Knifemaker / Craftsman / Service Provider
- Jan 17, 2004
On the contrary those results are so far apart they are unlikely to be explained by the PM difference. Phil Wilson in his rope cutting has not found a difference between 154CM and CPM-154. Some makers that prefer D2 over CPM-D2 will even argue that the larger carbides make it cut more aggressively. On balance I think the safest conclusion is that there is no difference when cutting rope or in CATRA.Yeah, I really should have checked beforehand if it had any good comparisons before I said anything.
The best example I could find in it is CTS 40CP vs 440C, same sharpener and edge angle used but no mention of hardness.
I'm thinking that maybe hardness isn't enough to explain the huge difference in there.
I searched for a comparison of 154CM and CPM154 for the same knife model (in order to have the same approximate grind, edge and angle) but found nothing on your link. If you filter for 154CM and CPM154 you only find that Pete tested different models with different edge angles :
I think you cannot compare steels if the grind, edge and angle are not exactly the same.
That's why the tests performed by Larrin on standardized knives are so valuable.
It all depends on your failure mode. If you are losing your edge to deformation then you need more strength. Either higher hardness steel or a more obtuse edge. If you are losing your edge to wear you need more wear resistance. If your edge is chipping you need more toughness. Edges can of course see mixed modes where you want a combination of strength, toughness, wear resistance, and corrosion resistance.
We did 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...eels-xhp-spy27-maxamet-rex-45-420-t15-rex-76/
1) My K390 is too thin for a toughness specimen. It is somewhere between 10V and Vanadis 8 when at the same hardness.Excellent information! Two questions:
1) I see that K390 has a CATRA result, but no toughness result, would you expect it to have similar toughness to Rex 45/Rex 76/ Z-Max?
2) Where would you predict H1 to fall in to the CATRA graph?
Thank you for creating this excellent data repository!