420HC - Thoughts?

[buckman110]

Case has already confirmed their Tru-Sharp is 420HC, when they've actually been asked; at least a couple or three members have recently asked, and posted about it on the forum. Their 'CV' steel might be a little more of a mystery (to us), though it seems very comparable to decent 1085/95-grade steels in how it sharpens up and holds it's edges.

My take on 1095 being 'better than' 420HC (or not) is less about the steel type, and almost entirely about the maker's skill at getting the most out of it. 1095 has more built-in potential to be better, by virtue of it's higher carbon content, which is sometimes nearly double that of some examples of 420HC (1095 @ 0.9-1.0% carbon, 420HC @ 0.5-0.6% carbon). Carbon is what makes steel hardenable by heat treat, and the upper limit of it's RC hardness will be determined first by the carbon content, and secondarily by what the maker does with that in heat treat, if they take advantage of it. The most obvious example to me, of how this is important, is with Schrade USA's older 1095 blades, which were hardened to near-60 RC levels, and those edges will definitely hold up longer than any 420HC edge. This level of RC hardness isn't possible with any version of 420HC I've ever seen. This isn't to say 420HC isn't perfectly adequate for 99% of the tasks expected of traditional knives; but if one is looking for something a little better, then 1095 from a quality maker could definitely be worth paying a little more for. As with any steel, there are some horrid examples of 1095 out there too, from different manufacturers (I have at least a few like this, which won't take nearly as fine an edge, and won't hold it either).

1095 is also minimally complicated with any other alloying elements (chromium, etc), which should make it easier to keep grain size as fine and uniform as possible, assuming the manufacturing is relatively clean and free of impurities. Again, this depends on who actually makes the raw steel in the first place; the same is true for 420HC and other non-proprietary steel formulas.


David

Not true on the Rockwell on 420hc Paul bos heat treats his to 58-59. And blows schrades old 1095 outta the water. 56 ish hardness on the schrade. Great steel don't get me wrong. But bucks 420hc is the best 420hc available today in my opinion.

 

[pjackst]

Can anyone tell me if my recent garage sale Russell Green River 9" carver is likely 420HC? There's nary a blade I'd turn down for 50 cents- I picked it up to trim down the length and create an outdoor utility kind of thing, retaining the trimmed off section to make a whole new lil something as well. I'd given it the 10 min my attention span could spend in google searches as to the blade steel, and I think I came up w 420HC. Maybe one of you handsome devils can help me out...

 

[pjackst]

anddddd I am, only in this late hour, seeing that this thread has about 6 pages of responses, none of which I have read before posting... shame on me!

 

[Obsessed with Edges]

Not true on the Rockwell on 420hc Paul bos heat treats his to 58-59. And blows schrades old 1095 outta the water. 56 ish hardness on the schrade. Great steel don't get me wrong. But bucks 420hc is the best 420hc available today in my opinion.

I'm aware of Buck's 420HC hardness spec to 58 (never seen it spec'd by Buck at 59 though; see below). Some of their upgraded steels are spec'd a bit higher (ATS-34, 13C26, S30V), but not the 420HC. Buck has gotten the most out of their 420HC, more than what the original maker of the steel designed for it (Latrobe spec'd it to mid-50s RC); nothing in my post implies otherwise. But the Schrade USA 1095 @ 60 still holds edges better at similar geometry (RC scale is non-linear, so it's significant). The blades on my Schrade 8OT are very thin, but have better resisted the edge-rolling that is still evident on similarly thin-edged Bucks of mine. I even have older Case blades in carbon steel (predecessor to their CV, as named), that've also held up better with similar geometry; that's where the impact of the carbon content makes the bigger difference, so long as the heat treat is at least decent. At higher hardness, the edges on the 420HC Bucks still damage more easily, but the thinner fragments tend to break away, rather than just fold or dent as 420HC does at somewhat lower RC.

