Discussion Forums

Warrick Edmonds

Talking steels, there's been some serious movement on that front in the last while. Some very tough steels that were previously held in commercial lock by large knife making companies are now available to the general custom makers such as myself. I've just started experimenting with some of these over the last few months and the results are impressive. Early days for me but here's the little bit I've done;

Just some terms. Hardness is the measure of how much force it takes to drive a point into the steel. Toughness is a mix of wear resistance and ability to absorb abuse, and is reflected in edge retention.

CPMREX121. This is supposedly the toughest steel out there, getting up to an unbelievable hardness of RC=mid 70's. To put that in perspective, most knives are RC= 59 to 61 and it's a log scale. It would be impossible to sharpen without the right tools. However I've seen cutting tests where it just blows the opposition away in number of cuts before blunting, by something like three times. I've made one knife out of this but haven't tested it yet. I did try to stonewash the blade but couldn't, it was too tough.

CPMS110V. I won't be using this again. I made a hunter for my son and it's such a hard steel to work,...it saps all the joy out of life. I hope the edge retention is worth it. We're going goat hunting tomorrow for a couple days so we'll see how it performs. I also made a leather cutting knife from it for my own bench, = sheath making. It outperforms all my other tools by a long way, so it's the one I reach for all the time.

Bohler M390. This is my choice so far. It's ok to work though demands much more effort than 'normal' steels. It's a full stainless that can get hard, in the mid 60's, without losing toughness. That is, without getting brittle. But toughness and edge holding are high compared to the hardness. I've made a hunter out of this which is now with it's new owner but before I posted it away I tested the edge by cutting rope and 3.5mm thick leather to the point of blisters on my hands. 640 cuts of rope and 200 cuts of leather before it wouldn't easily cut A4 paper, though it would still shave my arm. It's an impressively good steel and I'll be using it more in the future. I put a photo of the pile of rope cut and leather strips on my website, new things page.

So, anyway, there's a few names for 'next gen' steels, sometimes called '3rd gen martensitic' or '3rd gen particle formed' that you can look into when you're considering your knife purchase from your favourite suppliers. There are plenty of production made knives out there using these steels or you could ask your knife maker to look into them. Just beware that REX 121 is a carbon steel while the other two are stainless. They are top shelf so, yes, that means there is a price premium, the only sad part of this story.

cheers
Warrick Edmonds
Riflebirdknives.com