I dropped my CPM-4V Manix tip down on cement!!

SubMicron

SubMicron

Joined
Feb 2, 2020
Messages
335
After installing a deep carry pocket clip, while rubbing EDCi Corrosion Inhibitor on my CPM-4V Manix 2, the thing jumped out of my hand while open!!!

A noble effort was made to catch it, but there's not a lot that can be done with a falling and spinning blade.

I must have closed my eyes for the impact on the cement floor.

When I picked it up, all I saw was a bunch of white powder at the tip... the worst case scenario... Not a single mark anywhere else... the tip took all of the energy of the fall, strait onto the cement.

My heart sunk.

I cleaned the tip.... I cant find any damage!!

It put a hole in my cement floor!!!

Good job Spyderco!

Screenshot_20200611-084210_Gallery.jpg
 
The problem is that it's now one of many holes and dings. It's one of the first things I looked for after checking the tip.

There's one that I think is from the knife, but it seems awfully big.

Tonight after work I'll check the floor with a flashlight and see if I can figure it out.
 
Wow that’s pretty impressive! That steel is around 64HRc and is that tough...don’t see that much! I still kick myself for not buying a 4V Fradon Manix.

It seems like 4V might actually be the best all around tool steel on the market right now, even more than Cruwear (heresy!) and Rex 45 / M4 (double heresy!)
 
John_0917 said:
It seems like 4V might actually be the best all around tool steel on the market right now, even more than Cruwear (heresy!) and Rex 45 / M4 (double heresy!)
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I'm reminded of the Eagles song, "New Kid in Town":

"They will never forget you 'til somebody new comes along"
 
John_0917 said:
It seems like 4V might actually be the best all around tool steel on the market right now, even more than Cruwear (heresy!) and Rex 45 / M4 (double heresy!)
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I agree.

Cruwear simply lacks the edge retention of the others, and its strengths center around toughness while still providing more edge retention than most people need.

CPM-4V is competitive with M4 and REX-45 for edge retention. The medium being cut and the HRC of individual knives tested will generally dictate which has better edge retention for the particular test.

M4 is famous for being tough but holding a great edge, and in the past has been the overall "best" of the tough steels.

REX-45 came along... its weaker than M4 overall in terms of enduring hard abuse, but stronger at the edge apex, which makes it better for normal "hard use" or volume use. REX-45 in part gets its "wear resistance" from being stronger at the apex.

CPM-4V I believe is tougher than M4 overall but also tough at the edge apex like REX-45, perhaps tougher.

Wear resistance through carbides is almost meaningless since most users of advanced steels tend to keep their edges crisp and sharp.

The wear resistance counts for nothing if your edge apex collapses. Think about the lone piece of sand embedded in the cardboard you're cutting. A grain of sand is substantially larger than the apex of your edge... when the two meet while cutting, it's similar in effect to a boulder falling on your leg.

I also rank CPM-4V as being overall superior to REX-45, CPM-M4, and Cru-wear.

Notable mentions include K390, 10V, and Maxamet. These all favor wear resistance more so than the previously mentioned steels, but lack in overall strength.

K390 however has an interesting dynamic that I've not fully wrapped my head around yet. In videos on YouTube, I've seen it endure things that you'd think it couldn't. Its Achilles heel, I think, would be a hard impact on the edge versus an unyielding surface.
 
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SubMicron SubMicron , might I ask what you base your assessments upon? You seem to speak very definitively since arriving here a few short months ago.

Collating various reports, personal testing, other? If I've missed your pedigree somewhere, my apologies. It's always good to know how much is opinion, conjecture, personal experience or demonstrated fact.

Thanks.
 
Blues said:
SubMicron SubMicron , might I ask what you base your assessments upon? You seem to speak very definitively since arriving here a few short months ago.

Collating various reports, personal testing, other? If I've missed your pedigree somewhere, my apologies. It's always good to know how much is opinion, conjecture, personal experience or demonstrated fact.

Thanks.
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First, as noted in other threads, I'm no more qualified than the next noob. However, to an extent, I have been accused by others of being an autodidact more than once and learning at a geometric rate, especially with complex dynamics.