(quoted from: http://www.buckknives.com/custom-knife/customizable-110-folding-hunter/CKS110/ )

"420HC STEEL
This is Buck's standard blade material because it approaches the wear resistance of high carbon alloys while delivering the corrosion resistance of chromium stainless steels. Add our exclusive heat-treat process and you have a very user-friendly combination of superior corrosion resistance with excellent strength for wear resistance and durability. You also have a blade that is easy to resharpen. For best performance we harden to a Rockwell hardness of Rc 58."

David

 

[pinnah]

Not true on the Rockwell on 420hc Paul bos heat treats his to 58-59. And blows schrades old 1095 outta the water. 56 ish hardness on the schrade. Great steel don't get me wrong. But bucks 420hc is the best 420hc available today in my opinion.

My sense is that no one statement can be made about Schrade USA that is consistent other than they weren't consistent!!!

Some of my old Schrades and Schrade-Waldens are very hard. I've heard some folks complain that Schrade made Ulsters were soft but I've not noticed it compared to my Opinel Carbones which I totally believe are 56 Rc. One thing to remember is that Schrade was sort of an umbrella that spanned a ton of different plants and it well could be that you and OWE are both right.

I know my 5OTs are pretty darn hard and my older H-15 is very, very, very, almost chippy hard.

 

[Aias]

I only have experience with Buck's version of 420hc--it works fine, especially on food. I don't dislike it, but I nearly always reach for something else, typically GEC's 1095. Derrick, if you had another run of those English Jacks in 1095, I'd very likely get one... with some deeply jigged bone. Just sayin...

 

[buckman110]

Never seen a schrade carbon that hard. There stainless yes indeed. Its great.

 

[Obsessed with Edges]

My sense is that no one statement can be made about Schrade USA that is consistent other than they weren't consistent!!!

Some of my old Schrades and Schrade-Waldens are very hard. I've heard some folks complain that Schrade made Ulsters were soft but I've not noticed it compared to my Opinel Carbones which I totally believe are 56 Rc. One thing to remember is that Schrade was sort of an umbrella that spanned a ton of different plants and it well could be that you and OWE are both right.

I know my 5OTs are pretty darn hard and my older H-15 is very, very, very, almost chippy hard.

On that note, here's an old Schrade promotional flyer/catalog page detailing the steels they'd used, and the hardness specs for each. Seems to some extent, I'd even underestimated some of their 1095 blades, which are listed at HRC 57-62. Could've been some variability in their blades over the years; the 'good ones' are very easy to spot though.


David

 

[buckman110]

I can whip up a old timer in nothing flat. It may state that. But never used, seen, or sharpened any carbon steel that hard. Now bucks old 440c at times can be challenging. But that old 1095 I really like in say the bk-2. It all has a purpose place and use. And it's a matter of choice.

 

[Obsessed with Edges]

I can whip up a old timer in nothing flat. It may state that. But never used, seen, or sharpened any carbon steel that hard. Now bucks old 440c at times can be challenging. But that old 1095 I really like in say the bk-2. It all has a purpose place and use. And it's a matter of choice.

Ease of sharpening the steel is essentially independent of the rated hardness of it; makes a small difference, but almost negligible. With a simple low-alloy steel like 1095, it has no hard carbides, which are what make steels like 440C more challenging (440C has heavy chromium carbide content). This has nothing to do with RC hardness, as the abrasion resistance (difficulty of sharpening) is related to the chromium- or vanadium-carbide content, and not the blade's RC hardness spec, which reflects the hardness of the steel matrix (independent of the carbides). This is part of the beauty of well-executed 1095, in that it'll sharpen up like a breeze, with simple tools, but will still resist edge-rolling better than more wear-resistant steels (440C, etc) at lower RC hardness, and which are still more difficult to abrade (i.e., sharpen).

