Edge Retentions of Spycerco S30V vs. VG10 vs. Buck S30V vs. Benchmade D2

Benchmade pushes there hardness sometimes I think. I have a 1095 blade from them that is harder than several others I have in that steel - edge retention is improved. I am curious to know their hardness for S30V. Anyone have any numbers?
 
DennisStrickland said:
stress factors are actually are increadible at the edge since a very small amount of metal is actually pushing on the material that is cut. i've heard that in any single alloy that 2 points increase in rockwell increases the edge durability by 20%. simply said if you increase the rockwell of 1095 by 2 points , the durability of edge increases by 20%
dennis
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I'll be willing to bet that it's an exponential curve, not linear. You might get 20% from 56 to 58, but you go up to 65, and you'll see more like 300 - 400% increase, at least in my test runs.
 
Broos said:
Nice write-up. Have you noticed one edge cutting noticably better than another, with the wear appearing equal? It logically follows that increased wear will increase the force required to cut, but there could be exceptions - like the theory that D2 keeps cutting longer because of the way it wears (big jagged carbides being worn off leaving other big jagged good cutting carbides). Might require testing with duller edges to have a chance of observing this.

With hardness the best indicator of edge retention, and hardness being related to ultimate tensile strength, then it follows that edge retention is dependent on strength. This points to the major factor to dulling being the strength of the steel at the edge being exceeded by the pressure required to fracture the material being cut. This is obvious, but is still worth stating to emphasize the immense pressures of cutting & the role strength plays.
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I have noticed in my runs that some knives cut more easily than others. I have not made any real correlation between ease of cutting and performance in the tests. You raise a good point. I'll have to ponder that one.

I'm not sure that I agree that hardness is always the best indicator. As I stated in my conclusions, while hardness appeared to be the dominant factor in push-cutting type cuts, wear resistance appears to play a major factor if one is performing slicing cuts. For further confirmation, one need only look at hardheart's current fascinating thread about the CATRA results of various alloys
http://www.bladeforums.com/forums/showthread.php?t=769910
to see that wear resistance can make a major difference in performance. I dare say Bob Dozier could have dropped the hardness of the 10V a couple of points and still had it outperform the S30V.
 
A very nice job--matching geometries is the ONLY way to generate any kind of meaningful comparisons between alloys/heat treatments.

One thing I'm curious about---where on the knives did you do the cutting? If you were, for instance, to do this test with that Queen Stockman with the straight part of the blade, and then again with the belly out front, I think you would find that the curved section's slicing edge retention is superior to that of the flat section's, as the curve gets a more progressive move into the cutting medium and so has less pressure on it--which in turn means less stress/damage. Think of a hinged paper cutter versus a gillotine.

I'm not saying the differences would be huge, but the variances in curvature between the blades do have some effect on their shearing characteristics...although you might have already thought of that.

Ideally, not only the grind angles but also the actual blade shapes would be identical. Alas, those goofy manufacturers all have their own ideas about what shape the blades should be. :D

Anyway, this isn't a quibble, just an observation. Still a very streamlined, controlled process, and one of the EXTREME few that I think actually deserves to have the name "test." Many will post comparisons/conclusions based on "data" that's so ridiculously skewed that I sometimes wonder if they're kidding.
 
Thanks for the tests!

It makes me wonder why more makers dont use D2. I know some people have trouble putting an edge on D2 whereas S30V seems to sharpen up a little easier.

I remember reading somewhere that CRK and others have adopted S30V because they consider it the ideal cutlery steel for people who want a knife that will cut well enough for most tasks but still sharpens up easily enough. I think even a lot of knife freaks have trouble putting a good edge on knives so when it comes to certain 'super steels', people may be reluctant to try them purely because they fear not being able to keep the knife sharp.

What they dont realise is that if ZDP-189, S90V and the like have a decent edge in the first place, you only have to touch them up occasionally to keep them that way because the steel is so freaking hard it's next to impossible to blunt the edge in the first place.
 
More and more diamond sharpeners are becoming available, so steels that used to be considered "hard" to put an edge on like 440C really aren't too bad at all. The flip side of that is that fewer and fewer people out there have the patience or interest in developing a skill like sharpening, and so still don't make use of the better steels.
 
t1mpani said:
A very nice job--matching geometries is the ONLY way to generate any kind of meaningful comparisons between alloys/heat treatments.

One thing I'm curious about---where on the knives did you do the cutting? If you were, for instance, to do this test with that Queen Stockman with the straight part of the blade, and then again with the belly out front, I think you would find that the curved section's slicing edge retention is superior to that of the flat section's, as the curve gets a more progressive move into the cutting medium and so has less pressure on it--which in turn means less stress/damage. Think of a hinged paper cutter versus a gillotine.

I'm not saying the differences would be huge, but the variances in curvature between the blades do have some effect on their shearing characteristics...although you might have already thought of that.

Ideally, not only the grind angles but also the actual blade shapes would be identical. Alas, those goofy manufacturers all have their own ideas about what shape the blades should be. :D

Anyway, this isn't a quibble, just an observation. Still a very streamlined, controlled process, and one of the EXTREME few that I think actually deserves to have the name "test." Many will post comparisons/conclusions based on "data" that's so ridiculously skewed that I sometimes wonder if they're kidding.
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I try to stay on a straight section of the blade, typically 2 to 2 1/2 inches in length. I often mark out where I am going to start and stop cutting. Whatever length I use, I use the same length of blade for each knife.
 
