K390 - The Best High Edge Retention Knife Steel?
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- Опубліковано 1 чер 2024
- I finally finished my testing of K390 so I can compare its properties to other popular knife steels.
Written version of this information: knifesteelnerds.com/2023/04/1...
Support future knife steel research on Patreon: / knifesteelnerds
00:00 Intro
00:05 K390 Composition and History
00:51 Hot Hardness
02:51 K390 in knives
03:18 Bohler's Claims about K390
03:48 Microstructure
05:24 CATRA Edge Retention
06:34 Toughness
08:03 Choosing Knives in K390 vs Similar Steels
08:25 Toughness vs Other Steels
09:17 The Biggest Problem with K390
09:38 Heat Treating K390
11:49 New Steel Ratings
12:57 Patreon
13:04 Knife Engineering
13:07 Subscribe
I have shared your videos with the younger Engineers at General Motors. Even if you aren’t interested in the knife aspect, the metallurgy discussion is first rate.
Thanks Larrin. You're work is so important for the knife community. This makes me want to try K390 or 10v!
20CV is a close relative
i did a K390 N690 SanMai.
For me the best of both worlds.
@@krustysurfer
It's not even remotely close. Lol.
@@CNYKnifeNerd i was under the conclusion that
M/K 390 20CV CP204 were in the same class of metallurgy formulas?
Please correct me if im wrong?
Thank you
@@krustysurfer M390 & K390 are completely different steels brother M390/20cv/204p are all similar steels in being good edge holders, K390 made by bohler, like M390, but K390 has amazing edge retention
This channel, the quality of knowledge and properly presented info is insane to only have 13k....
Applauding standing! I am an engineer buying my first knives, and I finally got all my questions answered with plenty graphs charts and words! Two thumbs up!
I love Cedric and Ada's videos and from their data K390 seemed like a good tradeoff of corrosion resistance for edge retention over M390. I got it in a PM2 and I love the slight patina it develops.
Lamination is the solution. Until Larrin gets around to making the high edge retention version of Magnacut he's talked about.
I would trust Larrin over the other guy any day and twice on Sundays
A higher vanadium magnacut for the edc market would be interesting. I think it would make sense and lots of people would buy it. The original would still be better for larger and fixed blades, but I think in the edc market, toughness is not as important.
I love k390. Easily my favorite steel. My edc knife is a spyderco stretch 2 in k390 that I adore- it's the fully ambidextrous PM2 that flies under the radar, and it's teal, my favorite color.
Been sad to have missed out on the BBB 15v sprint runs, though.
Thank you Larrin! This channel is Gold! Greetings from Austria, The home of k390 and m390
Yup, my K390 seems to stay sharp even when it looks dull. It’s magical. I love it.
The bell notifies a new subscriber video was just uploaded by sounding a new message alert.
Why in God's green earth do you not have more subscribers? You are a knife steel genius, and the master mind behind one of the best knife steels in existence. Thank you so much for sharing your knowledge with the rest of us. I am truly grateful.
That was the funniest call for subs and likes ever :D As always - thanks for the awesome information.
K390 is one of my favorite steels. I wish more manufacturers would start using it (given they can properly heat treat it of course).
No it should be MagnaCut mimimi
I've seen Reate using it (K390) on some of the knives like the Pena X series. And the new Reate made Boker Urban Barlow, but don't know if it's purely a Knife Center Exclusive thing or what. But hopefully, we see more companies start taking advantage of it. And so glad MagnaCut popping off and seems to become more and more available. As that steel is just amazing for what it is. With high scores in all corners of the holy trinity of the knife steel triangle (Toughness, Edge retention, and Stainless). S90V would also be nice to see more of instead of all the M390/20CV we have seen on everything for the last 5 years.
I agree wholeheartedly about MagnaCut. I think once some of the legacy manufacturers can wrap their heads around it they’ll more readily adapt to it. I’m pretty much over M390/20CV as I favor edge retention over corrosion resistance, but that’s just me, I still understand the overall appeal and own several knives in both. Give me MagnaCut, S90V, K390 or 15V and I’m definitely going to be more interested.
