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

[Larrin]

A new set of edge retention tests on a range of high speed and stainless steels including Rex 45, Rex 76, CPM-T15, SPY27, XHP, and 420. We also did toughness tests on several of those steels that we had not yet been tested. And we redid our Rex 121 knife with a new heat treatment that was much easier to sharpen so it got a significantly higher score. https://knifesteelnerds.com/2021/05/10/ ... 15-rex-76/

[u.w.]

Oh yeah :)
Thank you Larrin

u.w.

[Nick258]

A little disappointed in Rex45. I though it had more edge retention. The extra hardness + Cobalt really dropped the toughness.

[Snacktime]

Really though REX 45 was going to be higher edge retention, even feels like REX 45 has higher edge retention in use. **** 420C killed it in toughness!

FYI Some of the picture links are broken in the toughness section.

[TkoK83Spy]

Yea that shocked me too about Rex45. In my use it's been amazing for edge retention on all 3 knives I've used it. Still my favorite steel regardless what the science says! :)

[RustyIron]

Thank you, kind sir.
And the commentary to help us navigate the charts is appreciated.

[Henry_P]

“ I was probably most impressed with Z-Max and Maxamet in terms of their combination of toughness, hardness, and edge retention they have, though of course still at the lower end of the toughness spectrum.”

Good to see maxamet is getting some love. A couple of bad blades in the past seem to have given it a bad reputation.

“ XHP has a competitive toughness-edge retention balance with other stainless steels, though its corrosion resistance is worse.”

I have always been a fan of XHP and it has been stainless enough for me in my use.

Thank you for this informative article.

[Dan In MI]

Lots of that is over my head, but still a good read. There is much learnin' for me to do!

[Larrin]

Really though REX 45 was going to be higher edge retention, even feels like REX 45 has higher edge retention in use. **** 420C killed it in toughness!

FYI Some of the picture links are broken in the toughness section.

The images are working on all of my devices. Maybe it was a fluke of the server.

[curlyhairedboy]

Man, I knew there was a reason XHP is one of my fave steels....

Thanks for the effort, Larrin + team!

[Wartstein]

1.) I am also surprised concerning REX 45 - in my use it seems to retain a useful sharpness like forever...

2.) Said in some other post that for me XHP feels like having about the edge retention of S30V but is a bit easier to sharpen.
Correlates much with Larrins objective findings: Edge retention not too far of from S30V (and higher than on 35 and 45 VN), and (quoting Larrin) " having only chromium carbides (as opposed to vanadium) makes it relatively easy to grind and polish with standard abrasives" - this probably explains what I found in my use of XHP.
And since I don´t care for corrosion resistance, this is actually a great steel for me

[Senfkarte]

Thanks a lot. I always wondered how REX 45 would fit in. Although I have to admit, my guess would have placed it higher in the charts.

[Wartstein]

Man, I knew there was a reason XHP is one of my fave steels....

Thanks for the effort, Larrin + team!

You beat me for a few seconds in praising XHP -
And: Yet another reason why people should get a Chaparral... :)

[hookandlateral]

Yeah put me in the group thinking Rex 45 would do better. Oh well, doesn't stop me from enjoying it.

[z1r]

Man, I knew there was a reason XHP is one of my fave steels....

Thanks for the effort, Larrin + team!

You beat me for a few seconds in praising XHP -
And: Yet another reason why people should get a Chaparral... :)

Yup. Need me another Chap!

[Matus]

I think it should be fair to say that different type of testing is going to bring slightly different edge retention results. Larrin of course uses the golden standard - the Catra testing. We have seen somewhat different relative results (I mean comparing how two different knives in different steels perform) when looking at rope or cardboard cutting (though these are not anywhere close as scientific).

But yes - I did not expect to see quite as low toughness for the Rex45. I guess one should not confuse toughness for edge stability (and a reminder to myself to go and read up on these topics on Larrin's blog)

[Larrin]

I think it should be fair to say that different type of testing is going to bring slightly different edge retention results. Larrin of course uses the golden standard - the Catra testing. We have seen somewhat different relative results (I mean comparing how two different knives in different steels perform) when looking at rope or cardboard cutting (though these are not anywhere close as scientific).

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.

[TkoK83Spy]

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

[Wartstein]

I think it should be fair to say that different type of testing is going to bring slightly different edge retention results. Larrin of course uses the golden standard - the Catra testing. We have seen somewhat different relative results (I mean comparing how two different knives in different steels perform) when looking at rope or cardboard cutting (though these are not anywhere close as scientific).

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.

This was especially noticeable with BD1N and LC200N (both great steels which I like a lot, don´t get me wrong!):
After the then available rope cutting results people (me included! ) thought BD1N would be between VG10 and S30V in edge retention, LC even just as good as S30V - when your controlled tests showed that both are even below VG10 as far as I recall. (EDIT: ... and LC200N actually below BD1N...)

[z1r]

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

To me? :D I've been looking for a low performing steel to practice my sharpening skills on! :p