More Edge Retention Testing - Rex 45, Maxamet, SPY27, XHP, CPM-T15, 420, Rex 76

[JRinFL]

Thank you Larrin for your continued work and for freely sharing the data.

[S-3 ranch]

Guess I better send my new Rex45 Native Chief back :p

You have to quit using Rex45 after Memorial Day, because it will rust stain your white pants :D
Rex is a winter knife :)

[Lucabrasi]

Seems like a pretty good win for Spy27 and xhp. Both seem to have the positive attributes of S30v/s35vn but sharpen your better. That has certainly been my experience with XHP.

[The Mastiff]

One of my favorite of Larrin's articles. I notice he had to be modest about the Larrinwear performance and where it fits in. It looks to be the stainless knife steel to have for my use. :)

Joe

[JMM]

Yeah, I'm a bit shocked by the Rex45 numbers, I've been using the first and second sprint models for a long while now and my experience is vastly different than these numbers. I EDC'd the original Para3 7 days a week for over a year and it was phenomenal . . . Interesting data indeed.

[Matus]

I'm sure rope or cardboard testing could be used to get consistent results. However, the majority of rope or cardboard cutting tests are done across a vast range or different knives which makes sorting through the results very difficult. It's just the nature of the beast when you have to rely on available knives rather than making them all the same. When you are testing different production knives you are testing knives, not steels.

I agree 100%

[sal]

Hi Larrin,

Great stuff. Thanx much for sharing. It's really valuable for us on this forum to have an educated Academic perspective. I don't know to how many forums you present your information, but this forum as a group is appreciative. We also appreciate your "style" of humility and willingness to adapt to new information is very impressive.

Now to "Talkin' Story",

Since the beginning of our company, Gail and I have always pursued perfornance as our "thing". We've been testing for decades using CATRA as well as other Lab testing. I also highly value what I call "RWT" or Real World Testing. I have been supplying various restaurants, sub shops all over the world with our Blue handled serrated 6" Utility kitchen knife, (K04SBL) which I consider, in my opinion, the most effective general kitchen utility knife available. I have been going back to check on these knives regularly. I bring them to "home" to "scope" ( I use 10X, 22X and 50X to study edges ). Then I sharpen them or replace them. They usually last several years of daily commercial use. The results learned are very valuable.

I have had the good fortune to have Mr. Ed Schempp as a friend and business associate. We have been going to the Eugene knife show since the 80's. We always watched the "Rope cutting contest, which Ed usually won. Cutting free hanging rope. 1" then 2 1" then 3 1" etc. I have seen Ed cut 10 1" manila ropes with one strike with one of his knives. One year, I asked him If I can inspect his edge with a loupe before and after the contest. He agreed and I followed through. There was no visible damage to the edge after all of the cuts. then Ed resharpened the knife for me and let me take it to Golden for a CATRA test. The CATRA results were not very impressive, even though the knife was ???

While I was in Japan visiting the Kitchen knife factory that makes many of our kitchen knives, I asked the P resident why the MBS-26 that they use punches way above it's numbers. MBS-26 is a proprietary steel made by Daido for this company. He said that he, "Meticulously follows the heat treating instructions from the foundry". They heat treat in Lead pots. Something I hope to get into in the future with Mike Blue and Ed Schempp.

I have learned that Blades/edges will often defy the numbers one way or another, which is why we are still using RWT, and why we make the Mule Team. You afficianados are also very valuable in our search for the best performance in all areas of the "Edge/Ghost".

Just some thoughts to share.

sal

[GarageBoy]

Now I'm curious how well the super blue of the Spyderco/Murray Carter knives stack up against seki super blue

With xhp so close to spy27 - does spy 27 still pull ahead when sharpening with it's finer grain structure?

Is 420 (no suffix) the same was 420j2 ?

[sal]

Hi Garageboy,

The Super Blue ( Hitachi) in the Miurrray Carter's knives is the same as Seki Super Blue.

sal

[Karl_H]

I think it’s important to understand that the CATRA test involves slicing silica impregnated paper. If you are’s slicing soft material filled with hard abrasive particles, the CATRA test will probably have little importance to you.

