M390 VS ZDP-189 Rope Cutting - Informal testing

STR said:
Jim great test and thats a lot of rope! Looking at the pictures its just a curious point really but is the Spyderco like significantly older than the BM? I know you haven't had the BM long. The reason I ask is because of what we talked of earlier. I wonder how much of the 'perceived effort' is due to the Spyderco being sharpened down so because it appears in the pictures that the edge is a bit more obtuse than the new fresh out of the box BM.

The results may be closer to each other than realized due to the more obtuse edge of the Spydie. Still though it sounds like the M390 is a top contender. Thanks for all the blisters! :D

By the way, forgive me if I've just brought up something already asked and answered. Guilty of not reading all posts as usual here. ;)
STR
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It's not that old, I got it in July this year. :D

It has seen a ton of testing and reprofiling, sharpening etc, I thinned out the edge to minus -9 degrees per side and then had to put a 15 degrees per side micro bevel on it.

One day I need to really thin it out again, but for now it still cuts very well.

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Sal, RC 60 seems optimum for S-90V. As you know that is pretty close to the obtainable hardness. I still make some fillet knives with this steel and can cut through the hard bones on a Striped Bass or large Salmon without any damage to a thin edge (.008) I also have a Chef's in the kitchen that sees some chopping action on taking a chicken apart ect once in a while and it is holding up ok. I would rather hit my thumb with a hammer than make another large Chef's with this grade though. Phil

Vaslli, I hope I did not come accross as angry in our discussions. Certainly sarcastic but that is me. I also invited you to come to my shop and do some cutting and psycho knife babble but only silence from you on that. I have since withdrawn the invite due to just to busy and don't think we would hit it off to well. Phil
 
Jim, your Endura ZDP does look like it has been through a lot! I can tell that from how
much Blade height there is left!


I have yet to take a V-grind knife under 15 degrees a side, but have just done a Chisel grind Emerson CQC7 to 21degrees inclusive/per side.

Your tips, tricks, recommendation all worked very well together and I'm extremely pleased.

Aside from that, I admire your Manilla Rope testing very much and I do hope that we can one day link our results together. I will try and mimic your equipment(Wooden board as backing, .5" Manilla Rope)

I'm sure if more than one person does it, we can expand this "test" and have more steels to test as well.

P.S. Phil Wilson, I'm glad to see you shedding incremental amounts of your knowledge here. I've been trailing your work for a couple years now:thumbup:
Thank you very much to both Jim and Phil
 
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Phil Wilson said:
Sal, RC 60 seems optimum for S-90V. As you know that is pretty close to the obtainable hardness. I still make some fillet knives with this steel and can cut through the hard bones on a Striped Bass or large Salmon without any damage to a thin edge (.008) I also have a Chef's in the kitchen that sees some chopping action on taking a chicken apart ect once in a while and it is holding up ok. I would rather hit my thumb with a hammer than make another large Chef's with this grade though. Phil
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Thanx much Phill, that's what we came up with as well.

I do not envy you to make a large chef's knife out of S90V.

Does your S90V filet knife flex at the tip in the manner you normally use in your filet knives? I know you use very thin tips. Have you ever broken the tip?

sal
 
Phil Wilson said:
Vaslli, I hope I did not come accross as angry in our discussions. Certainly sarcastic but that is me. I also invited you to come to my shop and do some cutting and psycho knife babble but only silence from you on that. I have since withdrawn the invite due to just to busy and don't think we would hit it off to well. Phil
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Well, I am still waiting for you to make this simple device - wood with partial cut to do correct testing.

But instead of discussing this particular problem, which is pretty easy to fix you starts all that drama, and I do not have answer for several years from you.

Is it too hard to make partial cut -half cut in 4x4 piece of wood?

Why do you ignoring this obvious flaw in your tests for all this years?

Thanks, Vassili.
 
