The "Ask Nathan a Question" Thread

DocJekl said:
Nathan - my CPK EDC is in 4V which I know very little about, and I was wondering if you could tell me about your 4V steel properties vs your D3V offerings of which we know so much?



What steel is your EDC Shirogorov? I have some in Vanax 37, S90V, M390, Elmax, and Cromax PM, but wonder what you like the most.
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Nathan the Machinist Nathan the Machinist ?
 
#stillnotnathan luvs it when the real Nathan the Machinists nerds out. If you use the search feature with Nathan as the poster in this ANAQ thread, you will find a wealth of his posts on 4V and other alloys (spoiler alert: he doesn't like S30V!). As for his Shiro, what Shiro?! I know but I can't tell ya!

3/24/2017:

Nathan the Machinist said:
I don't think it's much of an issue of cost benefit ratio on high performance knives so much as finding an alloy and heat treat for that allow that maximizes performance for an application. There is a tendency to say: if some is good, more is better and want to jam as much carbon and alloy and vanadium into the steels and this can ruin them if overdone. It's like making a good soup, too many ingredients and too much salt ruins it. Look at S30V. 4% vanadium? 14% chrome? 1.45% carbon (that's a lot)? Hell, it's only 3/4 iron, it's no wonder it won't hold together in a knife edge. Then look at something like Infi: .3% vanadium, 8% chrome, .6% carbon. He didn't get that the level of performance by packing it full of ingredients, he chose the right alloy, made the right tweaks to it and optimized a heat treat for it. Other steels like 3V start adding some abrasion resistance to the mix at the expense of edge stability so they hold up longer in some applications but not others. Going beyond 3V you can get further gains in abrasion resistance but might start seeing actual edge retention go down due to stability problems in normal use. So finding the "ultimate steel" is always a fun quest but I don't think the answer will be some extreme alloy that's almost unmachinable.

Interesting true story:

A company my shop does work for was modifying a Kevlar fiber cutting machine design used processing jackets in the fiberoptics industry. The carbide blades were good for 10,000-15,000 cuts but were very expensive. I made blades out of D2 with the goal of saving money and we were hoping to see 4,000-6,000 cuts. With optimized D2, by the time we were done with it, we were getting 250,000 cuts from D2 blades. This is an example of the right alloy with the right heat treat outperforming a "super material" by a factor of 20. Finding the ultimate material for that application wasn't a matter of cost/benefit ratio, it was a matter of material selection, engineering and optimization. The fact that it cost less ended up being incidental.

We're working with CPM 4V right now. It has a pretty hard sweet spot and the large amount of well distributed fine carbides actually contribute to a higher compressive yield strength. That and the moderate chrome content help it achieve edge stability you wouldn't think possible on such a high alloy steel (It's about 85% iron) . At HRC 63-64 it will have longer edge retention than 3V in most applications. Surprisingly this includes rough use. We looked at the industry standard HT for it, variations of that and the HT provided by the best HT shop in the industry. We looked at tweaks we've applied to D2 and 3V. We've looked at a lot of stuff and have really done our homework. When we started we had a hard crumbly edge that wore well in cardboard but turned to dust in impact on knots in wood and other use that stress the edge. By the time we were done with it, a thin pattern (our 3" EDC) at HRC 64 can cut a 16D nail at 18 DPS with little damage. I'm not sure that a higher alloy and more difficult to machine material would outperform it.

So, all of that said, I don't think the answer to the "holy grail" is in more extreme alloys, I think it is in finding the right alloy and giving it the right treatment.
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11/14/2016:

Nathan the Machinist said:
All three steels have a combination of good abrasive wear resistance and toughness that lend themselves to good edge retention and durability in use.

3V has good wear resistance, corrosion resistance and high toughness, and with the Delta heat treat protocol it has good edge stability. It lends itself to something you're going to use hard and it's going to hold an edge well and never break. If I had one steel to choose for an all-around knife I had to rely on, Delta 3V would be my choice.

