How do these stack?

Here is a comparison of these popular PM tool steels in production folders.
Special thanks to Darby for letting me borrow his Cruwear Millie for so long.
I'm missing the 4v but I owned one in the past and currently make knives from it. In a production knife from spyderco it will be softer in hardness than the Rex45 but may out cut rex 45 if the 4v is at sufficient hardness due to having the advantage with slightly more carbide volume and more harder Vanadium Carbides, yet similar Strength and stability, yet on the softer thicker end may have more obtainable raw toughness at lower hardness depending on HT and Geometry.
Here is M4 vs Rex45
• CPM REX 45 | Edge Toug...
M4 vs K390
• Spyderco Edge Stabilit...
More M4 vs K390
• Spyderco Police 4 K390...

[@BillKayNJ]

I was working in a warehouse, cutting open a box. Someone bumped me with a bmcase of bone in pork loins (80-90 lbs) which caused my knife (Manix 2 Cruwear) to come out of the box I was cutting and blast a low carbon steel pallet rack. All I had was some slight rolling and blunting. The primary bevel (cutting edge) was sunk halfway up to the secondary, and I was able to straighten it out with a butchers steel. Stats were around .035 BTE, sharpened by hand on dmt coarse and a fresh fine then stropped with a 1 micron. Likely sat around 12°-15° dps. I Love Cruwear but I am looking forward to getting my hands on a ZDP as a dedicated slicer. I honestly feel that due to the hardness, REX45 may have failed, in this particular instance.

[@FearNoSteel]

Fucking cerebral, love this. That's an educated user right here.

[@chrisf572]

I have a ZDP stretch 2. It’s really impressed me. I have it sharpened at around 15 degrees with a mirror polished slightly convex edge. I was putting up paneling in my garage and while I was cutting out for an outlet I cut through the paneling and dug a nice groove in the concrete floor with the first eighth inch of the tip.

[@chrisf572]

The damage was very minimal and easily fixed. About 5 minutes on the DMT EEF and a quick strop and it was back to whittling hair

[@nOObels1]

I really want a dedicated slicer that I can use a lil harder if needed, so rex45 is tge way to go?!

[@mikelikesknives428]

Thank you for an easy to understand explanation. You do that very well. I have to watch these more than once to make sure I got it all. Thank you again!

[@FearNoSteel]

Thanks, yea just off the cuff, sharing my experience.

[@Outpost_76]

Awesome video, I hope this clears some things up for guys. I need to get my 5 way Cruwear comparison video done so it will show just how much it differs from knife to knife even all being Spyderco. Keep up the great info brother.

[@FearNoSteel]

Thanks Gerald, Keep up the strong work on testing.

[@thomasschowalter8475]

Thank you for making this. Helps put things in perspective and make more sense.

[@zachstuff]

Thank you for sharing another lesson in knife knowledge with us! I always like pictures! 🤙🏼

[@Cody73]

Thanks for the amazing info as always Shawn. There have been a few confusions about Rex45 and this addresses them all.

[@FearNoSteel]

Thanks Cody.

[@anthonywaldrep5982]

Awesome explanation and beautiful cutting board!

[@kevinfitz3721]

Great video man! Thanks for the info and content I appreciate it.

[@concealmenttraining9371]

Great explanation... thank you.

[@alalbert907]

Awesome way to explain Thanks

[@jayballard9944]

Awesome video...very informative...thank you!

[@Chriscueva]

Rex 45 seems badass

[@abc456f]

Great information, thanks!

[@Gpknives]

Great break down. Looks like that Shaman has seen some serious work/re-profiling. =)

[@knifetimestory]

Excellent breakdown. Wish MAXAMET had been in the mix, but this is still very helpful. Thank you.

[@glockgaston2922]

Thanks for the knowledge homie!!👊👊👊

[@FearNoSteel]

No prob, thanks for joining.

[@johnmaher4431]

Great video!

