Talking Steel: CPM-Rex 45 (The Best EDC Steel)
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- เผยแพร่เมื่อ 30 มิ.ย. 2024
- Spyderco did a major run of knives using CPM-Rex 45 in 2020. The chemistry of the steel and most importantly, how they heat treated it makes for a nearly ideal EDC blade steel if stainless properties are not required.
In this video, I go through the chemistry and how it results in the final properties of the steel. I then translate it to real world toughness and edge retention results.
Sources:
1) Thomas, Larrin “Knife Engineering: Steel, Heat Treating, and Geometry” 2020
2) Spyderco mobile app.
New spyderco m4 is now testing around 64/66
Badass! Love hear they keep pushing the limit. Wonder how it’s performing, I’d imagine it’s very up my alley!
I like REX 45 as well as an EDC. Stainless isn't a big issue for me. I appreciate this video as a scientist myself and evidence based facts. Thank
Rex45 is one my favorites for sure. Glad you enjoyed!
Damn now I need a Rex45 pm2. Great video, love your explanations and how you compare steels to their contemporaries in a clear and precise manner👍🏼
Appreciate the feedback!
Best explanation and comparison of steels I've heard by far, well done sir!
Wow, thank you! Appreciate it!
You bet! A lot of people talk about these things but do a poor job of explaining conceptually (if at all) so that less knowledgeable people can actually understand how the variables work together. You do a great job of that, would expect no less from an engineer 😉
Awesome review! Thank you for this.
You're welcome! I'm glad you enjoyed it!
Very knowledgeable review. Rare to find thanks!
Appreciate it! Hope it was I formations!
Great video. Thank you for this. I really enjoyed it!
Glad to hear it!
Subbed. Great content. Good to see the steels demystified and given a good explanation on the similarities between ever new steels. I'm interested in picking up a Rex. The non stainless patina very well.
Thank you, I’m glad the info comes though somewhat clearly!
You know, I never really thought about hap40/rex45 in this way. I'm so used to seeing it on kitchen knives, I never truly considered it for my edc. I went with k390 recently on my endura. To me k390 is like hap40s high vanadium cousin or something.
In some ways I guess! I love both these steels and the heat treat that Spyderco has done is incredible for production knives. K390 drive is on off my most carrier knives right now
I have the PM2 and Endura in K390, love them. Just picked up the Shaman and Manix in REX45, looking forward to using them. I didn't know that Hap 40 is the same as REX45, will be getting some Hap 40.
Thanks for the video.
Nice picks on those Rex45 blades!
Just an FYI the Hap40 that Seki City Spydercos have is A LOT softer than how they ran Rex45. They feel like completely different steels. That Hap40 as they heat treated it is a sweet sharpening steel though!
I totally agree i have a military and a Sherman in rex 45 i use the military for fishing its long pointy blade is extremely good for filleting fish and the rex 45 keeps its edge when most steel gets hammered by the hard fish scales .in the past i used basic steel fishing knives and had to sharpen them veary often .not with rex 45 can't remember last time it was on the stones .it keeps on going and going .only down side is cleaning it and drying it . You can pritty much whach it rust if you dont look after it .MY FAVOURITE STEEL BY FAR .AND AFTER YOUR GREAT VIDEO I NOW KNOW WHY ITS SO GOOD .it all makes perfect sense
I absolutely love the stuff and K390 is a close competitor! Glad it made some sense too!
But rex45 isn't stainless , isn't it a problem for fish ?
@@dimmacommunication as long as you dry it off give it a quick clean at the end of the day its fine and does not rust that quick .if useing around salt watet sea fish etc i usually clean and dry it straight after use . My rex 45 still looks mint condition after a few years of use but i would not mind a bit of patina anyway
@@edwardthompson3213 Very nice, thank's for the answer.
I'm really considering an HAP40 ( rex45) kitchen knife
Great video, I hope to see more content from you in the future! Also I agree rex 45 is one of the best if not the best working knife steels
Thank you! I'm working out some details to do one on VG-MAX which is a kitchen cutlery steel. Let me know if there is any specific steel you'd be interested in.
@@EngineersPerspective701 would love to see your thoughts on Nitro V
Just uploaded the Nitro-V video. Hope you enjoy!
That's what she said. Im just getting into super steels, this is really interesting. So far i have s45vn and cruwear. Got k390 and s30v on the way. Been using the cruwear the most, ive been really impressed with the edge holding compared to 1095.
Cruwear is a blast and I do really like S45VN. You’ll have a really great spread of steels there for pretty much any need!
