What steel do you find has the best "fine edge retention" ?

[chuck_roxas45]

That predetermined results that I hinted at before in the other post.

I doubt it was done on purpose, it's just that the reference that Cliff was trying to make in that the comparison was the steels is wrong.

It was a knife comparison..... The steels don't matter...

Kinda like comparing a Busse FFBM to an SAK... And then wondering why the SAK out cuts it. :D

This^^.

[Stuart Ackerman]

Some of you might know that VG10 or Bohler N690, is my favourite steel...
Yes, I know that they are different manufacturers, but they are essentialy similar, shall we say?

I know the HT, the most effective grind with the correct belts, the best way to finish, etc...

Most folk want the so-called super steels, I want this...easily pleased I am...

[chuck_roxas45]

Some of you might know that VG10 or Bohler N690, is my favourite steel...
Yes, I know that they are different manufacturers, but they are essentialy similar, shall we say?

I know the HT, the most effective grind with the correct belts, the best way to finish, etc...

Most folk want the so-called super steels, I want this...easily pleased I am...

Yep, I like VG-10 a lot too. It's really not about this steel vs. that. It's the method used and the "conclusions" stating that this steel is such and such, when the method is obviously just pitting one blade geometry vs. another. :)

[Cheygriz]

S90V, CPM M4, M390 and Elmax. As my experience with k390 increases, it is becoming the new favorite.

[Ankerson]

S90V, CPM M4, M390 and Elmax. As my experience with k390 increases, it is becoming the new favorite.

Yeah K390 is doing really well from what I have seen so far, I cut up 5 large cardboard boxes and it still shaved hair and sliced phone book paper after.

Estimate is between 200 ~ 300 yards of cardboard cut.

[me2]

The best I've tried so far was M2. It would still shave above the skin after 30 feet of cardboard.

[Cliff Stamp]

The price of the knives doesn't matter at all, they are what they are, one is a tank blade and edge geometry wise and the other is a slicer.

Jim,

The Delica which was used was a stock one with the short sabre-grind, same as the Hinderer, the edge thickness are similar and the and the angle on the Delica was 17 dps vs 20 dps on the Hinderer.

As noted, edge stability is biased in favor of the Hinderer, not the opposite as you inferred.

So it was comparing knives, not steels and the Spyderco should have performed better due to better edge and blade geometry, and it did, was no surprise to me at all and I knew what was going to happen before the results were even posted.

No, the Hinderer had the material advantage for reasons noted as it was at a higher angle and thus would have a more stable edge due to the shape. The edge stability would decrease as the angle was lowered, not increase.

Again, the results Chris obtained are consistent with known metallurgy, 20CV does not have an edge stability advantage over VG-10, these are materials facts.

So going by your logic here you are trying to say that a 3/16" thick blade that is .035" plus behind the edge and 20 DPS should perform better than another knife that is 1/8" thick, .010" behind the edge and 10 DPS with the same steel.

It would depend on what you were comparing them to do, and the knives in question are not even remotely similar to the difference you just noted.

[Ankerson]

Jim,

The Delica which was used was a stock one with the short sabre-grind, same as the Hinderer, the edge thickness are similar and the and the angle on the Delica was 17 dps vs 20 dps on the Hinderer.

As noted, edge stability is biased in favor of the Hinderer, not the opposite as you inferred.



No, the Hinderer had the material advantage for reasons noted as it was at a higher angle and thus would have a more stable edge due to the shape. The edge stability would decrease as the angle was lowered, not increase.

Again, the results Chris obtained are consistent with known metallurgy, 20CV does not have an edge stability advantage over VG-10, these are materials facts.



It would depend on what you were comparing them to do, and the knives in question are not even remotely similar to the difference you just noted.

Actually no....

It's basic physics....

The steeper the angle and thicker the blade the more force it will take to push it through the media compared to a blade that has a narrower angle and thinner blade geometry so the blade that is thicker with the steeper edge geometry will suffer edge damage sooner due to the pressure increase needed to move it through the media.

The blade with the thinner geometry will always have the advantage in general over the thicker one in cutting because it's more efficient moving though the media being cut.

And you already know that........ Having a PHD in Physics......

[Donut]

The best I've tried so far was M2. It would still shave above the skin after 30 feet of cardboard.

That sounds pretty nice. I'll have to try and get something in M2 to try out.

[Cliff Stamp]

It's basic physics....

No Jim.

The increased force in the cut due to a thicker blade isn't on the apex it is a wedging force on the side of the blade. Thus you can not simply say more force on the blade = more force on the apex.