Spyderco Delica K390 is my favorite leather cutting knife, no constant stropping after long cuts. It is only .090 thick with a distal taper. When I do strop it I use mahogany plywood 1/8th thick by 1.25 inch wide by 8 inches long glued to a pine 1x3/4 handle with 1 micron heavy 50% diamond concentration paste. I clean it off once in awhile with Tap Magic cutting fluid I use on my sharpening stones except diamond stones I use water for.
Great steel!
Love my Police 4 Lightweight K390 🕷🕸
Omg babe wake up new KSN vid just dropped
Great video. Been rockin the police k390 for a couple years now.
I have carried the stretch 2 k390 for 1.5 years now every day. On the job and off. Its an absolute workhorse. I sharpen at 17dps with a tsprof and put a 30° micro bevel with a worksharp pocket sharpener ceramic after sharpening. I also use the ceramic on the pocket sharpener whenever i feel it getting dull. It only takes a couple passes before it cuts paper again. It is a workhorse. The ergonomics of the handle and geometry of the blade excel for work tasks. Buy one if you are actually going to use it, you wont be disappointed.
17 dps is 34 inclusive angle. Your 30 degree micro bevel comment makes no sense.
Great video! K390, S390 and M390 are all interesting, interesting how Bohler uses the 390 designation for top of the line products.
One you get to 400 things drop in performance such as 440C 420hc so you don't want to take a steel all the way up to 400s. Seems high 300s is the optimal number.
Larrin another home run. Great to support your UA-cam videos and Patreon. Keep us looking for more!
Man.. I’d love it if you did a series on the basics of heat treating and carbon steels.. explaining what’s happening at the atomic level
I’m just an enthusiast, but anecdotally, K390 has been incredible in my use. I even tried to cut metal banding by accident, and it barely rolled the edge where any other knife steel would have had the edge destroyed.
Thanks for the video. My Spyderco stretch in k390 is pretty much my all time favorite user knife that I own. I would love to see a video from you, dedicated to comparing the field of similar tool steels that are currently being used in production knives. K390 is sort of exclusive to Spyderco right now, but CPM-M4, CPM-REX45, HAP40(etc) all seem to be vying for a similar niche within the knife steel world. There’s all sorts of anecdotal reports and opinions on their individual attributes, but it would be nice to have an objective scientific analysis to reference. I have heard that M4 is known for being able to achieve the “scariest sharp edge” and REX45 is slightly more corrosion resistant. I would really love to hear your thoughts about these steels.
Damn, I always said I would never buy a spyderco but between Pete from Cedric and Ada and this video I may have to go back on that.
great info thank you.
Great video! So exciting!
Thanks for the insight. It's always a pleasure watching and learning with you.
Great video!
Thanks Larrin. Great Information!
Extremely informative. Thank you so much for all your meticulous work!
Great stuff Larrin
Good analysis!!
Thanks for this analysis.
Great job 👏 . Very informative. I love graphs 📊
Excellent!!!….thank you young man!
Hello Larrin (or Mr Thomas), i have only recently gotten interested in knives and what goes into making them, sharpening them, using them etc. While most of the things you talk about in your videos are still too complex for me to get a good grasp off, the things that I can actually understand are very interesting and a priceless piece of information. I ordered your book on knife engineering and am eagerly waiting for it to arrive. So i just wanted to thank you for the awesome work you put in and the great content that you put out for free! Im almost certain that my next order will be your latest book as im very much into history, I just wish I had found your channel sooner.
Thank you LARRIN. Great insights…
Thanks! I like how you explain this stuff.
You've got my support. I've been subscribed for a good while now. Thanks for the content.
Bought your book, great stuff! Thank you for your work! 👍🏻❤️
Thank You!
Enjoy these videos. Very informative and entertaining thanks, brother 💯👍
This is so nerdy great, I love it!
Great video. Hoping the algorithm blesses you.
Great stuff here, thank you thank you
Thank you for the awesome video on k390. I know Pete loves it.
Another outstanding video. It's a great service to the knife community that you provide, so that people can navigate the many steels available to them. I can't wait to read your latest book on steel.
Thank you very much, dear Sir!
I've just received your book. It's beefier than expected =) intimidating
Great stuff, Larrin! My K390 Delica is certainly amazing. Love your work!⚔🔥🙌
We couldn't agree more! Our most favorite steel since day one.
