The "Ask Nathan a Question" Thread

Sagandavis said:
Is there a pic of the IP micarta you described in yesterday’s sale? Trying to decide what to put on mine. Didn’t see it in the encyclopedia. Thanks! And sorry if this should be posted elsewhere
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There are a lot of good pictures recently posted on the basic five field knife thread
 
Nathan the Machinist said:
I don't really know the answer to this one

I could do a pre-order for the EDC or the 10-inch chopper right now, but I'm getting pretty late delivering the Shivs so I don't think I should start a new pre-order until that one is done.
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Since I've already gotten my SHIV 2.0 !... I'm all for a 10 inch chopper pre-order !!!...so I hope the chopper is the next one up since we haven't seen
A chopper pre-order for some years now but we just had a run of the DEK Series, The SHIV 2.0, The K-18 and the K-20 swords, the basic 5,the UF2,the kephart and if im right the last chopper pre-order was like 5 years ago in 2019 !...
So imo that's a long time to go without a good chopper being made for sale!...

Frank Cervantes AKA NMFrank87
 
NmFrank87 said:
Since I've already gotten my SHIV 2.0 !... I'm all for a 10 inch chopper pre-order !!!...so I hope the chopper is the next one up since we haven't seen
A chopper pre-order for some years now but we just had a run of the DEK Series, The SHIV 2.0, The K-18 and the K-20 swords, the basic 5,the UF2,the kephart and if im right the last chopper pre-order was like 5 years ago in 2019 !...
So imo that's a long time to go without a good chopper being made for sale!...

Frank Cervantes AKA NMFrank87
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I feel the same as Owen Wilson in Starsky and Hutch in the below video link, except with CPK lol

Choppers would be nice, but I’ll take anything
 
Tools_and_Tights said:
I’ve noticed that some companies run their CPM 3V at 57-59 HRC. Can anyone explain the benefits of running a scandi ground knife in CPM 3v with the lower 57-59 HRC rather than 60-61 HRC?

Thank you for your time!
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Good lord that's not optimal.

A scandi is typically between 11 and 13° DPS. Fine edge stability is critical here.

Also, due to its high abrasion resistance, even at that lower hardness, it's going to be a bear to sharpen with that much bevel in contact.

It is not an optimal alloy for a scandi. But at low hardness? And probably using the secondary hardening hump? That sounds like a real mess to me. I would never do that. What purpose does it serve?
 
Nathan the Machinist said:
Good lord that's not optimal.

A scandi is typically between 11 and 13° DPS. Fine edge stability is critical here.

Also, due to its high abrasion resistance, even at that lower hardness, it's going to be a bear to sharpen with that much bevel in contact.

It is not an optimal alloy for a scandi. But at low hardness? And probably using the secondary hardening hump? That sounds like a real mess to me. I would never do that. What purpose does it serve?
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Marketing to the… uninformed.

There are plenty of people who simply go for whatever super steel is currently in vogue, without any consideration to either usage, or heat treat.

Plenty of knife manufacturers jumped on the 3V train.

Same goes for Magnacut, when word spread about the new super steel, and as you’ve already mentioned, companies have somehow managed to produce crap examples of Magnacut, despite Larrin publishing the heat treat he came up with in development.
 
bluemax_1 said:
Marketing to the… uninformed.

There are plenty of people who simply go for whatever super steel is currently in vogue, without any consideration to either usage, or heat treat.

Plenty of knife manufacturers jumped on the 3V train.

Same goes for Magnacut, when word spread about the new super steel, and as you’ve already mentioned, companies have somehow managed to produce crap examples of Magnacut, despite Larrin publishing the heat treat he came up with in development.
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They can follow the heat treat to the letter. But that doesn't stop them from burning it in their manufacturing process...
 
Nathan the Machinist said:
Good lord that's not optimal.

A scandi is typically between 11 and 13° DPS. Fine edge stability is critical here.

Also, due to its high abrasion resistance, even at that lower hardness, it's going to be a bear to sharpen with that much bevel in contact.

It is not an optimal alloy for a scandi. But at low hardness? And probably using the secondary hardening hump? That sounds like a real mess to me. I would never do that. What purpose does it serve?
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I have no idea. It’s a little confusing, which is why I decided to make a post asking about it. I called their customer support and also asked about what their Magnacut is being heat treated to and the lady I spoke to said that the Magnacut is also being heat treated to 57-59 hrc.

So being optimistic, do you think it may be run lower to increase toughness?

I think it would be awesome if you made a YouTube series talking about the Who, What’s, When’s, Where’s, and Why’s of various steels! There’s way too many videos online that provide great marketing, but poor discussion of legitimate information regarding knives.

I’ve watched your long video discussing the Delta 3v protocol probably a few too many times but really enjoyed it, but I’m sure it’ll end up making the Fridays sales even more competitive…..sorry everyone 😅
 
Increasing toughness usually comes at the expense of durability

You're unlikely to break one of these knives at an optimal hardness. It's ridiculous to run those materials that soft because then they're fragile and weak. No, they probably will never break at that hardness, but they're not going to break at a optimal hardness either. But what they're going to do is suck as a knife. They'll hold a mediocre edge and, despite being soft, they're still going to be a bear to sharpen.

This is because edge loss is rarely due to abrasive wear. Especially at that angle.
 
XtianAus said:
Hey Nathan can you explain the difference?What do you mean by this? Toughness being the ability to break a knife and durability, the strength of the edge?
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I, and most people, would define durability as the ability to withstand use, and rough use, without taking damage. A very durable knife, like I try to build, can tolerate extremely rough use without accumulating damage or much edge loss. There are two aspects that are important here. First of all, strength needs to be high, which is associated with higher hardnesses. So number one, you need to have high hardness while maintaining high ductility. The second thing is the ability of an edge to shrug off rough use. There are aspects of a microstructure that are very important in the small and narrow geometries of a knife edge that are not found in many other applications of hardened steel such as tool and die. For example, things like areas of stabilized retained austinite can actually make a stamping tool tougher, while also reducing dimensional growth from heat treat. But, in the narrow sections of a knife edge, it acts like the perforations in an old postage stamp. The same is true with carbon lean martensite and precipitated secondary carbides found in high tempers using the secondary hardening hump that work great in a stamping tool but are suboptimal in a knife edge. But very very common.

Toughness is the amount of energy absorbed in an impact fracture. The test will take a sample, frequently with a C or V notch, and swing a pendulum through it. Measuring how far the pendulum carries after the break, where you can measure the amount of energy absorbed by the fracture. That is toughness. Unhardened mild steel is quite tough. And a knife made of this material, the edge would fold in light use. This is a good example of high toughness and low durability, a dead soft knife.

Knives that are tempered soft to increase toughness are unnecessary and counterproductive with modern alloys and heat treat.

There can be compromises to the integrity of the knife for ease of manufacturing. At the end of the day, you can make more knives if they're soft and high tempered because it grinds faster.

But the takeaway here is, toughness and durability are not remotely the same thing. Often one comes at the expense of the other. Also, wear resistance is not edge retention. Edge retention is edge retention. Wear resistance is but one component of edge retention. Abrasive wear is frequently not a primary mechanism of edge loss. Edge stability is key, and comes from a strong yet ductile microstructure associated with high hardness and a clean uniform fine-grained matrix with fine evenly dispersed carbides.

Low hardness helps prevent crack propagation, but addressing the root cause of crack propagation is a better way to prevent chipping and breaking.

Good knives are hard. And hard knives are good.
 
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