[@tomhosangoutdoors9380]

Great video buddy!

[@FearNoSteel]

Thanks Tom, yea use that bitch up, drop the angles a little on it and have fun.

[@gway9226]

I'd love to see you And larrin talk about rex 45. Different thoughts it seems

[@mickkeim4142]

Thanks Mr. Bear...that helps a little.

[@FearNoSteel]

Itty bitty bit

[@justinkase1360]

Very helpful video. I picked up a Rex45 as a first knife. Did you do a video about your regrind? I need to pick up some sharpening supplies...

[@jcoolG192]

That was awesome! Thank you!

[@FearNoSteel]

Thanks Kurt, can be difficult to do a video like this with all the shit swirling around in my head and liking to have all the information to back everthing up but I just haven't found the time to edit everthing together and just needed lay it out for regular folks somewhat. I'm hoping to edit some content together but I've been too busy sanding, grinding and doing research and QC on my work.

[@jcoolG192]

@@FearNoSteel when you do this in 7 1/2 minutes...I don't need Google! 😁 Thanks again Shawn!

[@swiggamortis5521]

Crackin eggs of knowledge.

[@revolvermaster4939]

Damn I learn a lot from you!

[@jodyrowe8166]

Good shit man.

[@knickly]

One of the things I've come across a lot (in other fields) are studies that measure the suitability of "proxy measurements". In other words, evaluating whether an existing testing method actually tells you what you need to know. I think for a long time, people in the knife community have made a lot of assumptions about how tests/properties match up to knife performance - for example, Charpy toughness and abrasion resistance. I think perhaps we're finally on the edge of a golden age in which some really talented, generous people are questioning, evaluating, and challenging this assumptions.

[@matusknives]

Every single knife enthusiast should watch this and if it does not make sense to him, then just spend a few evenings reading the Knife Steel Nerds blog. This is material science, it is OK if it does not sound intuitive right from the start.

[@bobhabsolute4995]

Hi, I like big whittler as my hobby is spoon carving and I would like to know which Big Spyderco would be best. I’m looking at the Police 4 either the hap40 or the FRN K390 or the Native Chief REX 45. The Endura in K390 is interesting as well. What I like is a 3.5’’ blade with a nice tip and I carved seasoned wood as much as greenwood. I have plenty of fixed blade whittler (roughing with a V4e blade and finishing with a 14c28n and a tool roll for planned excursion) but I want a folder as my on the go whittler. I already have a Super Freek but the tip is too big for the curves of the spoon neck. I am open to all suggestions and I have DMT plates to sharpen any of these knives. Based on your videos, I would pick the Native but I am all confused because you are so good with ht that I am now wondering if I should go for steel like Maxamet or S110. Please, help me.

[@jacknemo8021]

I agree. Got the K390 and 10v. Prefer the K390 even though the 10v seems to last fractionally longer. The K390 just seems like a nicer (smoother?) edge at higher grits. No idea, I'm not a metallurgist, it just seems like that's what happens .

[@JimiJamesIII]

Thank you for the excellent information. All these steel arguments, with the many variables in play, I don’t see any way to really say one is better or best or whatever. Every knife is different as is every user. One man’s junk....,

[@tywiggins13]

Amazing

[@Bob-od5ut]

You talked about it a bit but i was wondering if i could get away with sharpening rex45(or m390/s90v) with the cosera stones. i have an atoma 400, chosera 800 and 3k and 1micon diamond strop and i am thinking about getting some higher end steels.

[@harlanadams5176]

I dont subscribe to many channels but you know your shit and (after watching alot of your videos) I value your opinion.. I'm looking for a new kick ass edc; I currently looking to retire my schempp tuff (3v) which I've been happy with.. what would you pick for edc/wood cutting tasks- k390- rex45- s110v or maxamet? Or would choose another steel?