Thank you for validating my simping for 10v ❤.
(Also can't wait to see more about magnawear!!!)
I had the spyderco stretch 2 in k390 and it was a real performance blade. I wasnt really a huge fan of the design though. Id love to see Benchmade bugouts in more steels. I have an s30v bugout and ive used it so much at work, digging, prying, scraping, and its still perfect. I did put aftermarket aluminum scales on it for rigidity. Thanks for the video
I totally understand. Backlocks are so meh. But it’s better than liner locks and those gawdawful compression locks. Cue up the hate from the Spyderco junkies, but cutting away the scales right where the web of your hand goes when really bearing down on the knife is seriously stupid. It tells me Spyderco makes fidget toys for collectors, not real tools.
@@donrichter3523 Have you broken a knife or are you just venting for nothing ?
Where did you find aftermarket scales for the stretch?
@@donrichter3523my guy all of my spydercos with comp locks are the most comfortable knives i own lmfao, my liner locks are less comfortable in hand. the cutout for access to the lock literally fits the web of my hand better than a liner lock because the web isn’t at a parallel angle to the back, it curves down. the comp lock is also one of the strongest locks on the market rn, don’t know what you mean by fidget toys considering they make knives with ridiculously strong locks and super tough steels if you want it.
Thanks for the Video. So far I have had an excellent experience with K390, and I love the patina it gets after some use. Waiting on a puukko in K390 and can't wait to get it, considering getting another one in CPM 4V and a custom EDC knife in MagnaCut from the same maker. So far my only experience with MagnaCut has been with folders and I'm super excited to get a fixed blade in it. The only hard part is the wait, but well worth it once we get the knife in our hands 😅 Keep up the fantastic work
Highly recommended
What maker are you waiting on a puukko in k390 from. Also interested in fixed blade makers willing to work with high wear resistant steels that are ht'd for performance.
The PM2 in K390 is fantastic…only Maxamet , an alien steel is better…the newest (its 2023 with this comment) The big brown bear 10v heat treat collaboration is pretty close to Maxamet…but they are unattainable at this time…hopefully they (Spyderco) will continue to use it on other knives too in future….cost is steep…but for a lifetime edge retention knife its worth it…EXCELLENT channel and content too..thank you very much young man.👍👏👏🔪
I subbed buddy!
Great stuff brotha! Always love the insight you give. BTW, ever here of Assab PM60 steel? Picked up a knife that has that steel, but really haven't seen anything about it. Heard it may be similar to Vanax or Vanadis? No clue...
It is the same as Vanadis 60 and ASP 2060. It is a super high hardness 6% vanadium steel like Maxamet.
@@KnifeSteelNerds Thank you sir! Much appreciated!!
Awesome video!
Boehler recommends tempering around 550*C(1020*F). How is the toughness comparing to 150*C(300*F)?
I like K390 in everyday use, it is sticky sharp, and holds the edge for a long time. 15v is also excellent. 15v steel has great edge retention and no chipping issues.
Thanks for the data. : )
I was trying to listen too what was being said but was distracted by two dudes showering each other in sparks like R-Kelly with his golden showers😅😢
I totally xonwd out suring that as well. Good ol' Dudesons
Judging by the joke its safe to assume that the main audience is in the 30-50 range 😁 good one though!
Hot Hardness? Sounds like an adult video title 😅
“It’s the remix edition, of the song about pissin”
Another great video Larrin! So when will your stainless 10v hit the market? I know you’re thinking about it!!!😅
I love all my knives in K390, easier for me to sharpen than most of my stainless steel
knives (burr control is better) and holds a keep edge forever. I wonder if the high hot hardness is one of the reasons why it’s a standout in spyderco’s lineup as you are less likely to get a “burnt edge” on the factory edge than other steels. Stainless 10V with only vanadium carbides though… That’s a steel that would demolish the existing high end knife market…
What I was trying to say is I have both k390 And com 10v.thanx Larrin.they are both animals as stated.i super love that video
A Spyderco Endura in K390 is on my list to pick up soon. Ive also been wanting a knife in MagnaCut for some time, and in an incredible turn of events, for a Ritter Hogue Auto RSK at KnifeWorks for just $209. Shortly after ordering that, I found out Dekas were on sale for great prices at Blade HQ, so ordered a Wharnie for just $109 (deal of the century there). Cant wait to get my hands on tbat MagnaCut.
