand specific .......left or right
Of course they exist .But with same spine thickness and width as chisel grind on same Dia. wheel ,I m afraid it would be more thin then chisel .That s why I say thinner then full flat and thicker then double hollow
 
Londinium Armoury said:
Zero
https://imgur.com/a/cQYrZfS
Natlek you don't need to remove anything from the spine, just blend up to its level.
Here is diagram without your excessive matetial removal of the spine.
Click to expand...
I get it , finally ! Your words ....It would not be an absolute straight V under a microscope up against a engineered flat surface, it would be blended as though it looks V to the naked eye at a glance..
 
Fir Na Tine said:
Are we talking blade geometry or edge geometry? My experience is convex edge geometry is stronger than a V edge. V and convex edge will perform different and that could be good or bad depending on media. A saber grind blade geometry will batton wood better than a FFG due to better splitting wedge shape. FFG is better at slicing through media with less resistance when the media is wider than blade width IE cardboard
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I can't tell the difference.
 
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