Large fixed blades in 20CV

[JoviAl]

Can anyone shed any light on why Spyderco might have chosen to use 20CV in their Zoomer and Sustain models? I can get a fantastic deal on both models at the moment, and they would likely make excellent knives for work, but I am concerned about the relative fragility of 20CV compared to my more usual fixed blade fare of Elmax. Does the stock thickness mitigate any potential fragility or is it heat treated differently to thinner blade stock? I don’t pry with knives, but I do hack limbs off of trees when I don’t have an axe to hand.

Honest question, I’m not implying anything - I really am extremely tempted by one or both knives!

[vandelay]

Geometry matters more than alloy when it comes to strength. It's also possible they're doing something different with heat treatment to improve toughness too.
Larrin's tests also show 1095 performing pretty poorly, even at 57RC, but you can find tons of videos of people trying to break beefy knives like the BK2 and ESEE5 without much success.

Unless you're batonning with the knife, I don't think fragility should matter too much in a bushcraft knife.
It can matter for edge stability when cutting some hard materials or setting the edge to a very acute angle though, but the factory edges are probably fine.

[JoviAl]

Geometry matters more than alloy when it comes to strength. It's also possible they're doing something different with heat treatment to improve toughness too.
Larrin's tests also show 1095 performing pretty poorly, even at 57RC, but you can find tons of videos of people trying to break beefy knives like the BK2 and ESEE5 without much success.

Unless you're batonning with the knife, I don't think fragility should matter too much in a bushcraft knife.
It can matter for edge stability when cutting some hard materials or setting the edge to a very acute angle though, but the factory edges are probably fine.

I will be batoning with it, as well as all manner of other things woodland management related (including freeing pinch-stuck chainsaws from smaller logs if needs be). I can’t imagine they are flimsy by any measure, I was just wondering if there was/is a higher rationale for selecting 20CV as a steel for these larger fixed blades that are likely to take a bit of a battering in their intended purposes. I can’t imagine Spyderco just using it because they had some kicking about the shop - I would imagine it fulfilled their specific intended functions’s tolerances.

[Cl1ff]

I’ve seen videos of people battoning with the Zoomer.

I think spyderco used 20CV because it’s a good steel. For example, the Province was tested in s30v, which proved to be enough for the task, but went the extra mile with CPM-4V.

Spyderco seems to typically value wear resistance more than most knifemakers. I think this is reflected in their fixed blades and accompanying choices of steel.
20CV should handle the task, and especially so on a premium knife where the target users probably like a lot of wear resistance and corrosion resistance.

I think a similar logic can be applied to the Proficient in its carbon fiber and S90V.

I don’t think Spyderco’s bushcraft knife couldn’t handle bushcraft, though.

I have hacked stuff with 15V, REXT15, Spy27, 8Cr13MoV, VG-10, H1, and K390 Spyderco fixed blades. They’re all fine. I don’t often baton with most knives, so can’t say about that. However, the Zoomer is a more robust blade than any of those and I would feel most confident battoning it based on geometry alone.

Frankly, if the work is bushcraft, there’s little chance of a problem. If it’s “Bushcraft Plus”, including battoning overly difficult logs for entertainment, I would personally pick a cheaper knife.

[JoviAl]

I’ve seen videos of people battoning with the Zoomer.

I think spyderco used 20CV because it’s a good steel. For example, the Province was tested in s30v, which proved to be enough for the task, but went the extra mile with CPM-4V.

Spyderco seems to typically value wear resistance more than most knifemakers. I think this is reflected in their fixed blades and accompanying choices of steel.
20CV should handle the task, and especially so on a premium knife where the target users probably like a lot of wear resistance and corrosion resistance.

I think a similar logic can be applied to the Proficient in its carbon fiber and S90V.

I don’t think Spyderco’s bushcraft knife couldn’t handle bushcraft, though.

I have hacked stuff with 15V, REXT15, Spy27, 8Cr13MoV, VG-10, H1, and K390 Spyderco fixed blades. They’re all fine. I don’t often baton with most knives, so can’t say about that. However, the Zoomer is a more robust blade than any of those and I would feel most confident battoning it based on geometry alone.

Frankly, if the work is bushcraft, there’s little chance of a problem. If it’s “Bushcraft Plus”, including battoning overly difficult logs for entertainment, I would personally pick a cheaper knife.

I don’t abuse my knives willingly, but occasionally I do have to hack at stuff as my machete isn’t with me.