Steels like 440C, D2 or S30V are more difficult to sharpen, even at lower hardness, because the embedded carbides themselves are much, much harder* than the surrounding steel matrix, to which the RC hardness spec applies. This is why a 1095 blade will still be easy to sharpen at RC 60+, because there are no hard carbides in it. The high hardness rating reflects how well the steel will resist plastic deformation (denting/rolling, accounting for the majority of edge damage), but not how it wears by abrasion.

( * Chromium carbides by themselves would be HRC 70+, and vanadium carbides at HRC 80+ .)


David

 

[herisson]

"Case has already confirmed their Tru-Sharp is 420HC" !!!
Why, I am delighted ! The Case SS steel works great on any Case I have. Still looking for the CV models supposed to be so much better, but already impressed I am by Case and liking the brand.

 

[pinnah]

Really, finding the exactly the right steel isn't as hard as one might think to carry on a construction site. One would think that a "super steel" or some tremendously hard steel would be great. It isn't.

I am basing this on 40 years in the trades, most of it as a hands on carpenter/woodworking/finisher, so your mileage may vary.

My personal experience it that I prize the utility value of a knife first, and ease of maintenance second. Like almost all of my tools they are in my hands quite a bit, so they have to be comfortable to use and the right knife for the job. That's why I carry two all day. Second, I accept maintenance of any cutting edge (chisels, router bits, saw blades, etc.) as part of the package when using a tool. So I plan for sharpening.

I have found that opening bags of concrete with your work knife is equally hard on my S110V as it is on my 8CrMoV. When you nick an unseen nail, staple or wire with your 154cm, the edge rolls over just like it does with 1095. When you have to strip a large wire, large enough that your strippers don't go around it, cut a shingle, cut insulation, and on an on... there really is only marginal performance between a "super steel" and some oldies but goodies, 420HC being one of them.

The difference is that if you damage the edge by accident (which will happen a couple of three times a week) or need to refresh the edge after a good bit of cutting, you don't travel with your diamond sharpening gear, your strops, your edge setting jig etc. If you need to do some fine cutting after opening a few equipment boxes or fiberglass boom (load) straps, you can get a nice work edge with a piece of 800gr wet and dry sandpaper. You don't need anything else. This is really handy if you did nick a nail first thing in the morning, or you just want a tune up before installing moldings.

Again, anticipating maintenance, I tune up the edges on my knives in seconds. I cook almost every dinner we eat, and I always give my chef's knife a lick on my 1200gr diamond rod to refresh the edge, every meal. Usually, my small work knife is right behind the chef's knife, and a keen edge back in literally three or four swipes a side. For my larger, regular carry work knives which are all 420HC, AUS8, AUS10, and 8CrMoV, I mostly use a 600gr diamond rod. Accepting maintenance as part of tool use, I like to tune the edges up with just a few swipes on a rod any of my knives, not having to get out a setup to do so.

At one time I thought S110V at 61 Rockwell would be the answer for me. Spent $100 on a Shallot. Nope. Then at the suggestion of another BF denizen I tried a Benchmade with 154cm. Nope.

Really hard steels are too hard to maintain in the field, and are too time consuming to maintain to make them a worthwhile effort to be used as their primary work knife for any of my fellow tradesmen. The first time I cut through some really thick insulation and hit a couple of hidden runs of conduit with my Kershaw super steel and saw what it did to the blade was the last time it went to the job. I was really disappointed at the damage to the edge, but more importantly knew I couldn't fix it in the field. And so it sits in a box, while knives bladed in the steels mentioned above go to work every day and get it done.

Robert

Robert, although my "hard use" is much more pedestrian than yours, our experiences match, which is why I prefer 420HC or 12C27 over 440C for EDC use. I need better stones for my Lansky to stay on top of the 440C. This was the point I was trying to make with Phil.