D2 has some of the best real world edge wear resistance but reduced edge stability, so it's a better candidate for someone cutting a lot of stuff like cardboard and leather. The CPM process ruins one its best attributes, which is a long wearing toothy edge from large carbides, so this is conventional D2 from Crucible. This was not a meaningful cost savings. It has good corrosion resistance and, though it is nowhere near as tough as 3V, it is tougher than most stainless steels that people are accustomed to and is more than tough enough for most people's needs. Most of the D2 knives that people have used are import material and tool-and-die heat treat. People that haven't used good D2 are in for a surprise. The best overall edge retention of any steel I've tested to date is an optimized D2, which is why I'm dusting it off. It's wonderful in a skinning knife and works well in the shop, job site, and woods.

4V is a wild card. It may stay sharper in rough use than other materials. It is the same chemistry as Vanadis 4, which is the material that supplanted CPM M4 as the world cutting champion steel. It will certainly have greater wear resistance than 3V, though probably not as good as D2 in actual use. It's expensive, it won't be very corrosion resistant, nor have a toothy edge and it may or may not develop good edge stability, <---- that is to be determined. But, we're pursuing it because we feel it may have a combination of edge stability and wear resistance that lends itself to thin high performance knives. Particularly at higher hardness. So, we think its performance potential may outweigh it's lower corrosion resistance in applications where we're trying to support a thinner geometry in rough use. I think the carbide content increases the compressive yield strength, reducing the tendency to buckle in thin sections found in an acute edge and in narrow primary grinds. It might be great in a racing knife. 👍
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Elgatodeacero said:
Jo the Machinist Jo the Machinist And Nathan the Machinist Nathan the Machinist

Would you please consider using some of this material for grips, or some similar stuff from G.L. Hansen?


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GCarta makes amazing micartas, but I don't think they would be up to Nathan's extremely high standards. Even if they were, the blocks are not very big and wouldn't lend themselves to a scaled production such as Nathan's, since the blocks are designed to be edge-cut, and are not a large sheet as would be ideal for a large mill.

Here's a little eye candy. My son and I have knives from the Golden Trout pattern, similar to what you linked, made within the past year:

Mine
img_5630-2-jpg.2234010


Son's
img_2632-jpg.2157319


A set I had made 3-4 years ago, in the Starry Night pattern
img_6279-jpg.1461793
 
DocJekl said:
Nathan - my CPK EDC is in 4V which I know very little about, and I was wondering if you could tell me about your 4V steel properties vs your D3V offerings of which we know so much?



What steel is your EDC Shirogorov? I have some in Vanax 37, S90V, M390, Elmax, and Cromax PM, but wonder what you like the most.
Click to expand...


4V has good edge stability for a high wear resistance steel and the sweet spot for it is pretty hard.

Delta 3V is already fairly abrasion resistant and relatively hard and has much better corrosion resistance, ease of sharpening, and is practically unbreakable.

I like 4V, and I will use it in race knives in the future, but I prefer Delta 3V for most applications, it has a better balance of properties.
 
twyych said:
I'm pretty sure the sheath is sold separately on that model.

ETA: Maybe Lorien Lorien can hook you up with one, but I'm not sure if he works with fruit leather.
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most of my experience with fruit leather consists of eating it, but I have an open mind. So open, in fact, that it might even be completely empty!
 
Nathan the Machinist said:
That's a good question. I think it should.
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I believe the subject was brought up after the first pre-order fried some power supplies so with the official announcement of pre-order #2, I was just curious if it gained any traction, thanks. I’m also wondering if I should add a line cutting notch into the sheath or saya for it, it could come in handy while fishing.
 
Jsega51 said:
Does the previous pre-order list hold any weight with the upcoming pre-order or is it another free-for-all? I was close last time!
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Nathan the Machinist said:
That's a good question. I think it should.
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What about those of us that officially said we’d be in when you were gauging interest to decide if you’d even make the run in the first place, and then didn’t make it into that crazy pre-order? (One week… 🤣) And have been begging for another ever since?

(Yes, talking about myself here.)

ETA - Here’s the interest poll thread. It is a VERY interesting read now in hindsight, given some of the “not in” responses, then some of those same folks ordered 2 in the pre-order! 😆:rolleyes:
 
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