[@bele28]

GREAT VIDEO! Thx for sharing your experience with these steels. I just picked up native in maxamet and love it.. I feel like this is what I always wanted from a steel.. would loove to have some k390 tho.. and maybe a beefyer knife in rex45 :D

[@FearNoSteel]

Killer, thanks for sharing. BBB

[@PaulK390S90V]

Surprised in the s30v over the cruwear...such a cool name you would think cruwear would be top dog lolol

[@anthonycampos7417]

I know it's a moving target full of nuance but would you place S90V above Rex 45 given all the same parameters including HRC and Edge Geometry? Or would it be on par?

[@steeltoez8345]

I purposely sharpened my rex45 like a tard just to see how it performs. Really notice a difference after several edges are put on there and come to a conclusion what does the job the best. Doesn't feel fatigued at all but there is nothing else to compare it to. Low edge retention and jagged cutting quality in my opinion are symptoms of fatigued steel. Next edge will be used with more appropriate abrasives. The knife tested at 66 hrc and the carbide volume seems moderate so I feel it's a good test bed to try out things. I'm not exactly counting the inches of cut material but I do feel the edge has held up better than it should have. Cool collection btw.

[@Tedvaard]

Awesome video, man. I have the Rex45 military and it has performed really well for me. Just to clarify what you said about the abrasives: If I sharpen this on something like a DC4 or CC4, or even Japanese water stones, I could weaken or fatigue the edge vs using diamond abrasives? I also use bark river black/white compounds on my strop. I don’t mind it taking a while to sharpen, I just want to make sure I am not inadvertently dork ing with the awesome edge stability that Rex45 provides.

[@FearNoSteel]

At the end of the day you can do whatever you want. It's not that you can't get the knife sharp without diamond /CBN. It's that your leaving some performance on the table without with steels +60rc and +3% Vanadium and plus 0.8% carbon. There are different combinations you can use for sure. You can cut the apex in on a dull knife with the diamond and than burnish it with the brown/grey ceramic which will create less fatigue. However, best practice is to use diamond/CBN throughout for crisper, healthier edges less prone to failure. Here's the analogy, Why waste money on a car that has more performance If you only use a fuel that doesn't allow the engine to perform? Ceramic on a steel like CPM 15v at 67hrc you'll be confused why the performance is lower if you don't believe that diamond/CBN is important for these kinds of steels and HTs just like putting shit fuel in a Lamborghini.

[@Tedvaard]

Ok, gotcha. Thanks for the reply. I have diamond plates from the worksharp, I just haven’t used ‘em much yet. I’m guessing those should work. I bought it after watching you use it to sharpen s110v. I’ll start with those and look into getting some diamond spray and a new strop.

[@coffeltk]

How do you find s110v does with chipping/toughness?

[@christopherrodriguez4391]

How much would it cost for a Rex 45 native 5 regrind?

[@OTG414]

Is there a general rule of thumb that someone can use to determine optimal edge angle for different kinds of steel? Or does the grind geometry have too much of a part to play in determining this regardless of the type of steel?

[@randykurtz1994]

We’re would 10V fit in? Thanks!

[@nintendontbutdo5507]

What are the models of spydercos he is showing on here? Three of them look like a cross between a para and a resilience

[@kevinAuman1]

Bro, I laid the edge back just a little on my rex mani2 and the edge crumbled just cutting paper and I could easily lay a bur by rubbing it on my pant leg even after stropping but funny enough even tho I felt the tiny chips after cutting soft materials I cut an aluminum can in half and it didn't dull it one bit??? Has me stumped i sharpened on venev stropped with Ken schwartz 1mic spray on kangaroo 🤷‍♂️ i wonder if I just rolled the burr back and forth too much without knocking it off weakening the apex

[@BillKayNJ]

Where do you find the current "sweet spot" for EDC alloys? I am currently happy with 4V/V4E, K390, and 10V. For a tougher alloy, I tend to go with M4 or 4V. While I do have a custom B&T in REX 76, I don't use it... It is ground Way too thick for my tastes (.050 BTE at the heel and tip, .040 at the belly). It was made by someone that is fairly popular on Bladeforums and in the knife community as well as on here, so I do not wish to drag his name through the mud over one knife. It was probably an oversight, and it happens... That being said, what do you think I should expect from REX76, as far as plastic deformation, edge retention, and If it does get over loaded laterally, would I see smaller conical blowouts or larger fractures?

