durability vs edge retention

JW Knives

JW Knives

Joined
Feb 22, 2011
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Speaking in very general terms and WITHOUT getting into the intricacies of heat treating, rockwell, steels, edge type, etc, do you believe that it is possible to create a blade that will chop through logs and branches and still be able to pop hair or slice news print?

I have been messing around with some of my production fixed blades and have found that being able to do both is a rarity. So rather than posting this in general I though I would put it here to see what you guys thought. Do you lean one way or the other (durability aka softer vs edge retention aka harder) ???

Jay
 
Yes, I can and do make knives that will do both. I also make knives that will do one or the other exceptionally well and the other not so well. You can't judge a blade by hardness alone. In my opinion you have to have the proper hardness and edge geometry for a given steel & intended application. For knives that may do both its a balancing act. For pure slicers its thinner and harder, for choppers its difinitely thicker but not necessarily softer. Just my .02. I'm anxious to see some other opinions.
 
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JW Knives said:
... do you believe that it is possible to create a blade that will chop through logs and branches and still be able to pop hair or slice news print?
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I like the fact that you chose examples of things knives are actually meant to cut :thumbup: If we get into stabbing car doors and chopping cinder blocks, it gets a little silly :D

It is absolutely possible, in fact it's not as difficult as some make it seem. And it's possible with a wide variety of steels, carbon, tool and stainless. As Darrin says, geometry plays a huge role. I also agree that a chopper should have a thicker, and possibly less-acute final edge, but doesn't have to be tempered back softer to be durable. A couple thousandths of an inch at the edge, and a couple more thousandths behind that, can make a big difference in a blade resisting chipping and rolling but still have a nice keen edge. Convex edges are great for this application.
 
It is definately achievable if you can get consistant with your methods and test your blades to zone in on that happy medium. For my bush blades, I need to find a compromise among hardness, edge geometry and blade thickness(for lateral strength)... yes, Mr.T... my tools are expected to see some prying on occasion... lol. Don't tell the other guys, K?

Rick
 
Rick Marchand said:
... yes, Mr.T... my tools are expected to see some prying on occasion... lol. Don't tell the other guys, K?
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That cat escaped his bag some time ago, bud ;) There's absolutely nothing wrong that. I myself have built a couple knives that were designed from the outset to withstand prying and digging, and yes, they will shave hair after splitting and chopping wood. They aren't as nimble as a fine skinner or filet knife, but they'd do in a pinch... whereas the reverse doesn't work out so well.
 
james terrio said:
That cat escaped his bag some time ago, bud ;) There's absolutely nothing wrong that. I myself have built a couple knives that were designed from the outset to withstand prying and digging, and yes, they will shave hair after splitting and chopping wood. They aren't as nimble as a fine skinner or filet knife, but they'd do in a pinch... whereas the reverse doesn't work out so well.
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Shhhh....... you had me at "digging". I like you 17% better than just before you posted that.:thumbup:
 
Rick Marchand said:
I like you 17% better than just before you posted that.:thumbup:
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Cool, I reckon I'm up to about 18% likeability now :D

Honestly though, Jay's question is a good one. Take note that he tested some production blades and they fell short. Production knives are, for the most part, designed to be easily-manufactured at minimal cost, NOT designed for truly superlative performance of more than one task. Thoughtful custom makers like Darrin and Rick have a lot more freedom to tweak geometry, materials and techniques.
 
I couldn't agree more with both of you. I wouldn't put out a "hard use" knife that i didn't expect would see at least some medium/heavy prying or digging... i've seen too many knives be used this way (many fail) not to at least expect it's going to happen whether or not i want it to.
 
rustyrazor said:
... I wouldn't put out a "hard use" knife that i didn't expect would see at least some medium/heavy prying or digging... i've seen too many knives be used this way (many fail) not to at least expect it's going to happen whether or not i want it to.
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Darn tootin'. There actually are some pretty dang good factory knives that stand above most. Our job as custom/handmade makers is to raise the bar and provide knives that perform even better.
 
Hold on guys, I don't think he said anything about chopping wood and shaving hair. He said chopping wood and popping hair.

(popping definition: floating the blade above your skin and catching hairs in their middle, lopping them off in the air in mid hair. See also: "tree topping" hair)

I think a lot of folks have never even handled a knife that sharp. And, in my opinion, you'll never see a knife that sharp chop wood and still tree top afterward without at least some kind of touch up.

It would take supreme fine edge stability. If anything would be up to that task, W2 would be a good candidate, but I don't think it is physically possible. (yes, that is a challenge you guys)
 
There appears to be different definitions of hair popping. I thought it was when the hair just jumps off your arm as the blade passes by, but the edge is touching the skin.

I have 3 Cold Steel machetes that will at least cut through a 4x4 and still shave my arm. One I reground went through a 3-4 inch branch 7 times, then split the pieces into quarters and would still shave. I did not try to cut newspaperbut I'm pretty sure it would. The edge geometry was heavily modified from the factory edge.
 
I think the major consensus of this thread reveals that YES, you can make a knife that'll do a reasonable amount gruntwork and retain a reasonable amount of sharpness. We are starting to argue semantics, here.

Rick
 
Really.... nobody comes through with something like "enough arguing - at this point we're really just splitting hairs" ?
 
Nathan the Machinist said:
Hold on guys, I don't think he said anything about chopping wood and shaving hair. He said chopping wood and popping hair.

(popping definition: floating the blade above your skin and catching hairs in their middle, lopping them off in the air in mid hair. See also: "tree topping" hair)

I think a lot of folks have never even handled a knife that sharp. And, in my opinion, you'll never see a knife that sharp chop wood and still tree top afterward without at least some kind of touch up.

It would take supreme fine edge stability. If anything would be up to that task, W2 would be a good candidate, but I don't think it is physically possible. (yes, that is a challenge you guys)
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... I've seen some so sharp you could dull them just by looking at them.


Good points Nathan... but don't rule out chopping 1/4 inch balsa. ;)

Or better yet,... rive out (split lengthwise) a perfect pair of cedar chopsticks and still tree top a hair?

I bet I could do maybe even 4 pair, but the stakes would be mighty high. :)

I'd probably go with Don's W2 and canola.
 
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Something like this. :)

DSCN2688.jpg
 
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