I'm not trying to toot my own horn, but you did ask.

When I get mentally stuck on a subject, I'll stay stuck on it until I can figure it out.

Where I get my info:

I've literally watched every cut test video on YouTube, all of them, along with virtually every other related video I can find, the good ones more than a few times. Larrin's knife steel nerds website has gone a long way to providing insight and answers and his Patreon has a lot of good info too. This forum has been a wealth of info and I've lurked for longer than I've been a member. The same is true with the Spyderco forum.

With all kinds of wrong information out there, I have done some limited cut testing to prove/disprove various things and find a firm basis in reality.

Beyond that, what started it all, is my stubborn determination to use a knife at work. I'm in the furniture industry and the cardboard that's used is no joke. Its thick, dense, and very dirty. I'm sure some of it technically isnt cardboard. I'm not a "hard" user as I consider it, however I'm definitely a volume user with the amount cut in a typical day.

What I really want from this forum I'm not getting, except for once by Larrin when he called me out for being factually incorrect.

While I'm confident in what I believe to be true, I'm depending on people like you who've been around this industry longer to call me out when I'm wrong. I like debate and if I'm wrong I'm wrong. My ego isn't heavily invested.

I do however have the habit of speaking authoritatively, in which case, don't be shy... speak up if I'm wrong!!!

Fundamentally I'm here to learn and when I think I know what I'm talking about, I learn best through debate.
 
Well, I've been around these parts for a long time and have spent time among some of the great makers, both stock removal and at the forge. That said, my knowledge can be summarized on the back of a cocktail napkin, which is apropos considering that's where I was with a lot of those guys anyway. :p

I have lots of different steels in my collection of knives, custom and production, but its rare for them to take a beating, so I don't always get to see all that's under the hood.

The steel that sees the most use in my world is a small 3V fixed blade I've owned for many years, and which I can't kill...and my Austrian scythe that takes care of the wild yards surrounding my home in a heavily forested area.

If it wasn't for folks like those aforementioned makers, Larrin and Shawn, I'd be much further behind the 8 ball.

(I'm a bit of an autodidact myself, but not so much or extensively in the steel arena. Though I have more than passing familiarity. However, I am familiar with the personality flaw. ;))
 
Blues said:
I'm reminded of the Eagles song, "New Kid in Town":

"They will never forget you 'til somebody new comes along"
Click to expand...
For awhile I’d say Crucible was like the Lou Perlman of blade steels, today the trend seems to be going the way of nitrogen steels, a lot of those are European.

4V isn’t really new, it just didn’t get much attention until recently, the oldest knife I know of using it was a ZT that was made with Vanadis 4E, which is an analog.
 
John_0917 said:
For awhile I’d say Crucible was like the Lou Perlman of blade steels, today the trend seems to be going the way of nitrogen steels, a lot of those are European.

4V isn’t really new, it just didn’t get much attention until recently, the oldest knife I know of using it was a ZT that was made with Vanadis 4E, which is an analog.
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"New" is relative. It refers to the new "it", the new "hotness".
 
My satin finish yojimbo 2 BHQ exclusive jumped out of my hand after it bit me. Thank goodness it's M4. Brand new to boot. Sharpened away no problem. Long story short M4 is tough as nails.
 
Glad the tip survived! Saw a post recently (don't remember what knife) on Spyderco forums about someone dropping a new knife ....good portion of the tip broke off! :eek:
 
My experiences don’t completely agree with your 4v vs other tool steel assessment. I think 4v is a great steel, and at the hardness Spyderco runs it, the edge retention is decent. But I think the edge retention is not as good as k390 or m4 (my favorite). I also have seen very little corrosion or patina on it relative to k390 or m4.

I tend to cut mostly wood and cardboard, so your mileage may vary. My m4 knife is sharpened to ~15 degrees inclusive (by my guesstimate) so the edge geometry really favors my usage vs the basically stock hollow grind on my 4v knife. 4v is darned tough though... maybe I should thin it out to give it a fair shake.
 
soc_monki said:
Pic of the hole in the floor or it didn't happen! :D
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pcguy23 said:
LOL
but, I would like to see the damage to the floor as well!
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SubMicron said:
Tonight after work I'll check the floor with a flashlight and see if I can figure it out.
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This has to be the one. It's the correct size relative to how much white powder was on the tip. It's in the exact location the blade hit, and it looks fresh compared to what else is in the floor. It doesn't seem to come through in the photo, but with my eye I can make out a fine point in the hole.