I got a native 5 salt in magnacut and its great 👍 👌 love it. 💯
The more research I do, the more about knife steels/ tool steels/ etc that I learn - the less & less I want a MagnaCut knife! All compromises considered, I'd much rather have M390/20CV or even S90V. Overall, they suit my use case better... but to each their own. It's something of an EDC renaissance right now, with the buyer being spoiled for good choices, in varying budgets!
so you DONT want a borderline rust proof steel with similar edge retention and toughness of 4v/cruwear
You need to do more research from Doctor Thomas @@acid6urns
I watched a video of a guy stabbing a cinderblock with a k390 police 4, seems pretty tough
Yes bliiies more KSN
Greetings from the north of Spain on the other side of the pond.
Very interesting content about K390 and its behavior.
Do you plan to translate your book into other languages in the future?
Probably not
Thank you for your work, you're the best! I'd want to ask you about S390 steel. I have a knife made out of it, but I cannot find any details or information about it. Is it comparable to K390? Or maybe they differ?
Keep up the good work, Champ!
www.bladeforums.com/threads/s390-steel.1958293/#post-22300282
I have delica and endura k390 and they strip up nicely.and I spray them down with plant based antitrust oil
How do you feel about zmax? I feel like k390 is about the upper limit for usability in high resistance blade steel. How much would laminating something like 15v or maxamet with aebl make that a more viable option?
I have been very impressed with k390 & Rex 45
Great video! I’ve been enjoying my k390 knives so far. I have a cpm-15v PM2 now that I’m putting through it’s paces. Have you played with K490?
I have not been able to obtain any K490.
@@KnifeSteelNerds I would be excited to hear your thoughts if and when you do get some to test. The data sheet makes it sound like M4 on steroids! The only knife I know of that is commercially available in that steel is the Lionsteel T6?
It is designed to compete with Vanadis 4 Extra and CPM-4V.
Don’t just hate them left over carbides! Great vid.
Where does MOVA-58 fit in the knife steel chart? Is it any good? All I can tell is that it’s stainless.
Is there any explanation on this steel?
Hey Larrin, Where can I find a fifth quality of steel: durability in heat. So I dont have to worry about stabbing a piece of meat in the bbq (lol - I jest but that's an example) I guess you refer to this as hot hardness, but are there other nuances? hot toughness, hot corrosion resistance? I'm asking
Do you know of any resource that catalogs the hot hardness of different steel types? I'm a budding knife maker and very wary of temperature changes during final grinding.
High speed steels would be a good place to start
Nerd ? More like Guru. Thank you for your research.
I was just looking at the data sheet from bohler and im curious why you chose 400 for tempering when the data sheet shows between 930f ans 1020f as ideal ranges for secondary hardening?
Most likely would be a huge benefit in smaller slicing knives. Bringing out harder carbide's. Granted it comes with some Con's due to that.
"Secondary hardening" does not improve wear resistance, that is a common misconception. The tiny carbides formed in secondary hardening don't contribute significantly to wear resistance. In my big CATRA study I compared 400 and 1000°F tempering of CPM-4V and found no difference. In tests of toughness, however, several steels I have compared showed a sizable improvement by tempering at 400 instead of 1000°F.
@@KnifeSteelNerds I feel like thats just not completely true based off of science gate PDFs for some steels that ive been reading. But hey what do I know.
Uddeholm also found no wear resistance difference in their testing of Vanadis 4 Extra. But if you want to link some articles we can discuss them. See slide 33 for the V4E data: thecbm.co.uk/wp-content/uploads/2015/11/Tool-and-die-life-2-March-2016-Uddeholm-Tool-steel-selection-for-AHSS.pdf
Great video. Perhaps I’d get a 10V knife if offered in something I wanted. And that’s why the interest in K390, since it’s the upscale steel choice for the Seki City Spydercos, yet nothing really in 10V or Vanadis 8. I currently have a Endura which I like, but I love the Delica Wharncliffe in K390. What a fantastic box cutter! I’m generally not a huge fan of Spyderco because of their business model of sprint runs and exclusives, the oftentimes wonky ergos, and frankly dislike most all of their locks. But the Delica Wharncliffe in K390 makes me not care it has a meh backlock and it breaks down boxes like few knives can.
if you want 10v, bladehq has kizer fixed blade exclusives in it.
also on the spydercos, i’ve found that all of my USA made ones have excellent ergonomics. now my seki knives definitely suffer on the end of ergonomics. the manix 2 and pm2 especially to me have awesome ergonomics.