I’m sure 20CV is adequately strong enough for the design brief of two knives in question, I’m just wondering what drove the selection of 20CV over something else like 4V, Cru-wear, Elmax, etc. I’m genuinely interested rather than critical - was it driven by bar stock availability, cost vs performance, the perceived prestige of a top tier steel, etc

[aicolainen]

I can't answer your question as to why 20CV was chosen, but at a fantastic deal I figure that's a great opportunity to find out for yourself?

It does seem an odd choice, but I'm not qualified to know. Maybe the convex grind plays into the choice? Maybe it responds exceedingly well to a convex grind or maybe it yields better results in the machining process? Maybe the designer just prioritizes different characteristics than we normally see in bushcraft knives - I mean the Netherlands is surely not covered in "bush" suitable for crafting and the sheath certainly hints toward a person with very specific requirements and ideas. I simply don't know.

[JoviAl]

I can't answer your question as to why 20CV was chosen, but at a fantastic deal I figure that's a great opportunity to find out for yourself?

It does seem an odd choice, but I'm not qualified to know. Maybe the convex grind plays into the choice? Maybe it responds exceedingly well to a convex grind or maybe it yields better results in the machining process? Maybe the designer just prioritizes different characteristics than we normally see in bushcraft knives - I mean the Netherlands is surely not covered in "bush" suitable for crafting and the sheath certainly hints toward a person with very specific requirements and ideas. I simply don't know.

I’m just loath to splash $300 USD on a Zoomer or $330~ Singapore dollars on a Sustain when I’ve felt like I had to baby the 20CV on my folders due to a perception of relatively low toughness. I have some really fantastic larger custom fixed blades in Elmax, so I suppose I’m just a bit on the fence as to whether I really want drop a modest pile of cash on a large fixed blade when it’s made of 20CV and comes in a leather sheath (which tend to go mouldy every time I look away here in the tropics).

If it transpires that 20CV was chosen as it is less prone to chipping or fracture in larger stock thickness then I’d be willing to give it a go, but if it was chosen for its excellent edge retention and perceived exclusivity then I’ll pass - I don’t want to wreck a knife just through ignorance, and frivolous spending of money is increasingly hard to justify to myself in the current economic climate - I’d rather give the cash to someone in need than just buy another knife I don’t really need.

[aicolainen]

I’m just loath to splash $300 USD on a Zoomer or $330~ Singapore dollars on a Sustain when I’ve felt like I had to baby the 20CV on my folders due to a perception of relatively low toughness.

That's an absolutely reasonable position to take, and probably where most of us would come down.
On the other hand, some here wouldn't blink an eye to spend $300 in the name of science, just to find out how this steel performs in such a knife. Hence my suggestion :)

[yablanowitz]

Both the Zoomer and the Sustain are collaboration models (Ted Zoomer and Stuart Ackerman, respectively). I would wager a buck or two that the custom makers designing them had some input on the steel used. I don't think I would tell either of those gentlemen that they don't know what they are doing.

I have one of each of the knives in question. The Zoomer is quite robust, and I have used it quite a bit cutting hard woods (by which I mean woods like oak, pecan and locust grown in near-desert climates) without issue. I have not used it for a crowbar, star bit, piton or axe, so I can't say how well it will stand up to such use. The handle is heavy enough to make the blade feel quite light, not the balance I would look for in a knife I planned to chop with.

The Sustain has a longer but thinner blade and much smaller, lighter handle, pushing the balance more toward chopper, but I've never cut a thing with it, just admired it. I love the look of it, but the handle is just too small for my XXL hands, and the blade shape is more fighter than worker.

Frankly, I wouldn't call either of them a large knife, and from your description of your use case, I think I would look elsewhere.

[standy99]

Cpm 20cv steel equivalent
I can think of two plates of steel, the M390 from @Bohler and CTS-204P from @Carpanter, the three of the steels have a close chemical composition, and they offer the same properties (High edge retention, high corrosion resistance, high wear resistance, toughness, and hardness), and they fall in the same price range.

Have a Mule in 20cv and find it one of my favourite hard use steels. Never thought of it as being fragile

CPM 20CV VS M390
CPM 20CV ………………………………..M390
EDGE RETENTION 8/10 ………8/10
EASE OF SHARPNESS 5/10 ………5/10
CORROSION RESISTANCE 8/10….8/10
TOUGHNESS 6/10 ………………L 6/10

[JoviAl]

Cpm 20cv steel equivalent
I can think of two plates of steel, the M390 from @Bohler and CTS-204P from @Carpanter, the three of the steels have a close chemical composition, and they offer the same properties (High edge retention, high corrosion resistance, high wear resistance, toughness, and hardness), and they fall in the same price range.