I dont know man, Shawn H. did a comparison of these two steels from Spyderco and the M4 couldnt keep up with the Rex-45 during hard use cutting.
Magic erasers clean g10 up so nicely. Only way to keep the orange clean. It’s a must
That’s a great tip! I have a 10V PM2 that needs some love
Does it remove snail trails or just color transfer from jeans?
Thank you for pulling it all together in a coherent, understandable, meaningful way for us. Your argument is very compelling. Would be nice to have a little more stainlessness though, which is partly accomplished with spyderco's hap40 versions due to the cladding.
I was hoping you would talk to the hap40 a bit more, or maybe I missed it, there were some distractions going on for me. Did you just get rid of the endura because they didn't get as high hrc as the rex models or were there some other factors?
That’s great that the info came through clearly! I really appreciate the kind words!
My bad, don’t use a script so I forgot to about it specifically! The endura just didn’t get carried so I sold it but I definitely regret it! With the softer Hap40 2 things stood out 1) It sharpened sooo easy and came up great. 2) It held a fine edge better than normal S30V, 20CV but it broke down more like a lower vanadium steel under use of that makes sense. Watch my S30V vs. k390 video for discussion on how they break down if needed.
@@EngineersPerspective701 I watched that video as well. Really enjoying the content. Thought I understood pretty well already but i believe your videos are giving me some additional understanding/ideas. Look forward to watching more.
@@turing2376 I've got some steel comparison videos and sharpening concept videos I want to do already so I hope you enjoy those!
It took me a loooong time and lots of actual using my knives to translate info from Triple B and Knifesteelnerds into practical knowledge. There is always more to learn for sure!
@@EngineersPerspective701 I had benefited from those sources as well but you have definitely added to the pot for me. Look forward to those upcoming videos.
@@turing2376 Let me know if you have any requests for specific topics!
I grabbed the GP Knives Rex 45 exclusive for the Native 5... looking forward to testing the edge stability. (I was a bit surprised to chip my M4 lil' Native prying a couple of staples off of wood... small chips, but it doesn't inspire confidence). This is by far the best video on Rex 45 I have found, but I feel like I'm still not quite wrapping my head around it. I understand that the low carbide volume is what allows it to be chip-proof at high hardness. But there's other steels that have low carbide volume... so I'm guessing they can't be heat treated as hard? Is that where the cobalt is important?
Really well sunk staples are the king of wrecking an edge I tell ya! Just to be clear no steel in a knife will be chip proof, but more resistant than others.
There are two factors that make Rex45 perform really well here and you touched on them both. 1) Toughness due to the low carbide volume 2) Strength due to the high hardness.
The edge really wants to hold its shape because it has elevated levels of both that are in a good proportion to each other.
The cobalt helps a lot in the heat treatment process to reach that high hardness.
@@EngineersPerspective701 Thanks, sounds like I mostly understand! Out of curiosity, what would you recommend for a long working edge (as opposed to fine edge), while remaining roll and chip resistant? Would it still be Rex 45, or would a stainless steel be better for a long working edge?
Got to say I agree with evey thing you said. Got my pm2 rex45 5 months ago. Also picked up a k390 endura. I bought the pm2 used off ebay, don't know the bevel angle but it was mirror polished and looks about like your 12 degree one. Geometry is king. That is the problem with edge retention tests on you tube. If you test k390 vs rex 45 at the same included angle you are doing the rex 45 a disservice. It can hold a more acute angle than k390. I am only concerned with fine edge, I have to many ways to sharpen a knife to let any of them get dull. My favorite to least favorite of the steels I own . Rex45,k390,cruwear,m4,14c28n,13c26,d2. Lost my s90v millie fishing it would have tied for 3rd.
100% I’m in the same boat. I will say I have learned over the past maybe 2yrs to appreciate a working edge more and get utility out of it but the fine edge is where I like to stay.
Got a rex45 pm2 coming. Had some reports that it is a little soft in the pm2, hpe not. Wonder if the hap40 is soft because of the cladding process. The manix2 in 4v are consistently testing above spec on hrc, between 65 to 66. I don't see much as far as testing of 4v on you tube. Maybe you have something on here, just found your channel, started at the beginning.
Clad Hap40 in Japanese kitchen knives is regularly above 65HRc so it’s not that. I think it’s just where Spyderco felt comfortable with it for whatever number of reasons at that time.
