The "Ask Nathan a Question" Thread

ferider said:
#NotNathan, C., but the correct BF answer is that you need to buy another knife for this.

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That little doll looks minty fresh! 😍
 
SharpBits said:
How can I safely rough up my CPK handles? I want add a little more traction to my Basic 5.
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#notnathan that reminds me of when I was finishing a chopper with stall mat rubber handle. I had a can of Herculiner truck bed liner roll on, in case I needed better grip. Turned out I didn't need it, but I would do something like that before hacking into the scales.
 
bluemax_1 said:
It occurs to me, that collectors are a funny breed. You could probably list that for sale;
"Exclusive hard-use finish. This finish literally takes hundreds of hours to develop, over the course of years. It's not something we offer often, simply because of the sheer man-hours it takes. Priced to match. $15,000"


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I do appreciate that the CPK brand attracts all kinds, and for damned good reason. The collectors, the casuals, the "users", the actual users, the window shoppers, the flybys, and more. It's a testament, for sure.
 
SharpBits said:
How can I safely rough up my CPK handles? I want add a little more traction to my Basic 5.
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Look up silicone tape in the plumbing section of your hardware store.
Comes in a variety of colors.
I've used it a Lot on knives I've bought that came with small, uncomfortable handles. Adds a bunch of grip, And it's cheap too
 
This is a question for Nathan.
How long does heat treat hardness last? we presume that it lasts the life of the knife, but did someone checked that? what happens if you leave a knife outside in freezing winter temperatures over the winter months and check its hardness in the summer? or if you leave a knife outdoors in the summer at hot desert temperatures, does it lose its heat treat?
 
Plain Man said:
This is a question for Nathan.
How long does heat treat hardness last? we presume that it lasts the life of the knife, but did someone checked that? what happens if you leave a knife outside in freezing winter temperatures over the winter months and check its hardness in the summer? or if you leave a knife outdoors in the summer at hot desert temperatures, does it lose its heat treat?
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No, that's not how it works, it won't lose its heat treat in the summer heat. Although it certainly will in a campfire.

In a nutshell, the hardness of the steel comes from a structure called martensite which forms when carbon is able to get physically stuck between atoms of iron crystals at a high temperature (where the crystalline structure changes from body centered cubic to face-centered cubic and there's physically space for the carbon atoms to get stuck and trapped, it really is that simple) and they are locked in place when it's cooled down, straining the metallic bonds and hardening the structure. This hard structure is then tempered after quenching to relieve some of the strain and draw the steel back to a specific hardness.

There's a little more to it than that, but this is the general gist.

This is pretty much permanent unless you heat the steel above the tempering temperature, which will draw the hardness back farther.

There is something called retained austinite that can spontaneously convert over time, but a cryogenic treatment addresses the vast vast majority of any stabilized retained austinite and we do that.

My knives have been under -300°f as a part of their manufacturing process, any cold winter temperature you're going to subject it to will seem balmy in comparison.

The biggest danger is heating up the very leading apex of the edge when sharpening. The knife might not even seem hot, but if it is sharpened under powered equipment, you can draw the edge back, and that's the part that really matters.

But, assuming you don't burn your knife, the metallurgical structures that give it the characteristics that it has are, for all intents and purposes, permanent as long as you never overheat it. My tempering temperatures are in the 400s. Stay below that and it's fine.

It is an interesting question though. What happens to steel when it's 1,000 years old or a million years old?

There is a secondary hardening mechanism, precipitation hardening, and some materials can precipitate particles causing dislocations in the matrix creating strain hardening that way. For example aluminum gets harder and more brittle as it ages. Stronger too. Some titanium is this way. Lots of materials are like this. To a small degree, steel is also, although to a very small degree and this is very alloy dependent. The potential for spontaneous precipitation of some particle or conversion of retained austinite into something like bainite probably exists, but not to a meaningful degree in a human lifetime. But, thousands of years from now, I don't really know the answer to that.

Things like plastics break down naturally over the course of just decades, but they depend upon covalent bonds which are not readily reversible if they break. Metals hold together in a different way and, since those electrons are always moving around from place to place endlessly, those bonds, if broken, can just instantly reform. This makes metal much more long-lasting than anything dependent upon molecules. Fundamentally, there are no molecules in steel. In reality, there are some, the carbides, but iron is not fundamentally a molecular structure and does not have the limitations of one. Unless you get into intra granular corrosion and stuff like that, and there's them pesky molecules again.
 
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