[@FearNoSteel]

Depends on the user not the steel. If a guy is using his knives like a knives to cut cuttable materials and knows how to sharpen can fuck with anything he wants. I'd rock 15v, Rex 121, s125v so I can sharpen when I want to not because I have to. Some people just need 420hc, soft and thick so they can burnish it to death with honing on soft materials so it stays nice and dull so it can never chip when being used as a toliet wand. So it's difficult to pin point a sweet spot if we'll talking universal generality. We'd have to check some boxes and rule em out.

[@Crushenator500]

I'm literally debating between getting the k390 police or not right now. Very timely.

[@Oozy9Millimeetah]

Get it, -probably- my favorite folder, takes an amazing edge good geometry elegant as fu....

[@Crushenator500]

Oozy9Millimeetah Just put in my order last night. I’ve wanted it for a while, and the discontinued status and current sale finally swayed me. I was debating between it versus the Millie for the longest time, Spyderco made the decision for me!

[@johnm.runyon3682]

Crushenator500 k390 PM2 is being released by bento box shop in a few days.

[@speedwolf5212]

Enlightening video as always amigo!. How would you describe “wear resistance” vs “edge retention”? I feel like those 2 factors often get confused. I used to think “wear resistance” was the ability to keep the edge when cutting more abrasive material but I’m starting to think that might not be accurate.

[@FearNoSteel]

In controlled cut testing wear resistance is a HUGE factor. In real world it depends on the user, use, and the edge Geometry. How it was sharpened is also HUGE Abrasive type and bonding, finish and if the burr is removed and well apexed without crushing the point. I feel strongly about using high wear resistant steels because they simply cut longer for my designs and uses. If I made different designs for different uses and users I'd probably prefer something else. So there is some wiggle room for folks that argue one being better than the other in real world. Yet the fact is in controlled testing higher wear steels will cut longer unless sharpened and processed like shit.

[@kao9379]

K390 is my favorite steel. Feels like a friend😂 Don’t know how else to say it.

[@NK-wy8wp]

Just purchased Para 3 K390.. 😁

[@seanleau]

Hi Sean, where does m390 and zdp189 fit in there. Those are my favourite steel.

[@FearNoSteel]

Around M4 and Rex45

[@seanleau]

@@FearNoSteel thanks

[@nintendontbutdo5507]

What are the models of spydercos he is showing on here?

[@krispybeats6615]

Found this link on spyderco forums Glad i got the police on the seconds sale 🤣 i was super lucky i think 🤣 This new frn police is a bit less hrc? Im a noob at this stuff, but im learning 😁 thanks for sharing knowledge dude 👊 comments are preety informative as well 💪

[@arn6376]

Where would S90V fit into these?

[@Colbbee]

I broke the budget picking up all 3 Rex 45's...no regrets (except for the orange scales). I just recently picked up a 4V Shaman, which is my first experience with the Shaman or 4V...do you have an opinion about how Spyderco treats their 4V or where it lines up in this matrix (toughness/wear resistance)? Thanks Shawn

[@FearNoSteel]

I put that in the description, I was surprised at the hardness values Spyderco was pushing. No one would have known if it wasn't for Kurt's (jcool) work hardness testing peoples knives. Check out his KZbin.

[@kevinfitz3721]

@@FearNoSteel what's his KZbin I cant find it

[@FearNoSteel]

@@kevinfitz3721 he's here in the comments "jcoolg19" look for the Snoopy

[@kevinfitz3721]

@@FearNoSteel thanks!