I have a para 3 in 4V. It sharpens Ana zing and holds a nice edge but I can tell the carbide volume is a little low so that limits it a bit for my likability. Still one of my favorites but second tier
have you tested or noticed a difference in performance with rex 45 with a high grit "polished" edge vs a lower grit?
I haven’t tested super polished edges much on Rex45. I’ve put a Venev 800F with 1um diamond strop edge on it a lot and it does really nice with that. It holds onto the bite for a good while but eventually blunts more than breaking down into a working edge due to relatively low carbide volume.
I used a 3K Chosera edge for a while and didn’t notice a huge difference which is a positive thing.
When I had Hap40 I did a lot of spyderco UF then a chrome oxide strop and could get hair whittling so easy from that. I think those were closer to 62HRc so they sharpened a lot quicker. Honestly the Rex45 doesn’t sharpen as nice. Still very good though.
So in a nutshell, great edge stability with some carbides sprinkled in as a bonus?
Nailed it!
Would you prefer k390 or rex45? I enjoy k390 a bunch
“It depends” is the true answer but if I could only own one steel for the rest of my life and I had to choose between the two it would be K390, assuming good heat treats. The carbide volume in Rex45 isn’t quite enough
I wonder how it pwrforms against same rockwell zdp, I have shaman rex45
I’d guess for edge wear the ZDP should smoke the Rex45. Better edge stability, very likely Rex45 but I can’t confirm
Did you get that 10v Para3 from Rivers Edge Cutlery? Its also a dealer exclusive if i remember right.
I sure did a few years ago maybe. It’s been a great knife for sure!
@EngineersPerspective701 you a local shopper or just online shopping?
@@EngineersPerspective701 concerning REC
@@AndrewsArachnids online. No amazing knife shops anywhere near me. Scheels and Cabelas are pretty much the local options.
@@EngineersPerspective701 awe that's unfortunate, I've grown up with REC in my back yard
Fine edge is all that matters. If it don't shave I don't carry 20cv creates a good edge and.is easy to touch up.
To each their own! I tend to lean into the fine edge camp too! I will say if you want some sweet fine edge magancut, 4V and good hard Cruwear are hard to beat
@@EngineersPerspective701 just got my 1st cruwear a manix2 KC B/B haven't used it much but it has a nice bite to it. Thanks for the lesson
What about spyderco,s ZDP-189? What do they heat treat it to?
ZDP-189 is very different from Rex 45 other than that it is also typically run very hard. I think some of the older Spyderco ZDP was in the mid 60s HRc but they possibly lowered it with the more recent models being below 64. Can’t say for sure though because only a handful were tested that I’m recalling the numbers from memory.
Outpost76 and michael cristy would be good channels to check out
@@EngineersPerspective701 I know that they are chemically very different. I was curious as to what spyderco getting there hear treat to. I have a old ZDP-189 delica and I remember reading that the spyderco heat treat sat at 64- 67. On a side note l have heard that some people have gotten ZDP-189 up to 70! Using a water quench. I believe that information may be from Hitachi or on Spyderco,s web site, I subscribed btw excellent vid my friend I'm definitely gonna have to getting my hands on some REX-45!
I'm on the hunt for a Sukenari in Hap40 that's under 210mm. They advertise 68HRc on theirs! I've been tempted by their ZDP-189 stuff while I'm waiting for the Hap40 to come back in stock but it's not what I'm looking for right now. They run the ZDP softer at 66HRc no doubt due to the lower toughness with all that chrom carbide in there.
U still think the rex45 fine edge retention will outperform the k390?? Bc I noticed you were forced to take off the k390 for additional testing. My vision is very blurry so I apologize for any error s can barely see.
Sorry to here that! Honestly I can’t say right now because I’ve been carrying K390 and Maxamet mostly so I’m a little out of touch with Rex45 at the moment.
If I was to guess I’d say yes that Rex45 will hold a fine edge longer than K390 but the way K390 breaks down during use can make it feel like a better cutter in the early stages of wear than Rex despite that
@@EngineersPerspective701 thank you. Yeah believe it or not my blurry vision is due to long covid so it can't be corrected with glasses, I've been symptomatic since the beginning of May. Unfortunately my immune system just can't seem to rid itself of the infection, atleast not yet.
So I'm guessing you ended up liking maxamet alote after all. Because I remember a time when you weren't really sure what to think of it and also how to sharpen it to your liking. Thanks again for the content and happy holiday's.
@@jimmycricket7946 Yes, I spent a lot of time really getting to know Maxamet and it may be my favorite steel of all time. It doesn't act quite like "normal" steel in sharpening or how the edge wears and I love it for that!