DennisStrickland said:
got to love it when the big dogs start talking alphabet alloys. thanks jim for rolling this ball.
dennis.
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Yeah when they start talking it's time to sit back and listen and take it all in. :D :thumbup:

Lots of great info Coming from Sal Glesser and Phil Wilson. :)

I am just sitting back and taking notes. :D

These guys are the real experts and I am humbled by their presence in my thread. :)
 
nozh2002 said:
Well, I am still waiting for you to make this simple device - wood with partial cut to do correct testing.

But instead of discussing this particular problem, which is pretty easy to fix you starts all that drama, and I do not have answer for several years from you.

Is it too hard to make partial cut -half cut in 4x4 piece of wood?

Why do you ignoring this obvious flaw in your tests for all this years?

Thanks, Vassili.
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at least in my mind, your "solution" fixes little, if anything.

the downward force of the cutting will ineventably lead to contact between the edge and wood. because the contact would also be partly determined by the amount of force and the cutter's ability to stop the downward force, contacts would be inconsistent and immeasurable in the overall outcome.

as it is, the edge will contact the wood with every cut. and with the cutter not concerned with stopping the downward force, contacts will be far more consistent.

i suppose one could make the cut several inches deep, and use a thicker piece of wood.

but how wide should the cut be? the narrower the better, since the rope would sag in to a cut that was too wide. but if its narrow, it would be more difficult to accurately cut the rope and have the blade slide in to the groove. the end result is probably a few contacts with the wood, which again would be inconsistent from knife to knife.

the testing is fine as it is.
 
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Lay a pair of two by fours (or smaller for a small knife) parallel to each other on a table, flush with the edge of the tabletop and with just enough space to lay the rope between. Have a half inch or so of rope hanging over the edge, lay the knife flat against the end of the table/two-bys, and slice the rope. The only way for the edge to contact anything but rope is to drop it on the floor.

Or clamp the knife in a vise edge up and the point facing away from your belly and slide the rope over the edge to cut it. Not the safest for your thumbs, but we must sacrifice for science :).
 
In rope cutting, it's critical that there is no flex in the rope. If the rope flexes, the compressed part will be right under the edge and the compressed rope is harder to cut.

Loop a coil of hemp, pull cut through the center of the loop, then loop again and begin your pull cut along the side below the center of the loop and you'll feel the difference.

The slot in the wood would have to be very thin, which makes it easy to miss, or wide which permits rope flex.

sal

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We are all teachers and we are all students.
 
hardheart said:
clamp the knife in a vise edge up and the point facing away from your belly and slide the rope over the edge to cut it. Not the safest for your thumbs, but we must sacrifice for science :).
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You're funny. :D

Science doesn't know much 'bout knives. We at BF be the eggsperts. ;)

sal
 
Sal Glesser + Phil Wilson = Pure Class and a wealth of information. Lucky to have them here, it's actually an honor. Great time to be a knifenut I'll tell you. :)
 
Sal Glesser said:
Thanx much Phill, that's what we came up with as well.

I do not envy you to make a large chef's knife out of S90V.

Does your S90V filet knife flex at the tip in the manner you normally use in your filet knives? I know you use very thin tips. Have you ever broken the tip?

sal
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Wouldn't that be another reason to have a look at M390 or the other variants? I assume it would be easier to machine having only 4% vanadium compared to the 9% in S90V. And I did hear rumors about high carbide steels being prone to chipping and micro-chipping(I'd think ZDP-189 would be a testament to that). So M390 seems to balance that out a bit.

I'd put M390 somewhere between S30V and S90V just in general. Not as frustrating to machine as S90V, but more wear resistant than S30V. But the curious thing to me is that the steel seems to be regularly found at around Rc 60-62, which makes me wonder if it isn't also easier to consistently heat treat at that range. Most production knives with S30V seems to have it around Rc 58-60.
 
Thanx for the kind words. But Phil and I are just like you, only older. When we were younger, we had others to learn from. Some of us like to learn. Testing is a great way to learn.

The knife industry is an amazing and unique industry. It's surpising how much is still to be learned, despite it's history.