[@southerncross100]

The Cru-Wear is popular at the moment on the Spyderco Forum.

[@FearNoSteel]

Cruwear shaman looks dope.

[@southerncross100]

I still have the Malanika puukko in Cru-Wear that you had heat treated at Peters and sent over to Daniel for him to make a puukko out of. Doesn't hold its edge as long as the 4V version you organised, but it sharpens easier.👍

[@abc456f]

I have two manix 2's in cruwear, a cf and a smooth g10. Like it a lot. Also a fan of m4 in the Benchmade superfreek.

[@FearNoSteel]

@@southerncross100 yea that is interesting eh? At the time, it wasn't really known if Cruwear would out cut 4v with my knowledge back than. I really liked how it sharpened so it had to be done.

[@dark_gravity_edc]

Unless it splits uranium atoms it's not truly hard. Lol Thanks for the video and knowledge you're spreading.

[@krispybeats6615]

Maxamet beats all this a? Manix2 69hrc?

[@revolvermaster4939]

If I understand you correctly, diamond is better than ceramics for harder steels as ceramics may cause fatigue due to “overworking” the carbides?

[@FearNoSteel]

Vanadium Carbide hardness is ~87hrc, "Ceramic" is ~79hrc. When you sharpen a hard steel ( +60hrc) with lots of vanadium carbides with softer ceramic abrasives, it makes the edge more prone to failure in use, The ceramic cuts the matrix around the carbides fine but since the vanadium carbides are harder they are being cracked and strained due to burnishing. One can still get a sharp edge with ceramic by breaking and burnishing the all the microconstituents in the apex to a finer radius but the edge has less stability. Todd Simpson shows the matrix supporting the carbides is eroded and seems the carbides are more strained. Keep in mind I'm talking about a high level of sharpness and performance I'm not talking about sharp enough or good enough, most folks don't care about the details unfortunately. However, if they want to complain about lower edge stability they don't get that right if they're using the wrong abrasive.

[@FearNoSteel]

There are different kinds of carbides, the hardest carbides are vanadium carbides. Generally speaking, the more of vanadium In the steel, the more of vanadium carbides. Softer carbides like iron carbides and chromium carbides can be sharpened with ceramic without issue.

[@revolvermaster4939]

@@FearNoSteel Thanks for the EXCELLENT explanation and educating me. I learned pretty quick that Arkansas and Norton stones are pretty much worthless on high speed tool steels. They’re all relegated to shovels and wood chisels now cuz I replaced em with diamond stones and diamond spray strops since I started watching your productions. I like my shit scary sharp and the harder steels are new to me. I was thinking about ceramic stones , since I never used any, until I heard you mention the metal fatigue and I wanted to make sure I was headed in the right direction. I haven’t found that any of the so called hard to sharpen steels are any problem at all with the diamonds. I’ll be drinking my beer in your honor tonight!

[@FearNoSteel]

That's what I like to fucking hear, cheers

[@IRMalcolm]

Would a dmt rough stone fatigue the edge for s110v?

[@FearNoSteel]

Hrrrm? No, that's Diamond Abrasive and s110v is like 60-62rc. That's not how fatigue works

[@IRMalcolm]

@@FearNoSteel Thanks, I'm bad at sharpening and scared to touch the edge on my pm2

[@the_sharp_carpenter]

We all wanna see the purple regrind lol

[@FearNoSteel]

She got old, thick and ugly. Used hard and put away wet.

[@RealAndyOriginal]

alot of science for opening amazon prime boxes.

[@00YahSun]

How much u want for the Cru-Wear model?

[@FearNoSteel]

Not mine Mos, It's my friends. He let me borrow it for testing and I'm doing a Regrind on it.

[@bp-hx9ts]

Big Brown Bear but how much does your friend want for it lol

[@13Hangfire]

BBB, you know I'm gonna ask why you don't have the ZDP-189?!?