It isn't simply a matter of noting the force increases/decreases you have to know how the increased force is applied to the blade to figure out what will happen to the edge because it might not even increase the force on the edge at all.

In this case the forces used in the cutting are very comparable as the blades are within 10% of each other in the most different aspect (edge angle) so it is a completely nonsensical argument to make as that is inside the expected measurement scatter.

However in the case when they are significantly different (if the Delica was a Opinel for example with a 10 dps edge) then you have to determine if those forces actually cause a higher force on the apex directly and if this is more than what is necessary to over come the increased stiffness of the apex.

Since the stiffness is cubic with perpendicular dimension this means that it is rarely the case that increasing the edge will actually cause premature failure in the manner in which you would suggest. This is why of course if you take a Mora for which the edge is rolling and increase the edge angle it doesn't then start rolling more.

Now, when this actually becomes a problem is when the increased forces on the side of the blade cause the blade to experience lateral forces during the cutting. This normally happens in chopping and the reason it happens here is loss of stability due to lack of penetration in the cutting. If this happens you can get very significant effects because the blades are much weaker in lateral loads than they are in compression.

Again, what Chris saw is consistent with the known materials properties of those steels and if the Hinderer was reground to 17 dps the edge stability would decrease it would not increase. That is the actual known physics.

[Ankerson]

No Jim.

The increased force in the cut due to a thicker blade isn't on the apex it is a wedging force on the side of the blade. Thus you can not simply say more force on the blade = more force on the apex.

That depends on the media being used really, it is true in general what you said, but it could also increase the force in the apex depending on the variables.

That's why the blades need to be close to the same as they really can be to get a more accurate result for the data.

It isn't simply a matter of noting the force increases/decreases you have to know how the increased force is applied to the blade to figure out what will happen to the edge because it might not even increase the force on the edge at all.

Again true, it might not, but then it might and that is my point.

In this case the forces used in the cutting are very comparable as the blades are within 10% of each other in the most different aspect (edge angle) so it is a completely nonsensical argument to make as that is inside the expected measurement scatter.

+ or - 10% is pretty small, but it could have an effect, but then doing it by hand it may or may not matter.

However in the case when they are significantly different (if the Delica was a Opinel for example with a 10 dps edge) then you have to determine if those forces actually cause a higher force on the apex directly and if this is more than what is necessary to over come the increased stiffness of the apex.

Since the stiffness is cubic with perpendicular dimension this means that it is rarely the case that increasing the edge will actually cause premature failure in the manner in which you would suggest. This is why of course if you take a Mora for which the edge is rolling and increase the edge angle it doesn't then start rolling more.

Yes, in general if the edge is rolling an increase in angle would be needed to stabilize the edge. But that's metallurgy and the variables of the said blade and the steel will have an impact on what angle the edge is stable.

Now, when this actually becomes a problem is when the increased forces on the side of the blade cause the blade to experience lateral forces during the cutting. This normally happens in chopping and the reason it happens here is loss of stability due to lack of penetration in the cutting. If this happens you can get very significant effects because the blades are much weaker in lateral loads than they are in compression.

That's were things get blurred and people start to lose their understanding of what is really happening so we really need to be clear on what we are stating. Or they could be taken out of context.

Again, what Chris saw is consistent with the known materials properties of those steels and if the Hinderer was reground to 17 dps the edge stability would decrease it would not increase. That is the actual known physics.

In theory yes.

But.

That would depend on the actual media being cut, and if the pressure on the apex decreased or not, now if both blades were the same, it would have been a better comparison. Just too many variables to make a real conclusion.


The knives are different, so in retrospect the comparison would really need to made with knives that have the same edge and blade geometry to get a clear result.

The variables are there so a conclusion can't really be made as an absolute answer, but then there aren't really any absolute answers to start with.

[me2]

Unfortunately, the source for this is gone, at least my source. I think CPM M4 would do this too, but it would need to be hardened properly. I suspect something like O1 could do it too, but the HT would have to be dead on.

[me2]

I don't really want to discuss it here beyond one post, so I'll be concise.