This said, I've talked with guys in the trades who prefer the newer powdered steels. <shrug> That's cool. I'm still taking something easy to sharpen in the woods with me. :thumbup:

 

[pinnah]

Ease of sharpening the steel is essentially independent of the rated hardness of it; makes a small difference, but almost negligible. With a simple low-alloy steel like 1095, it has no hard carbides, which are what make steels like 440C more challenging (440C has heavy chromium carbide content). This has nothing to do with RC hardness, as the abrasion resistance (difficulty of sharpening) is related to the chromium- or vanadium-carbide content, and not the blade's RC hardness spec, which reflects the hardness of the steel matrix (independent of the carbides). This is part of the beauty of well-executed 1095, in that it'll sharpen up like a breeze, with simple tools, but will still resist edge-rolling better than more wear-resistant steels (440C, etc) at lower RC hardness, and which are still more difficult to abrade (i.e., sharpen).

Steels like 440C, D2 or S30V are more difficult to sharpen, even at lower hardness, because the embedded carbides themselves are much, much harder* than the surrounding steel matrix, to which the RC hardness spec applies. This is why a 1095 blade will still be easy to sharpen at RC 60+, because there are no hard carbides in it. The high hardness rating reflects how well the steel will resist plastic deformation (denting/rolling, accounting for the majority of edge damage), but not how it wears by abrasion.

( * Chromium carbides by themselves would be HRC 70+, and vanadium carbides at HRC 80+ .)


David

David,

On the first point, could you say more about this? Are you talking about 1095 vs 440C at 56Rc? 440C will roll more easily? I would think it would be more likely to fracture (at any Rc) than 1095, no?

On the second point, I wonder to what degree the availability of easy to carry diamond pocket stones like the DMT credit card stones (which I got on your recommendation and just love) change the equation by making previously hard to sharpen steels much easier (and cost effective) to sharpen?

I really need to get a medium diamond stone for my Lansky.

 

[davek14]

Ease of sharpening the steel is essentially independent of the rated hardness of it; makes a small difference, but almost negligible. With a simple low-alloy steel like 1095, it has no hard carbides, which are what make steels like 440C more challenging (440C has heavy chromium carbide content). This has nothing to do with RC hardness, as the abrasion resistance (difficulty of sharpening) is related to the chromium- or vanadium-carbide content, and not the blade's RC hardness spec, which reflects the hardness of the steel matrix (independent of the carbides). This is part of the beauty of well-executed 1095, in that it'll sharpen up like a breeze, with simple tools, but will still resist edge-rolling better than more wear-resistant steels (440C, etc) at lower RC hardness, and which are still more difficult to abrade (i.e., sharpen).

Steels like 440C, D2 or S30V are more difficult to sharpen, even at lower hardness, because the embedded carbides themselves are much, much harder* than the surrounding steel matrix, to which the RC hardness spec applies. This is why a 1095 blade will still be easy to sharpen at RC 60+, because there are no hard carbides in it. The high hardness rating reflects how well the steel will resist plastic deformation (denting/rolling, accounting for the majority of edge damage), but not how it wears by abrasion.

( * Chromium carbides by themselves would be HRC 70+, and vanadium carbides at HRC 80+ .)


David

Nicely put.

 

[winchester73]

Buck heat treat aside, is there that much difference between 420HC and 440A? Are they pretty close to the same?

 

[Obsessed with Edges]

David,

On the first point, could you say more about this? Are you talking about 1095 vs 440C at 56Rc? 440C will roll more easily? I would think it would be more likely to fracture (at any Rc) than 1095, no?

On that point, I'm essentially speaking to the (sometimes incorrect) assumption that any 440C or similar wear-resistant steel will always outperform a 'low wear-resistant' steel like 1095. Some will assume 440C and other steels will always hold up better. But, when talking about plastic deformation (rolling, denting), the wear resistance (dictated by the carbides) really doesn't affect it that much; the RC hardness will. So in stating that, I'm saying a 'low-wear' steel like 1095 at 60 RC will resist plastic deformation better than a 'high-wear' steel like 440C at somewhat lower hardness; in those terms, this is why something like 1095 can do better, if edge rolling or denting are primarily the issues faced in the use of a knife. This sort of touches on the point mentioned by Robert (midnight flyer), in saying that the 'high-wear' steels will still roll or dent just as easily, if the edge impacts something hard in cutting. Same damage, but the high-wear steels will be more challenging to fix, because the abrasion resistance affects that more, when 'abrasion' is the means by which it gets fixed.