Can you guys test and make sm100
Not related - I have a Lionsteel M4 in magnacut and it is blowing my mind!!!
It is magic!
I'm just being torn. I want to try it. But I'm casual user. I do food prep on picnics and business trips using my folder knives in 99% of tasks. And I'm bit afraid of K390 being not rust resistant. Tempting and alarming at the same time.
That's a legit concern, while ive used K390 a lot i only keep it oiled and in storage for days i break down dry material. I carry stainless mid and supers much more often.
@@thaknobodi heh couldn't wait more and ordered one just yesterday. A small present for myself i could not resist. So i'm exited to get my Police 4 K390 in a few days. I had some experience with hight carbon kitchen knifes and had no problem with them as i am a carful user. But this will be my first folding knife in non rust resistant steel.
Properly treated k390 is actually more corrosion resistant than one would think based on the stats, and it slowly develops a golden-ish patina over time. As long as you clean it regularly, and perhaps oil it if using it in a high salt/acidic environment it will be fine.
@@MB-jg4tr so ive been using an endura k390 for the past month and a half and there is only the slightest greying visible in certain lighting, growing off the edge from cutting a couple limes then washing it shortly after. No discoloration on the spydie hole or anything. I do put vaseline on it regularly though
What influence does 0.55 Si and 0.40 Mn have on this steel?
May the force be with you!
Hi Larin. I heard a knife company (Kunwu) is investigating doing one or more knives in "S390". Any idea what that is?
www.bladeforums.com/threads/s390-steel.1958293/#post-22300282
What if the quenching plates are submerged in liquid nitrogen and you are doing quenching with cryo treated plates?
Hi Larrin.
I wandern if a laminated K390 whit N690 steel whil increase the toughness of a final blade.
A knife manufactur says: ,,We’re using a laminate steel because such a steel is at least 20 % stronger than a solid stainless steel." (VG10 core laminated whit 420J2 steel)
Knowing that N690 hawe a poor toughness, makes any sense of laminating K390 whit N690 steel ?
So if a particular steel is composed in such a way to have high red hardness would that mean it's less susceptible to the so-called burnt edge phenomenon?
Yes
Maybe in theory, but I got a police 4 recently and it was definitely burnt, grind was all over the place too, for seki I mean, started to stabilise after about the third sharpening, before that and especially in the belly it was rolling very easily at 14 and 15 degrees. Sharpened both by hand and on blitz...
@@8thsinner I have a k390 dragonfly that had the same issue. It had a really burnt edge with a lot of belt chatter. It took 3-4 sharpenings to fix but it's great now. The Seki knives seem to have this issue more than Taichung and Golden
@@stickyedge7113 I agree and it's a recent thing too, my older zdp seki was very symmetrical, very sharp, and I can't remember but I don't think it was burnt either.
Maybe it's a change in processes, or staff, or the differences between old and new belts but it does seem more and more that grinds are coming out uneven and burnt for more and more people.
Easiest way to get rid of it is take it to around 15° then to 20, then to what ever you want it at. Then you'll be rid of the burnt up edge. Or just use it and sharpen it as needed. Either way will get you there.
love k390
I prefer Vanadis 4 Extra to any other steel. Also,because its all about heat tr. And geometry,I'd take a ballbearing steel for my fixed blade and Victorinox SAK steel for my folderretf I get high toughness and stain resistance, doesnt matter much, how good is the edge retentionn
Silly question please, I understand you have a blog site. I've never really used them before so how do I access this site. Thank you from an old vet.
knifesteelnerds.com/
Awesome write up, I've wanted to try some K390 for a while and its pretty hard to get hold of. But I can sometimes see myself getting a bit of 10V and not really losing much out on in the edge retention party at the end. There's definitely some uses for these steels in certain cutting tools though and they do seem to produce some exceptional results there.