The Delica was sharper than the XM-18 after the same amount of cutting. The Delica was thicker behind the edge than the XM-18. The XM-18 had a slightly higher edge angle. All the tests are intended to minimize geometry effects, from the cutting of short and narrow strips of 1/8" cardboard to minimize binding, to the use of push cutting thread to remove the effect of geometry from the sharpness test. I've stated before that I test for high sharpness edge retention as measured by push cutting. This closely simulates how I use and when I sharpen my knives. I also compared the XM-18 to a RADA Cutlery paring knife in cutting wire (bread ties) and edge holding. The XM-18 had no advantage I could detect in either case, though it had the same increase in bevel angle over the RADA that it had over the Delica. If 3 degrees per side masks the difference between 20CV and 420HC, we're all wasting our time testing for edge holding.

[dschur]

I will say ZDP-189, followed by S90v then M390 for me.

Don't know why, but for me with a low angle edge there's something about that ZDP.

[3rdGenRigger]

My only experience with ZDP-189 is the Nishijin Dragonfly I recently acquired and it seems to be holding an edge exceptionally well. So well I bought my dad a Delica 4 in ZDP-189 to try out because I want his opinion on it as well. It just might be my new favourite. It's also the sharpest Spyderco I've bought out of the box, second probably to my Chokwe.

[me2]

I really need to try a Delica or Endura in ZDP.

[Cliff Stamp]

That depends on the media being used really, it is true in general what you said, but it could also increase the force in the apex depending on the variables.

Yes Jim and that is why you need to do the physics noted which has been done for the cutting in question and is in general Chris does submit his work for peer review and his methods/results are actively discussed on the forum.

To be specific :

XM-18 :

-secondary, 0.027"/18(1) dps
-primary, 0.14"/4.5 (5) dps

Delica :

-secondary,0.033"/15 (1) dps
-primary, 0.1"/6.5 (5) dps

The geometries are very similar hence the force in cuts are also similar. Note that the Delica actually has the thicker edge and thicker primary grind, not the Hinderer. However it is balanced by the slightly lower edge angle which is +/- 5% from each blade and thus the general cutting ability is not significantly different.

To be specific, slicing 1/8" ridged cardboard on a slice where the travel was 5x the draw on a 45 degree blade/cardboard angle, it was 1.5 (5) lbs to make a slice with both blades. Enough to deflect a standard scale but just barely and not significant.

There is no significant difference in force in the cutting and thus it isn't a factor in the edge retention testing that Chris did, and even if it was then it would be wedging, not against the apex for reasons noted in the above.

The reason the Delica was chosen to accompany the XM-18 in the passaround is because it compares very well in many respects including general cutting ability. The XM-18 in question has the slicer grind which is Hinder's version of a high performance cutting grind.

As always the point of the passaround and benchmarks in general are to provide references, they are not simplistic pass/fail points.

[Ankerson]

Yes Jim and that is why you need to do the physics noted which has been done for the cutting in question and is in general Chris does submit his work for peer review and his methods/results are actively discussed on the forum.

To be specific :

XM-18 :

-secondary, 0.027"/18(1) dps
-primary, 0.14"/4.5 (5) dps

Delica :

-secondary,0.033"/15 (1) dps
-primary, 0.1"/6.5 (5) dps

The geometries are very similar hence the force in cuts are also similar. Note that the Delica actually has the thicker edge and thicker primary grind, not the Hinderer. However it is balanced by the slightly lower edge angle which is +/- 5% from each blade and thus the general cutting ability is not significantly different.

To be specific, slicing 1/8" ridged cardboard on a slice where the travel was 5x the draw on a 45 degree blade/cardboard angle, it was 1.5 (5) lbs to make a slice with both blades. Enough to deflect a standard scale but just barely and not significant.

There is no significant difference in force in the cutting and thus it isn't a factor in the edge retention testing that Chris did, and even if it was then it would be wedging, not against the apex for reasons noted in the above.

The reason the Delica was chosen to accompany the XM-18 in the passaround is because it compares very well in many respects including general cutting ability. The XM-18 in question has the slicer grind which is Hinder's version of a high performance cutting grind.

As always the point of the passaround and benchmarks in general are to provide references, they are not simplistic pass/fail points.

Interesting, kinda thick for a Delica, even the sabre grind ones from what I have seen over the years, usually in the .025" range, FFG ones are slightly thinner in the .020" range.

Also kinda thin for the XM-18 even with the slicer grind as they are usually still over .030" even with that grind and in the .045" range with the standard grind. The reason why I never got one even with the slicer grind because they where too thick.

However if that's what you say they are then so be it.

[kennethsime]

I really need to try a Delica or Endura in ZDP.

Better yet, split the difference and add a choil! Get a Stretch!

[Cliff Stamp]

I really need to try a Delica or Endura in ZDP.

Easily done, send me an email.