As for fracturing, that depends more on hardness (if too hard, it's chippy or prone to brittleness) or grain size (larger grain tends to reduce toughness, i.e. resistance to fracture). Both of those factors will be affected more by heat treat, than by anything else. For example, during heat treat, grain size continues to grow larger until the steel is 'quenched' below a certain temperature. So, a faster quench will work to limit grain growth. Smaller grain makes for tougher steel, at least according to what I've read.

On the second point, I wonder to what degree the availability of easy to carry diamond pocket stones like the DMT credit card stones (which I got on your recommendation and just love) change the equation by making previously hard to sharpen steels much easier (and cost effective) to sharpen?

So long as the easy-to-carry diamond hone is in the pocket, no worries; it'll fix almost anything. Otherwise, as Robert also mentioned, a damaged blade in high-wear steel becomes a liability if the means to fix it isn't at hand. This is really one of the reasons why I'll never look down upon 'lowly' steels like 420HC, as I'm not the slightest bit worried about finding a means to fix a damaged edge (even heavily so), no matter where I happen to be. Same is obviously true for 1095. With 420HC, so far I've found good or even excellent means to sharpen it on diamond hones, SiC stones, AlOx stones, sandpaper and even a simple piece of red southwestern sandstone picked up from the ground. For a steel reputed for it's 'ease of sharpening', that speaks volumes to me and couldn't ring more true.


David

 

[Obsessed with Edges]

Buck heat treat aside, is there that much difference between 420HC and 440A? Are they pretty close to the same?

Wear resistance (resistance to abrasion by rubbing, scrubbing, grinding, etc.) is the big difference. In other words, the much greater chromium carbide content in 440C will help the steel in very abrasive cutting jobs (dirty cardboard, carpet backing, etc.). The RC hardness of each type will determine how well each resists things like edge rolling, denting or chipping, and the wear resistance (determined by carbide content) really won't play into that very much.

Playing into RC hardness, 440C has 2X the carbon content of 420HC (1.2% carbon in 440C, vs 0.6% at best, for 420HC), so a maker has some more headroom in hardening it to higher RC than with 420HC (like ~60RC for 440C, vs 58RC, which is pretty much the upper limit for 420HC).

Important edit:
I'm now noticing you're referencing 440A instead of 440C (jumped on that too fast ); it'll be more corrosion-resistant than 420HC, due to higher chromium in 440A (16% in 440A, vs ~13-14% in 420HC). The carbon content of each is relatively similar, so the edge-holding and wear resistance will be similar as well, assuming similar RC hardness levels. Hard carbides really aren't much of a factor at the carbon levels in each of these (both around ~0.6% or less).


David

 

[knarfeng]

Buck heat treat aside, is there that much difference between 420HC and 440A? Are they pretty close to the same?

The properties of 440A and 420HC are similar. But we've been talking about 440C, which is a considerably different beastie.

 

[pinnah]

As for fracturing, that depends more on hardness (if too hard, it's chippy or prone to brittleness) or grain size (larger grain tends to reduce toughness, i.e. resistance to fracture). Both of those factors will be affected more by heat treat, than by anything else. For example, during heat treat, grain size continues to grow larger until the steel is 'quenched' below a certain temperature. So, a faster quench will work to limit grain growth. Smaller grain makes for tougher steel, at least according to what I've read.

Which is to say, that all things being equal, large grained steel like 440C is more prone to micro-chipping than a fine grained steel like 420HC, correct?

This is Sandvik's marketing claim...
http://www.smt.sandvik.com/en/products/strip-steel/strip-products/knife-steel/knife-steel-knowledge/

 

[brownshoe]

I would sure like to see where Case came out and said what TruSharp really is;that would seem counter to good business.