Not sure I want to get anything more than a 240grit belt finish though :)
Here's your knife, its uglier than a dropped pie, but it probably won't get dull either.
Gobec currently has bars in stock. 👍
@@ryanguldbrandsen7672 Thank you, now I just have to conjure up enough German to muddle through there. :)
Its down on a list though, I'm yet to get some ApexUltra and Magnacut to try out and there's a local place with a big 1.05m length of 10V on sale at the moment with free delivery so I think that might be where my money will be going in the near future.
@@krissteel4074 Plenty of time to try them all out. 10v is more of a specialty steel. It will rust on you if you don't take care of it. Magnacut is a great edc steel that you don't need to worry about. I have many many many knives in magnacut. My most used k390 is a wharncliff dragonfly. I use it as a permanent at home Amazon package opener. Probably will never need to sharpen it. 😂😅
@@krissteel4074 also, google translate should take care of all of that for you. It was easy to get 2 bars from them.
240 is ambitious in my book. 180 is as high as I'm doing. A broken in 80 is fine lol. High vanadium steels don't grind or polish or take surface finishes the same way your mommas chromium steels do.
Does the mean that I have to ditch my magnacut folder for a k390 folder ?
A question for everyone with K390, i live near a beach, and for that reason i use H1, but since the edge retention is really bad i would like to try K390, the question is, how is the corrosion of this steel?, it would be use for EDC, so it will be expose to sweat and salty breeze everyday, thanks in advance
I have Endura 4 on k390.
Even tap water can make rust to the blade, atleast on pivot area, were it's difficult to dry. I have noticed this when I have washed the knife under tap water and could not dry the pivot area properly. But it's surface rust, which I don't mind really.
I have not used it on salt water, but you can be sure it can make rust to the blade.
I always rinse and wipe the blade dry after foodprep for example, so the edge stays sharp. And if you wipe the blade dry after use, it doesn't rust. I have made patina to the blade on purpose thought, by leaving some food (citrus fruit/mustard) to it without wiping it.
Sweat is also salty, so it makes surface rust and patina to the blade.
So conclusion, I think k390 is steel that you want to keep dry.
I have some photos of the blade and some disassemble photos on my instagram (sak21spartan). Ask more if you like!
Youd be better off with S110V. Same edge retention as K399, but a 9/10 corrosion resistance. A lot harder to sharpen, though. Honestly any steel holds an edge better than H1, LC200N is about AUS-8 in edge retention but 100% rust proof like H1, just more expensive than H1. I have two spydercos in LC200N as my wet work/ kitchen knives
What about s390, I was just curious if other company's like CTS or crucible have a comparable steel to bohlers s390?
S390 is a high speed steel with ~5% vanadium in it. Other steels with roughly similar properties would be CPM-T15, Z-Max, CPM Rex 86, and Maxamet.
What would you say the optimum HRC is for s390? I have a custom with s390 at 67hrc.
Subscribed because you said you need more subscribers😂😂😂(not really).
Great channel for steel conoiseurs.
Some resting like cut test to see real edge retention would be aporeciated.
Some store like BladeHQ should give you affiliate links with knives of these steels for sure.
My spidy rusts is hard to sharpen and looses edge pretty quickly , i duno whats the hype all about Kinda miss my 180$ tbh ps stupid plastic handles and grandpas back lock
FYI, clicking the bell enables the viewer to see when a new video is posted, thereby increasing traffic to your channel.
I am curious if this is a good hot hardness steel why you didn't temper at 6-700 in at least one coupon to collect at least some data on that?
I can't say for sure but I doubt seki city is using the bohler recommended spec and I suspect they are secondary tempering hotter which is what gives it the advantage over golden tempering.???
Do you have any plans to test this aspect for us or yourself even?
600-700 would be an odd choice, whether we are talking Fahrenheit or Celsius.
@@KnifeSteelNerds Well I don't know what temps are used for high second tempering, so educate me there if you please. Either way I want the data for the best potential edges because I would like to try making some from it.
The Bohler datasheet recommends 1020°F.
@@KnifeSteelNerds Oh, okay, thanks
A couple of those charts hurt my eyes! ~ LoL