GEC 440C cutting performance

So when they were ground the same, like a Buck 110 in BG42 vs. a 110 in 420HC, the BG42 pulled ahead again? But the geometry gave enough advantage to overshadow the benefits of the "better" steel? Was this based on edge angle only, or was it based on edge angle, thickness behind the edge and possibly final polishing grit? I add the grit aspect based on reading I did about the E2K being finished on a leather covered wheel.
 
me2 these tests by buck several years back are well documented & a classic attesting to the dymanics of edge bevel , blade thickness vs alloy resulting in ease of cutting coefficient resistance . these were scientific exhaustive tests which were universally accepted by the cutlery industry. in short , regardless of alloy the easiest cutting was accomplished with a acute edge bevel & thinnest blade stock.of course all other factors were equal which gives credence to the results.
 
me2 said:
So when they were ground the same, like a Buck 110 in BG42 vs. a 110 in 420HC, the BG42 pulled ahead again? But the geometry gave enough advantage to overshadow the benefits of the "better" steel? Was this based on edge angle only, or was it based on edge angle, thickness behind the edge and possibly final polishing grit? I add the grit aspect based on reading I did about the E2K being finished on a leather covered wheel.
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yes. When the BG42 had the old profile and the 420HC the new, the 420HC did better than the BG42. When both had the new profile, the BG42 did better. The measurements were made on a CATRA machine.

The Buck folks were not detailed in defining their final blade design (obviously), but from comparing their old blades to the new it was a combination of edge angle, thickness behind the edge, and shape of the blade overall. (The new profile includes an extreme hollow grind so that while the spine may still be thick, the edge and center of the blade are not.) Final polishing does not appear to enter into it.

Dennis is right. The information was freely available. Buck had a lot of this posted not only on BF but also on their own website for several years. When they revamped their web site a couple of years ago, the information on the edge 2000 work disappeared.
 
Nice job, Knarfeng! I like the aspect of visual examination for wear/sharpness/damage. But I do think that the thickness of the bevel, if unequal, could skew results.

Regarding the Buck tests, I will respectfully disagree with their value from a scientific perspective (I do agree with Knarfeng's conclusions about them) - I think the conclusion that thin cuts best is something that the cavemen knew. Buck's test was well designed to conclude exactly what Buck wanted to tell their customers, that their new (at the time) thinner blade could outperform a thicker blade made out of a superior steel. Interesting, yes, and great from a marketing standpoint, but hardly mind-blowing in what it tells us about edge retention.

It would be great to see more CATRA data for tests that only vary one cutting parameter, keeping every other variable as equal as possible. Be it steel, edge angle, bevel width, sharpness (how do you define sharpness?), or finish sharpening grit used (that would be interesting).

To accurately define blade/edge geometry, you need the same data the CNC machine has when it is cutting or grinding the blade, the positional coordinates. Even with perfectly flat geometry (ie. no curves - no convexity), you would need a number of angles and dimensions to describe the blade/edge. It would be similar to how an airfoil is defined - with x.y, and z coordinates - basically a CAD program. Not something that lends itself well to describing in words on the internet. I'll quit rambling now.
 
It's true that thin edges cutting better is just common sense, but it's mind-blowing just how big a difference it makes. About a year ago, I thinned my edge just 2 degrees per side (4 degrees thinner overall). I just cut cardboard until I can see light glint off the edge, and the edge holding of the thinner edge was nearly double! Since then, I've also been doing regrinds on my knives which further improve the performance. Of course, you need a minimum amount of hardness and toughness to support the thinner blade profile.
 
Dennis, it appears you feel I'm disputing the results. I was just trying to nail down the variables that were used and how they were compared to each other and changed. I've done several searches for this testing, but it appears to be gone from Buck's site, as noted earlier, as well as any other likely site. It sounds like they did do some single variable tests, like same geometry - different steel, but I don't know where to look to see for myself.

If I'm reading all of you correctly, then it confirms what I've suspected for a while, that geometry is at least as important as steel choice and heat treatment, if not more, though it is limited by the others.
 
I'd say blade geometry is more important than alloy. That's why them funny old fellas that hang out in Traditional and swear by Case True Sharp can use that alloy so successfully. Those old timey blade designs are thin. They don't need an uber alloy to cut well.

note: I have a white beard and hang out in Traditional a lot.
 
several years back ka-bar brought out a coupal of small synthetic handled skinners in 440a steel. blade or tactical knives had his story showing how a marginal alloy with a high thin bevel could perform so well. i bought a coupal & testing on cardboard showed that the high thin bevel cut longer than any knife i had previously tested.this confirmed what buck later demoed. the information i gleaned from this info was that although a marginal alloy could outcut [with thin bevels] much better steels with superior trace elements :if all bevels & blade thickness were the same the better alloy would excel . another conclusion was that all factors being equal the better alloy would show less wear & of course last much longer.this is the way i interpreted the info. hopefully my conclusions are valid.
 
several years back ka-bar brought out a coupal of small synthetic handled skinners in 440a steel. blade or tactical knives had his story showing how a marginal alloy with a high thin bevel could perform so well. i bought a coupal & testing on cardboard showed that the high thin bevel cut longer than any knife i had previously tested.this confirmed what buck later demoed. the information i gleaned from this info was that although a marginal alloy could outcut [with thin bevels] much better steels with superior trace elements :if all bevels & blade thickness were the same the better alloy would excel . another conclusion was that all factors being equal the better alloy would show less wear & of course last much longer.this is the way i interpreted the info. hopefully my conclusions are valid.me2 i did'nt wish to sound confrontational, i thought you did'nt see what the tests concluded.
 
No worries Dennis. I'm following a line of reasoning that may be obvious to some, but needs to be stated for me to get it.

If geometry has such a strong influence on edge retention, and thinner geometry holds an edge better, and higher end steels at the same geometry will out perform lower end steels, then all we have to do is determing what steel will take the absolute thinnest geometry that still resists damage (not just dulling) for the intended application. Anyone here willing to harden full flat ground 1/64" O1 stock to a 63-64 HRc?:D
 
me2 said:
No worries Dennis. I'm following a line of reasoning that may be obvious to some, but needs to be stated for me to get it.

If geometry has such a strong influence on edge retention, and thinner geometry holds an edge better, and higher end steels at the same geometry will out perform lower end steels, then all we have to do is determing what steel will take the absolute thinnest geometry that still resists damage (not just dulling) for the intended application. Anyone here willing to harden full flat ground 1/64" O1 stock to a 63-64 HRc?:D
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I'm testing O1 at ~64 rc range right now, it's at 18 degrees inclusive and is holding up surprisingly well. And yes, I would gladly harden some O1 for testing.

1084 would be the absolute best from the "edge stability" perspective though, as it's got no carbides and yet can reach the maximum martensitic hardness. O1 is basically 1084 with a few carbides thrown in.
 
If I had just bought that 1/32" O1 I've been lusting after. No carbides you say? But I like carbides, even the tiny ones in O1. Then again, do you have line on 1/32" cold rolled 1084?
 
me2 said:
If I had just bought that 1/32" O1 I've been lusting after. No carbides you say? But I like carbides, even the tiny ones in O1. Then again, do you have line on 1/32" cold rolled 1084?
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Hmmm I've never come across any 1/32" O1 or 1084 for sale. The only thin stock I've seen is in 52100 and 15N20.
 
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