The REX 45 results matched my expectations. It is unique in that reaches very high hardness, without large carbides or a high volume of carbides. This makes it relatively easy to sharpen to a fine razor edge, which is resistant to rolling.

The only issue I have had with REX 45 is some micro chipping on the factory edge, while cutting bicycle inner tubes. Otherwise, I have’s had any issues with it.

[abbazaba]

Thanks as always Larrin for the data, and thank you Sal for the story.

It's funny that we are not all carrying Maxamet right? :p

Seriously though, it's no mystery for an old M4 fan why people love REX45 regardless of the number it put up. Never really connected with Maxamet for reasons/skills I don't know/have. Very curious to try REX 121 given the praise and the numbers, but I'm guessing I'll like 15v better anyway

[S-3 ranch]

RWT cleaning wild hogs, watched a guy clean 5-6 dried muddy hogs with a 20CV blade and then not touch it up, and it ate through a bunch of rope and feed bags like warm butter, I don’t know what a catra test is , but would definitely want to know more about 20cv I assume that it’s some super steel cousin?

[abbazaba]

RWT cleaning wild hogs, watched a guy clean 5-6 dried muddy hogs with a 20CV blade and then not touch it up, and it ate through a bunch of rope and feed bags like warm butter, I don’t know what a catra test is , but would definitely want to know more about 20cv I assume that it’s some super steel cousin?

20cv is very similar to M390 and 204p (which is included in Larrin's testing/chart).

[JuPaul]

Guess I better send my new Rex45 Native Chief back :p

I wondered if you'd end up with a Chief!

[JuPaul]

Thank you, Larrin and BBB! Always interesting and appreciated.

Seeing as I just bought a Spydie in XHP, I'm especially pleased to read these results.

[nerdlock]

Awesome stuff, Larrin. I'm really happy to see XHP still holding its own after all this years - it's one of my favorite steels like CruWear: balanced characteristics all around, without being too chippy in real world use. It can also tolerate the tropical humidity well, despite it being ranked poorly in stainlessness in comparison to other stainless steels.

[Gtscotty]

Excellent test session, my takeaways from the bigger picture Larrin has built:

- Can't wait to try Z-Max.
- Maxamet is a relentless edge-monster
- If you like Rex 45 you should also really like M390/20CV/204p, same edge/toughness balance with corrosion resistance
- S45VN is modern Elmax
- SPY27 and S35VN are pretty much interchangeable and strike a nice balance of edge retention and toughness.


Larrin, have you ever tested H1? There are so many disparate takes going around on that steel, it'd be interesting to see what the CATRA machine says about it sometime.

[Worm]

I think the TCC result for Rex 45 is where it should be:
above M4 and below M390
That correlates with most real world user reports I have read and makes sense in regard to steel composition.

One have also to consider Larrin's TCC results are for testing wear resistance.
That is why many user experiences might have a higher opinion of Rex 45 than the chart suggests.
Because real world use often includes edge degradation by edge deformation, as Larrin himself mentions.

I was a bit surprised by the low toughness of Rex 45 (which is still higher than S110V & M390 at lower HRC).
But considering at with HRC it is, it makes sense,
and leads to a higher edge stability compared to S45VN (with has about the same toughness at a much lower hardness).

I admit, at fist glance I also wished it would have been higher on the chart.
I like using Rex 45 and have four Sprint Runs in that steel.

Would love to see a T15 & Vanadis 8 Mule Team to see how it stacks up against Rex 45 in real world use.

[TkoK83Spy]

Guess I better send my new Rex45 Native Chief back :p

I wondered if you'd end up with a Chief!

When White Mountain Knives ran a deal last week, I couldn't pass it up for $154 I think it was?? More Rex45 in a model I haven't tried yet, and will be my largest folder. That all sounded good to me!

[ChrisinHove]

Brilliant article, thank you! Also for all the informative comments.

The Rex45 chart placements did stand out, tbh. All the glowing reports of it in use can’t just be hype, though.