Have a Mule in 20cv and find it one of my favourite hard use steels. Never thought of it as being fragile

CPM 20CV VS M390
CPM 20CV ………………………………..M390
EDGE RETENTION 8/10 ………8/10
EASE OF SHARPNESS 5/10 ………5/10
CORROSION RESISTANCE 8/10….8/10
TOUGHNESS 6/10 ………………L 6/10

Quite possibly I’ve been misremembering my toughness charts - I always thought it was way down compared to Magnacut, Elmax, 4V, cruwear and the like That would make a great deal of sense if it’s actually pretty tough stuff.

[JoviAl]

Both the Zoomer and the Sustain are collaboration models (Ted Zoomer and Stuart Ackerman, respectively). I would wager a buck or two that the custom makers designing them had some input on the steel used. I don't think I would tell either of those gentlemen that they don't know what they are doing.

I have one of each of the knives in question. The Zoomer is quite robust, and I have used it quite a bit cutting hard woods (by which I mean woods like oak, pecan and locust grown in near-desert climates) without issue. I have not used it for a crowbar, star bit, piton or axe, so I can't say how well it will stand up to such use. The handle is heavy enough to make the blade feel quite light, not the balance I would look for in a knife I planned to chop with.

The Sustain has a longer but thinner blade and much smaller, lighter handle, pushing the balance more toward chopper, but I've never cut a thing with it, just admired it. I love the look of it, but the handle is just too small for my XXL hands, and the blade shape is more fighter than worker.

Frankly, I wouldn't call either of them a large knife, and from your description of your use case, I think I would look elsewhere.

Thanks Yablanowitz, that’s top info The Sustain sang to me more than the Zoomer, but I had imagined it to be a weighty chopping/stabbing implement. If it’s not then it’s an easy pass - that kind of money opens up a smorgasbord of other options that I find very compelling or can go towards another custom.

[JoviAl]

I’m just loath to splash $300 USD on a Zoomer or $330~ Singapore dollars on a Sustain when I’ve felt like I had to baby the 20CV on my folders due to a perception of relatively low toughness.

That's an absolutely reasonable position to take, and probably where most of us would come down.
On the other hand, some here wouldn't blink an eye to spend $300 in the name of science, just to find out how this steel performs in such a knife. Hence my suggestion :)

It’s funny - I baulk at the prospect of spending $300 on a knife I might not LOVE but will still use plenty, but I think nothing of spending multiples of that on chainsaws or motorbike parts Each to their own

[endura3]

I wouldn't worry about the toughness of 20CV for the knives in question. One of my favorite small bushcraft knives is in 20CV and I've used it for years with no issues.

The toughness of Elmax and 20CV/M390 is pretty close too. I've never honestly noticed any difference between them in use, and for reference Larrin has the toughness of Elmax listed as 4.0 and 20CV 3.5, for only a half-point difference on his normalized 10 pt scale:

https://knifesteelnerds.com/2021/10/19/ ... esistance/

I think you'd likely be safe using 20CV for anything you'd be comfortable using Elmax for.

[Cl1ff]

Here’s the Sustain’s product description.
It describes everything you’d need to know about the knife. For example, it is 7.3 ounces.
It needs to meet the needs of some pig hunters and still be capable as an all around knife.

https://www.spyderco.com/catalog/detail ... Black/1019

20CV seems to be the high performance stainless steel of choice, but I couldn’t say why Elmax or something wasn’t chosen.
MagnaCut, Spy27, 20CV, S30V/S35VN/S45VN, S90V, and Elmax are all very good options in this range of well rounded stainless steels.
Any of these fulfill basically the same all around high performance purposes and would work for a wide variety of designs.
20CV, S30V, S45VN, and S90V seem to happen to be Taiwan’s stainless steels of choice for both fixed blades and pocket knives.
It’s definitely intriguing, but I think it makes sense.

This may be the case because it is potentially more efficient for Spyderco to acquire and ship USA made steel between Taiwan and them.

[yablanowitz]

Here are a couple of comparison pictures that might or might not help in considering the knives and not just the steel choice. Zoomer, Sustain, Respect and Darn Dao.

[jwbnyc]

Woof. Sweet collection.

[salimoneus]

I personally don't see 20CV as a tough enough steel for a hard use fixed blade application. Now as a kitchen knife or light use fixie it seems ideal, not really sure why it's not more popular for those specific applications, considering the incredibly high edge retention and corrosion resistance it has.