It makes me wonder why more makers dont use D2.
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Makers that like putting a high polish on their blades will at times steer away from D2 ( and S30V) due to the steel being notoriously difficult and time consuming to finish to high grit levels. D2 even has a kind of orange peel effect even when mirror polished.

Like any other vocations people have preferences and dislikes.

I don't agree with this but how many times have we heard that "D2 takes a lousy edge and holds it forever".

Though not my favorite steel I do like D2, and CPM D2 but if I had to put out a certain amount of knives per month to survive I'd be looking at steels like AEBL, ATS 34, 154cm, and CPM 154, and in carbon /alloy steels I'd be pushing 5160, 1084, 1095, etc.

Steels like 10V, S110V, S90V, would be rare, special order only with prices to match the extra time, abrasives, higher temps etc. One could probably make 1.5 to 2 -12C27 knives for every knife made out of S110V.
 
The difference is probably much higher than that. 12C27 is cheap to buy, cheap to shape by fine-blanking, cheap to grind, cheaper to heat treat, and cheaper to finish.

D2 isn't quite stainless, another hindrance.
 
The Mastiff said:
Makers that like putting a high polish on their blades will at times steer away from D2 ( and S30V) due to the steel being notoriously difficult and time consuming to finish to high grit levels. D2 even has a kind of orange peel effect even when mirror polished.

Like any other vocations people have preferences and dislikes.

I don't agree with this but how many times have we heard that "D2 takes a lousy edge and holds it forever".

Though not my favorite steel I do like D2, and CPM D2 but if I had to put out a certain amount of knives per month to survive I'd be looking at steels like AEBL, ATS 34, 154cm, and CPM 154, and in carbon /alloy steels I'd be pushing 5160, 1084, 1095, etc.

Steels like 10V, S110V, S90V, would be rare, special order only with prices to match the extra time, abrasives, higher temps etc. One could probably make 1.5 to 2 -12C27 knives for every knife made out of S110V.
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Interesting. I haven't yet had a problem getting great mirror finishes on my D2 knives. I've heard that saying also, but with my Doziers, D2 takes a superior edge and seems to hold it almost forever. It's one of my favorite steels, and if the grind is well done, very quick and easy to sharpen.
 
franks tests have certainly generated a lot of interest & more importantly a ton of non adversive information . the contributions by fellow formites has certainly been a positive contributory windfall with the additional thoughts concerning edge curverature , edge abrasion durability in a logritic curve at higher rockwells, & the factors of use by manufactuers of the more exotic alloys in finished products. i particularly enjoyed the comments since they were added in a positive nonargumentive format.
dennis
 
I would love to see tests on, say, 9 identical knives that vary 1 pt. in HRC. Like 9 or 10 Spyderco mules in one steel ranging from 55 to 65 HRC. That would be very, very interesting.
 
Do you think that the recurve on the 710 could have contributed to the better push-cutting ability?
 
sodak said:
I would love to see tests on, say, 9 identical knives that vary 1 pt. in HRC. Like 9 or 10 Spyderco mules in one steel ranging from 55 to 65 HRC. That would be very, very interesting.
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Ah, laddy that's no likely, though I'd love to be involved in a project like that. They'd bring in the A-team for expensive testing like that for sure. If ye've no figured it out, I test on a restricted budget. One of the parameters in the development of my test setup is that it could not require expensive equipment.
 
THG said:
Do you think that the recurve on the 710 could have contributed to the better push-cutting ability?
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No sir, I do not.
I used a section that was pretty straight for the cutting. I think it was the difference in hardness.

To be truthful I think I need to take the D2 off my chart, but for a different reason. Most of the others alloys are 59±1 HRC. To compare those to something over 61 isn't a square comparison. But what's a mutha to do? D2 works optimally at a higher hardness than the other alloys. Rats!

The issue is one that bothers me. One the prerequisites for my comparisons was that I would test the alloys all at the same hardness so that I would be testing the inherent difference in the alloy, not the heat treat. However, D2 can easily be taken to a significantly higher hardness than the other alloys. That adds back in the second factor that I was trying to eliminate.

I suppose I could try to find a D2 blade hardened to a 59, but I'll have to figure out who offers one. Bugger!
 
IIRC (I might not be), the Benchmade 180 Outbounder (a McH-W collab) was spec'd in the 58-59 range when BM upgraded the knife to D2 for the last run.

When they replaced this in the line with the Snody Activator, I believe hardness moved up 2-3 points.

If I am remembering all of this correctly, and if you want to proceed, I could loan you my D2 180 - post here and I'll send contact info. No offense taken if you're not interested or if I'm yet again manifesting EOAS.

knarfeng said:
No sir, I do not.
I used a section that was pretty straight for the cutting. I think it was the difference in hardness.

To be truthful I think I need to take the D2 off my chart, but for a different reason. Most of the others alloys are 59±1 HRC. To compare those to something over 61 isn't a square comparison. But what's a mutha to do? D2 works optimally at a higher hardness than the other alloys. Rats!

The issue is one that bothers me. One the prerequisites for my comparisons was that I would test the alloys all at the same hardness so that I would be testing the inherent difference in the alloy, not the heat treat. However, D2 can easily be taken to a significantly higher hardness than the other alloys. That adds back in the second factor that I was trying to eliminate.

I suppose I could try to find a D2 blade hardened to a 59, but I'll have to figure out who offers one. Bugger!
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