REX 45 vs S45VN use cases - also a question about your preferred thinness of a blade?

[Hashishiin]

Hi, I was wondering what the specific use case would be, where you may want S45VN over REX 45. I know that REX has been known to shave solid metal rods. So, what exactly does S45VN have up on REX 45? Like, Cruwear can't cut for as long, but it will take more impact. Maxamet is supposed to slice and slice all day. What is the thing you take 1. S45VN out for, and 2. REX 45 out for? How... tough (I think tough the word... 1095 is tougher, Maxamet is stronger, right?) , is S45VN? I'm gonna try 'em and find out, just want to hear what you guys think, so I have an idea what to expect and see if I'll surprise myself.

 

[StoneAndSteel]

There is a lot of qualities mentioned in there that may need some clarification. But the last question of S45VN vs REX45 boils down to one is a stainless and one is not. I can’t say that I have tested those two steels head to head in the same knife geometry, but I would take S45VN when corrosion resistance and edge retention were the concerns. I would take REX45 when I was looking for an edge that isn’t as prone to chipping or wearing quickly.

There are A LOT of factors beyond the steel like hardness, geometry, medium to be cut, and even things like body chemistry (I can’t carry high carbons in my pocket due to how salty my sweat is—no joke). Truly I think your best bet is to try both so you see what seems to work best for you. Often you’ll find that others recommendations on a particular knife or steel just doesn’t suit you.

 

[Hashishiin]

There is a lot of qualities mentioned in there that may need some clarification. But the last question of S45VN vs REX45 boils down to one is a stainless and one is not. I can’t say that I have tested those two steels head to head in the same knife geometry, but I would take S45VN when corrosion resistance and edge retention were the concerns. I would take REX45 when I was looking for an edge that isn’t as prone to chipping or wearing quickly.

There are A LOT of factors beyond the steel like hardness, geometry, medium to be cut, and even things like body chemistry (I can’t carry high carbons in my pocket due to how salty my sweat is—no joke). Truly I think your best bet is to try both so you see what seems to work best for you. Often you’ll find that others recommendations on a particular knife or steel just doesn’t suit you.

Thank you for your thoughtful answer.
Sure, I'll clarify anything. Qualities like what? I'm trying to learn strength vs toughness, I still have a rudimentary understanding but it was my understanding that hardness causes strength (not toughness) which is what allows steel to, say, cut through other steel, or heavy aluminum without damage. Toughness is the ability to withstand a lot of foot pounds of force. This is my understanding and I would love to be taught if this is the case.

I should have been specific that I was talking about all of these steels (S45, Rex, Cruwear, Maxamet) in terms mainly of the Paramilitary 2, as I have these. I just did not wanna alienate people with a "PM2 thread" so I tried to keep it more general. But heat treat, geometry, etc is the Spyderco PM2. Should have said that. I have bought two sets of custom scales - blue/purp engraved Ti, and carved wood with flowers. As I think the wood is more delicate, I was going to put the most delicate blade in wood scales, the Maxamet. I was going to put the Ti on a more "hard use" steel, either my Cruwear, REX 45, S45 or BD1N, but the thing is I like the Crucarta and the copper. So, that leaves S45 and BD1N, short of getting another Cruwear blade (which... is not a bad idea honestly, Cruwear rules). Also just wanna learn more about my steels.

I have heard of some peole who's sweat can be corrosive, haha! Body chemistry. So far, I have not had any steel properly develop a rust spot that stayed. Once left a Douk-Douk open by the sink and the water rusted it right quick, but I scrubbed it off, and another time I had some rust on my Opinel that I rubbed off. Live in CA, close to but not by the beach. I have carried Cruwear to positive effect, and have had no probs with REX 45 though I do need to carry it more. I hear it is better than M4, which my girlfriend uses in her work knife every day and is fine. Both DLC, so I think that helps.

 

[HP2114B]

Based on Spyderco's typical heat treatment, Rex 45 has better edge retention, much higher hardness and superior edge stability compared to S45VN. S45VN is stainless and a little bit tougher. Rex 45 edge characteristics are the best in Spyderco's current lineup, IMO.

Rex 45 can definitely patina, though it seems to be more resistant to developing orange pitting rust when compared to M4, K390 or 10V. I've only been able to produce a patina on Rex 45 by cutting hot acidic foods, which causes it to develop a faint blue patina.

 

[Hashishiin]

Based on Spyderco's typical heat treatment, Rex 45 has better edge retention, much higher hardness and superior edge stability compared to S45VN. S45VN is stainless and a little bit tougher. Rex 45 edge characteristics are the best in Spyderco's current lineup, IMO.

Rex 45 can definitely patina, though it seems to be more resistant to developing orange pitting rust when compared to M4, K390 or 10V. I've only been able to produce a patina on Rex 45 by cutting hot acidic foods, which causes it to develop a faint blue patina.

Thank you for this info! I knew Rex had some amazing attributes, just was not sure of it's specifics. I actually have dropped S45 and Cruwear on the same floor and noticed microchipping in the S45 but not the Cru, which makes perfect sense. 10V was another steel I was interested in, I may get a heavily patina'd version, but I hear amazing things of the steel.

I have a DLC Rex 45 blade, which seems to help the corrosion resistance a bit. It's the linerless milled copper exclusive. I'm thinking of perhaps switching that with my S45VN, and using those liners to put the Rex blade on these... thought I have to see if the DLC matches nicely. Want to use a high-performing steel for these babies.

 

[StoneAndSteel]

I think the PM2 is awesome BECAUSE of that exact reason: lots of steels in the exact same geometry (Spyderco’s heat treat is really consistent in a given steel so you can count on what you’re getting). Frankly, the only metric I know of for steel termed as “strength“ is tensile strength which doesn’t really apply to knives. Maybe someone else can weigh in on that. I think of toughness as resistance against deformity without fracture. Knife Steel Nerds and Carother Perfomance Knives is where I have gotten a great deal of my LIMITED understanding of steels and their qualities. Lots of guys here on BF have a wealth of knowledge, but sometimes it‘s hard to tell the difference from those who actually know what they’re talking about and those who are simply dedicated to that knife they just bought. Hence my reluctance to really dedicate to “get the X version!” I know what works well for me and it often doesn’t overlap with what others swear is the BEST knife/steel/handle material. Still, I have a storied hobby of trying different grinds, steels, coatings, handle materials, etc… But I burn through a bit of cash doing it. Less than my wife’s wasteful spending, but still…

Toughness is actually the quality that I look for first in steel I haven‘t tried before. I have chipped a lot of stainless steels with what I tend to cut and how. I also tend to have to sharpen knives in the field. With those two quirks I tend towards non-stainless’ fixed blades (since non-stainless folders spot in my pocket even with quality rust inhibitors). If I carry a pocket knife it is a stainless with higher than normal toughness that strops well in the field. One exception is a Delica in CRUWEAR that I absolutely love to carry in a thigh pocket. I just live with the spots. I have seen guys claim DLC will inhibit rust and conceptually it makes sense, but it made no difference for me on multiple blades when I tested it in North Carolina. Your mileage may vary, but that’s my anecdotal experience.