The "Ask Nathan a Question" Thread

Ghost coyote said:
I’ve been reading again on kitchen knives, and apparently geometry/blade shape is the king for that use, when you think about designing a kitchen knife, what do you visualize?
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I'm also highly interested in this. A chef's knife of some sort would be my first choice for the next CPK knife release. Some kind of mash up of a traditional western chef's knife/cleaver/camp chef.
 
steelcitysixteen said:
I'm also highly interested in this. A chef's knife of some sort would be my first choice for the next CPK knife release. Some kind of mash up of a traditional western chef's knife/cleaver/camp chef.
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Doesn't sound like the resulting tool would be a chef's knife...of course, I'm not much of a chef...so there's that.
 
gunslinger387 said:
Nathan, what is the sweet spot on your choppers that will deliver the most effective blow? For my personal application I’m curious about the BC, MC and K18. If it’s not too time consuming what makes it the sweet spot? Is it momentum, distribution of weight or something else entirely?

Thanks,

Kevin
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The center of percussion is about 6" back from the tip of the K18. That is where it will feel like a dead solid hit. But the sweet spot is 3" behind that, right in the center of the blade. That's because a hit behind the CP creates a rotation pushing the blade up into your hand which puts some of your own mass into the hit which is why the K18 can one-hit a 2X4 and is the most powerful blade I've ever experienced. That weighted pommel helps resist the rotational impulse. We had to use steel pins instead of aluminum because the aluminum pins holding the pommel were bending.
 
gunslinger387 said:
Nathan, what is the sweet spot on your choppers that will deliver the most effective blow? For my personal application I’m curious about the BC, MC and K18. If it’s not too time consuming what makes it the sweet spot? Is it momentum, distribution of weight or something else entirely?

Thanks,

Kevin
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Power cuts are the third of the blade closest to the handle and speed cuts are the third nearest the tip. For your 2x4, the angle you are hitting the board at is also important. You want to go at an angle and maintain a adequate scarf. You don't want to get trapped in the wedge of doom..
 
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Jo the Machinist said:
Power cuts are the third of the blade closest to the handle and speed cuts are the third nearest the tip. For your 2x4, angle you are hitting the board at is also important. You want to go at an angle and maintain a adequate scarf. You don't want to get trapped in the wedge of doom..
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One of Cliff Stamp's old videos had a very clear explanation of this.

Basically, when chopping wood, you NEVER want to chop at a 90 degree angle to the surface (grain). When you do that, a sharp edge may cut into the grain a bit, but as the blade behind the edge gets thicker, you're fighting against the friction AND compression of the wood grain (think of the blade as a wedge, driving into the wood, as the edge cuts the grain and the momentum attempts to drive the blade deeper, the thickening blade is attempting to force the cut apart, AGAINST the compressive strength of the wood).

If you cut/chop at an angle, the wedge shape of the blade winds up prying the wood upwards. It actually has a direction to move, with less resistance/strength. That's how you pop wood chips out of the cut. As the wood above the angled cut pops upwards, it decreases the resistance, allowing the edge and blade to bite deeper.

Other part of the equation is the V-notch. You want to make alternating cuts to make a V-shape. How far apart the top of the V-notch will be, is generally dictated by the thickness of the wood you're chopping. A thicker piece of wood requires the first cuts (top of the 'V') to be farther apart, so the bottom of the V doesn't end before you're through the wood.

I always found it hilarious watching 'knife/blade reviewers' on YT, hammering straight down (90 degrees) at the same spot/notch (making hardly any progress) while commenting on the blade's 'performance'. Huh. I wouldn't trust a sportscar reviewer's assessment of 'performance' if they can't shift out of 1st gear either.

P.S.

Shouldn't need to be stated, but I didn't bother posting this for Jo's benefit (she sure as heck doesn't need it), but for anyone who might not have understood what she was talking about (or seen Cliff's video).
 
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Jo the Machinist said:
Power cuts are the third of the blade closest to the handle and speed cuts are the third nearest the tip. For your 2x4, angle you are hitting the board at is also important. You want to go at an angle and maintain a adequate scarf. You don't want to get trapped in the wedge of doom..
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Is that pretty much the same for everyone, or will it be different for people who are taller, or have longer arms, or giant feet, etc.?
 
Any chance you could do a pre-order for a few new scale runs for old models? For example, allow us to pre-order HDFK, FK, and Chopper scales in materials such as Double Black, Double Red, and ECAM assuming there is enough interest in the pre-order to justify a run? And even if the pre-order total is a few short of the minimum run, having a few extra on hand probably wouldn't hurt. I'm sure people would scoop them up over time as knives change hands and peoples scale preferences change.

I'd seriously order a dozen scales (4 each of Double Red, Double Black, and ECAM) for the HDFK. Ask Jo how many scales I've bought for the SDFK if you don't believe me! 🤣
 
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unwisefool said:
Is that pretty much the same for everyone, or will it be different for people who are taller, or have longer arms, or giant feet, etc.?
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The part of the knife and the technique are the same, but employing the technique can look a lot different depending on your physical characteristics. I am short and small, but good technique lets me be competitive. I don't have to squat like some of the big folks which cam be nice, but it also limits the inertia (for lack of a better word) I can get behind my cut. I am cutting at chest height while a lot of the guys are cutting closer to the waist. The cutting bench heights are standardized and the same for men and women.
 
Jo the Machinist said:
The part of the knife and the technique are the same, but employing the technique can look a lot different depending on your physical characteristics. I am short and small, but good technique lets me be competitive. I don't have to squat like some of the big folks which cam be nice, but it also limits the inertia (for lack of a better word) I can get behind my cut. I am cutting at chest height while a lot of the guys are cutting closer to the waist. The cutting bench heights are standardized and the same for men and women.
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Are you allowed to wear shoes with higher heels or with thick soles to give you a slight boost? Or would that be against the rules/not necessary?
 
Jo the Machinist said:
As long as they are closed toe and rubber bottom it would probably be OK, but since I am not used to shoes like that, it would probably be detrimental
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Makes sense. My wife is pretty short, so she started wearing shoes and boots that give her about an inch boost and to her it makes all the difference. Buuut she's also not running around with a large knife chopping things like a ninja, so there is that.
 
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