I have a great deal of respect for Phil for his "truth seeking" passion. Ask him how many heat sensors he has in his oven to make sure that each part of the oven is getting even heat. ;)

sal
 
Noctis3880 said:
Wouldn't that be another reason to have a look at M390 or the other variants? I assume it would be easier to machine having only 4% vanadium compared to the 9% in S90V. And I did hear rumors about high carbide steels being prone to chipping and micro-chipping(I'd think ZDP-189 would be a testament to that). So M390 seems to balance that out a bit.

I'd put M390 somewhere between S30V and S90V just in general. Not as frustrating to machine as S90V, but more wear resistant than S30V. But the curious thing to me is that the steel seems to be regularly found at around Rc 60-62, which makes me wonder if it isn't also easier to consistently heat treat at that range. Most production knives with S30V seems to have it around Rc 58-60.
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Hi Noctis,

CPM-S90V is among the best edge holders that we've tested, at least on CATRA. I think it's the many big vanadium carbides and the Crucible processing. S150V, then S125V, then S110V. Then ZDP and S90V are close despite their totally diffferent chemistry paths to get there. So I use them as kind of a goal.

M390 may prove to be exceptional and as you say, a good synthesis. Time and testing will tell.

We're still learning about ZDP as there is not much history in production pieces. We're planning more S90V.

I'm looking forward to releasing the M390 mule so we can get more "Real-world" testing on this new steel in a format that is similar to other pieces.

Some of the new steels from now available from Carpenter, Uddeholm, SandviK and others will be fun for steel-heads.

sal
 
Sal Glesser said:
In rope cutting, it's critical that there is no flex in the rope. If the rope flexes, the compressed part will be right under the edge and the compressed rope is harder to cut.
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fair enough, plus it tends to not cut straight. Just figured if doing the same thing with the tested blades, while testing until it behaves differently on another medium (stops shaving, shaving arm hair, etc) instead of measuring force on the rope itself would be one way to address the concerns of the edge contacting something other than the rope.

I also considered just not cutting all the way through the rope, using a depth stop of some sort, like a groove in the board to lay the rope in. This would be for push cutting, so the edge cutting the rope doesn't touch the wood, the point of contention here.
 
My Endura might be beat up worn down and getting tired but it will still cut. :D

[youtube]MB5wjv-Yt6E[/youtube]
 
Sal, I grind the fillet knives so that the first half of the blade has most of the flex. I have had a few fillet knives come back to fix. On one the guy said the jabbed a rock fish in the head since it was flopping around on the deck. Impact force and some twist will do it every time. His 9 inch fillet knife is now a 7 inch fillet knife. With S90V at RC 60 I can flex a fillet knife against a board with enough force that it will actually stay bent a little. It can then be flexed back the other way and straighten out. Can do the same with CPM 154 and S30V as well. These steels all are pretty forgiving in bending. I would like to work more with ZDP 189 but can't get the steel-- and then hard to get any heat treat info out of Hitachi. I made one with some clad ATS 34 on the outside. I did get it to RC66 and it did ok cutting but can get pretty much the same results from CPM S90V . Easy steel to get and lots of help from Crucible on heat treating it. Seems like Bohler is really interested in furnishing the blade steels and they have some real interesting grades. Just finished a hunting knife with K294 which is their version of A11 (CPM 10V). Anyhow it is getting hard to keep up with all the various steels out there. Phil
 
Sal Glesser said:
We're still learning about ZDP as there is not much history in production pieces. We're planning more S90V.

I'm looking forward to releasing the M390 mule so we can get more "Real-world" testing on this new steel in a format that is similar to other pieces.

sal
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That's a big *yes* on more S90V. On the other Mules, what about trying to squeeze in one or two reference Mules in "ordinary" (hah, I guess "common" would be a much better word?) steels like VG-10 or 154CM? It would add to the ability to make comparisons, I think. :thumbup:

Sal Glesser said:
You're funny. :D

Science doesn't know much 'bout knives. We at BF be the eggsperts. ;)

sal
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The thing is that some of us here be a little scrambled, a few are cracked, and many of us are "just yolks." ;) :D
 
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