Its completely unimpressive, which to me means the knife tip absorbed the energy of the impact which could explain why the knife bounced the way that it did.

It's right in front of the tip of my finger just above the shadow of my phone.

Screenshot_20200611-210906_Gallery.jpg
 
M. Johnwell said:
My experiences don’t completely agree with your 4v vs other tool steel assessment. I think 4v is a great steel, and at the hardness Spyderco runs it, the edge retention is decent. But I think the edge retention is not as good as k390 or m4 (my favorite). I also have seen very little corrosion or patina on it relative to k390 or m4.

I tend to cut mostly wood and cardboard, so your mileage may vary. My m4 knife is sharpened to ~15 degrees inclusive (by my guesstimate) so the edge geometry really favors my usage vs the basically stock hollow grind on my 4v knife. 4v is darned tough though... maybe I should thin it out to give it a fair shake.
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That’s interesting to hear it’s behind M4 on edge retention since it has similar vanadium, not surprised about K390 though since that has about 10% V.

I learned recently that the tungsten in HSS (like M4 and Rex 45) isn’t actually that big of a contributor to wear resistance since it forms larger, softer carbides than vanadium does. I wonder if 4V has only vanadium carbides or if it also has some molybdenum carbides as well?
 
M. Johnwell said:
My experiences don’t completely agree with your 4v vs other tool steel assessment. I think 4v is a great steel, and at the hardness Spyderco runs it, the edge retention is decent. But I think the edge retention is not as good as k390 or m4 (my favorite). I also have seen very little corrosion or patina on it relative to k390 or m4.

I tend to cut mostly wood and cardboard, so your mileage may vary. My m4 knife is sharpened to ~15 degrees inclusive (by my guesstimate) so the edge geometry really favors my usage vs the basically stock hollow grind on my 4v knife. 4v is darned tough though... maybe I should thin it out to give it a fair shake.
Click to expand...

I also believe K390 has better edge retention than the others mentioned, but less than Maxamet.

With the edge retention differences between M4 and 4V, the weeds get thick fast.

Without going there, how I understand the bottom line between the two is that 4V simply has higher strength at the apex. M4 is a brute at the apex too, but 4V will be stronger at the fine edge and will be more resistant to reflective spots on the apex.

Almost like having REX-45 but with the strength of M4 throughout.

With REX-45, its achieving its apex strength through high hardness augmented with Cobalt to prevent brittleness plus other perks. Its very strong, up to a certain level of course, and it can fail in a big way more easily than M4. What would be a big chip in REX-45 would be less significant in M4, generally I believe. REX-45 however will resist the small reflective spots on the apex better than M4.

With 4V, its achieving it's high apex strength differently than REX-45. I'm out of my depth on the reasons why.

In a blade breakage event, M4 possibly is slightly tougher than 4V. Larrin's toughness charts show that to be true. They also show 4V to be less wear resistant than M4 and I believe that to be accurate.

You're particular usage may favor the wear resistance aspects of edge retention more so than mine.

I keep my knives very sharp and with some of them, dont allow more than a few reflective spots on the apex, if any. It just drives me nuts and I like sharpening.

With that said, for my work knives, which have to be small, I do not like sharpening every day after 10-11 hours of working.

From that I'm drawn heavily towards steels with very high strength at the apex.
 
John_0917 said:
I learned recently that the tungsten in HSS (like M4 and Rex 45) isn’t actually that big of a contributor to wear resistance since it forms larger, softer carbides than vanadium does. I wonder if 4V has only vanadium carbides or if it also has some molybdenum carbides as well?
Click to expand...

I'd also like to learn more about the specifics of the hybrid carbide that forms from Tungsten and what else it does within the steel.

Here's the composition of 4V

Screenshot_20200611-224813_Knife Steel Compositions.jpg
 
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