@@EngineersPerspective701 I know what your referring to I've heard quite a bit about maxamet and I would imagine it certainly does behave quite uniquely and 13% tungsten is alote, I think that's 3% more then Rex45 if I remember correctly. Maxamet is next on my list to try but it will be awhile because I just picked up X3 different seki k390 models and in trouble by the wife bc of it. Also, I remember you mentioned that you weren't able to get any 15V but if you ever do it would be nice to hear your thoughts on 4V, 10V and 15V in comparison. I'm still trying to figure out the historical timeline as far as the progression from vasco wear to 3V and cruwear and how the rest of the V family came into formation. It's been somewhat confusing and the existence of vanadis steel just further complicates thing's.i do know Without larrins publications I'd really be lost!!
@@jimmycricket7946 I highly recommend checking out Maxamet!
4V and 10V are completely different in use because of that huge jump in VC formed. I did get 15V and it’s completely overtakes the 10V REC PM2. It is 65Hrc plus the extra VC so it’s hard to say if it’s mostly hardness, carbide volume or quality of heat treat. I’ll at the sum of those things makes this 15V unchallenged by anything yet I’ve owned.
Isn't rex45 less tough at the same hardness than m4? Reason being tungsten. I could be wrong on this. I know Spyderco runs it harder than there m4.
By Dr. Thomas’s tests that appears to be the case and it’s probably better associated with the huge cobalt addition. I don’t think the actual cause of that is well understood, but fairly well recognized empirically. The question is wether or not that reduced toughness matters?
In my use it does not and Rex45 enjoys a huge increase in edge stability due to that big HRc bump. The biggest downside of Rex45 vs M4 is the lower carbide volume. It’s super apparent once the fine edge is gone but that does take a looong time to happen with Rex!
@@EngineersPerspective701 Rex45 is definitely good stuff! Thank you for your response. Nice to see more steel nerd videos on TH-cam! Always very interesting to me.
The issue here is just as much like the heat treats that production companies make available to us as end consumers as it is about the steel itself. Same for grinds, though you can more easily modify a grind than you could the heat treat on your knife.
That's important to remember. People talk a lot in theoretical, but I like to stick to being grounded in realities, like the reality of what you can actually get your hands on. Here in reality.
100% agree. I think how Spyderco did Rex45 is a perfect example of that plus the geometry they tend to use vs. others.
@@EngineersPerspective701 Spiderco is legit. They're just too damn ugly for even someone as unhip as myself to actually daily carry. Can't do it.
@@jeffhicks8428 😂 definitely hear that a lot. I think a person learns to love the looks!
So in theory Rex 45 should be easier if not the same to sharpen as M4? The only problem I have with M4 is the burr just going back and forth.
I have the same issue with the burr on M4. Seems like the very tough high-alloy non-stainless steels can get that way. However I have no such issue with the Cruwear I've experienced.
For Rex45 vs. M4 it's going to come down to hardness. Hap40 from Spyderco was softer around 61-62HRc. It was extremely easy to move and fast to take a keen edge but it was pretty lack luster in terms of edge holding for me. Compared to M4 at 63-64HRc and higher carbide volume, it was no comparison. But Rex45 at 67HRc is a totally different animal. It feels a lot closer to 10V class steels on the stones, high quality abrasives and a solid coarse stone are really recommended. I find it to have a much more stabile edge than typical M4 and takes a sweet, crisp edge so overall I prefer hard Rex45.
@@EngineersPerspective701 I just picked up some of spyderco's cruwear can't wait to sharpen I, thanks for the explanation!
This is why we love spyderco
Dang straight!
@@EngineersPerspective701 I just wish they would make the shaman in k390 that will never come out of my pocket lol it’s amazing and perfect steel for that knife
Trying to decide between Rex 45 and Elmax.
What you looking to do with it? Not knowing I’d suggest Rex45
@@EngineersPerspective701 Just regular, light EDC tasks, like light food Prep on lunch break or hiking. I am seeing three Sprint Run versions of the Shaman at similar prices, but can only afford one. ( M4, Elmax, Rex 45 and Cruwear). Maybe wondering which would be more desirable on the market down the road. I have a SpydieChef and Kapara and really love those 2, so really like Stainless, but something that can hold an edge at least as long as LC200N ( Which has surprisingly good edge retention, in my use, anyway.) Sorry to go so long. 😂 Wish they made one in LC200 N.
@@marckydasaint8730 Elmax seems to be very desirable for sprint runs and fits your use case probably best!