[@jimmycricket7946]

U think 4v is better then all the steel's you have on the table?? Generally speaking nothing specific.

[@MsKatiepeter]

Hot rod grind that k390 police while you're at it!

[@justinpatrickhoffman]

Thank you for admitting you can never point your finger at any 1 thing. Many people get tunnel vision and over simplify a multitude of factors.

[@lionknives3]

How are you BBB!

[@FearNoSteel]

Doin good my man 👌

[@JustPorcupines]

If M4 and Rex were both given a polished edge, doesn't Rex perform better, due to the finer grain structure?

[@FearNoSteel]

That's a great question, My experience says yes. Keep in mind I haven't done any controlled testing to prove beyond a shadow of doubt to everyone. However I feel strongly enough with my personal testing, anecdotal use and experience to put this into practice with my custom work. That's why I use so many different steels. They seem to have synergy with different edge finishes, but I don't have conclusive evidence so I keep this information between friends.

[@JustPorcupines]

@@FearNoSteel very cool. Maybe I'll test the idea myself, for some firsthand data. Rex has been awesome so far, and I expect to start seeing dealer exclusives in this steel coming out within the next year. I just hope a Rex 45 Military exclusive drops soon, to give my sprint Military a friend. Thanks for the info, even if it is anecdotal, it's still useful.

[@stefanwolf88]

Where would you put ZDP 189 in this list?

[@FearNoSteel]

In a spyderco, it's in the range of M4. They run em softer. I have a few kitchen knives in ZDP, they run harder. I enjoy the steel when ran hard. I Look forward to using with my custom work.

[@leotam3372]

@@FearNoSteel is it softer because of the clad?

[@FearNoSteel]

@@leotam3372 HT

[@John..18]

Sorry,,, the S110v, is for me, because it's stainless,, just my 2 cents..

[@StoneHands25]

I though rex45 was tougher than k390

[@MrCrazyclown145]

Man i knew i was missing out when i passes up the rex...

[@FearNoSteel]

They'll make more I'm sure. It's a favorite.

[@johnm.runyon3682]

colin Ingalls shaman in Rex is coming

[@MrCrazyclown145]

I sure hope it does

[@dombond6515]

Dude everytime we get a cool new steel people start to hate. Rex 45 with a jacked hrc sucks bro! Is a knock off m4 its all hype. Dude people have been begging for a high hardness good wear resistance and and decently tough steel. Glad u did this because we want cool new shit like this! And not supporting the new cool shit will make companys think eh, let's just do m4 or better yet s30. Smh

[@FearNoSteel]

M4 is dead to me. Hurts, was my first love but better shit is available. It's 2019. People only know what they know and haven't gotten a chance to play with everything.

[@mitch858]

Just buy maxamet and dont sweat all the options

[@revolvermaster4939]

I chipped up a manix LW maxamet with light use cutting natural fiber rope and woven polypropylene sacks, but it was the factory edge and seems much tougher since I sharpened the chips out.

[@bobnery]

So silly, all this hypothesizing to open some Amazon boxes

[@FearNoSteel]

I still got my view and a comment, so I'm happy. Got 'em

[@neroknives1828]

To soft

[@FearNoSteel]

Im too poor to put the sebenza here in the line up at the bottom xD .

[@neroknives1828]

@@FearNoSteel atleast it'll still be cutting like the first day, when your spyderco will be .030 bte

[@neroknives1828]

@@FearNoSteel you have a high hrc knife you can't take advantage of its stability. Thanks for the effort spyderco 👊

[@neroknives1828]

@@FearNoSteel take back the sebenza comment. Im still triggered

[@FearNoSteel]

@@neroknives1828 hahaha I love you

[@neroknives1828]

To thick

[@FearNoSteel]

Wish I had the money to put a Hinderer at the bottom.

[@nintendontbutdo5507]

What are the models of spydercos he is showing on here?