If you're really into sharpening you would probably love Cruwear or a second pick would be M4.
If you're looking to dip your toe into high hardness non-stainless I would pick Rex45 over the other options though! Rex sharpens really nice but you can tell it's hard as hell so I like to start on a coarser stone with it.
So rex 45 or s90v for a spyderco para 3 ! Whats the cream of the crop !?
Cream of the crop is Maxamet or K390 for me! But for you it may be different! I’d personally choose Rex but I haven’t actually tried s90v. Need to pick up a good hard s90v spyderco when they do another.
1) If you need stainless then S90V
2) If you don’t have diamond abrasives then Rex.
3) If you prefer keeping a hair shaving edge longer then Rex.
4) If you prefer minimizing sharpening and prefer an edge that never really goes completely dull S90V.
5) If you’re cutting lots of cardboard or rope then S90V.
Does that help at all?
@@EngineersPerspective701 thank you reason i asked is because i was about to buy a 400 bucks para 3 in cooper rex 45 just because i have a flashlight cooper and my zippo the limited cooper blend 27 when they came out 03 i think . Either way ive had s90v on a benchmade and i used to beat it up . I had 0 understanding of what rex 45 was . Im a chris reeve sebenza guy and i also have their special force and green beret fixed steel wich is s35vn . People ask what they want for rare discontinued stuff so i wanted to make sure at least im not getting a good shiny haddle but low end steel . Thank you for taking your time to explain i think im going to go with the rex lol🙌
Correction paramilitary 2 not 3 that was in cooper ****
I really don't see the value. They make up the price for steel that cuts a few more inches. Why does 14c28n hold up just as good as most of these. I really like xhp myself but I'm not seeing enough to make me spend $170+ when I can get $30- 70 knife that preforms almost as good. Every test I've seen we are only talking about 50 to 70 feet difference really 1095 is tougher then most of them. I just can't see it what do you think.
First, I wouldn't compare my test results with anyone else's so keep that in mind.
It can be tricky to translate the tests into real life use. In part because everyone's use is totally different! What you cut, how often, how you sharpen is going to make a big difference for how worthwhile high end steels will be.
A few ways are below:
1) Look at the ratios. 50ft vs.100ft is 50ft more but it's 2x increase. So if you're sharpening every 2 weeks, it would be more like every 4 with the better steel.
2) How the steel cuts over time will be very different. 14C28N will be sharp and then kind of just go dull. While something like S90V which has a lot of Vanadium in it will almost never get to that same level of dullness due to high number of vanadium carbides it has.
This is just the tipy tip of the iceberg.
@@EngineersPerspective701 I guess your right in my experience as a truck mechanic and iron worker the expensive knives have never held up in fact a liner lock failed and cut me bad. But I also had a s90v when it was a sprint run on a manix it was a chippy mess snap-on took it back for a loss.
Really my best experience other then 14c28n is xhp in coldsteel. I just don't see these expensive steels being worthwhile unless you cut miles of cardboard just my opinion I really enjoy how you lay things out keep up the good work.
I’ve been telling people for years
It's awesome stuff
When I start hearing about all this alphabet soup from the periodic table, I start to wonder ... did they leave any room for that _"old school"_ element -- *Fe?*
Just barely. Really Fe isn't worth anything without C
Your edge retention tests are nowhere near anybody else’s edge retention Test. You may wanna go back and sharpen those others some more. Each one is capable of Waymore than you stated. Also you keep mentioning toughness. With every point you Gain on HRC you are losing that toughness You desire.Also toughness it and add stability are two completely different attributes
Agreed 100% that my results are lower than others on YT. That said, I completely stand behind my results and just don't compare them to each other. It's all about how each test compares to the other within my own set of data. How they rank matches exactly to others out there. The idea that one can extrapolate the data from a test to cut exactly XX feet of cardboard needs to be reevaluated.
I believe I say "too tough to chip, to hard to roll". I think this tangibly translates how its combination of chemistry and heat treat translates to edge stability (high modulus of resilience=no rolling or micro chipping) and blade toughness (high fatigue limit=no large chipping). In this case, the toughness was wisely used (traded off) to hit a high HRc that resulted in an adequately tough steel and very stable edge.
The entire point of tough steels in my usage is to go harder. A soft & tough steel is a gross waste of potential because it's doubling down on attributes. Usually these 2 things are added to thick geometry in which case the designer triples down on toughness. The results of this common practice are lackluster and not interesting. Not to mention a knife that will plasticly deform when pushed past its limits.