Get on real computer, go to You Tube, and watch edge "Stability" routines this man does. Some supposedly low toughness steels really do hold up very well at the edge. Any site on a phone is about 1/4 as good as a site on a real computer. The code for the phone and the mobile site it directs you to are "light" so any phone can display the short form content. You buy the phone with the whiz bang processor, but the processor gets fed bread and water.Ogre wrote: ↑Sun Mar 05, 2023 8:36 pmI too am wondering what a good edge angle for this steel would be. I'm seeing another brand put a 14° edge on CPM-S90V and CPM-154. With M398 being high on edge retention but low on toughness, would a 15° or 17° be prone to chipping? Or, should I opt for a 25°ish? I'm thinking this will be, primarily, my bird and trout... (and cardboard) knife.
https://www.youtube.com/@FearNoSteel
The toughness test takes a bar of metal, supports it on both ends and then slams a weight into the middle to break it. A long standing metal test. However, it is more about a bulk property when you use the metal to make tooling. Edge stability is a product of the elastic strength of the steel where it deforms and pops back like a spring. And the ultimate strength of a steel where it is actually breaks. Many steels have properties that allow it to bend past springing back a long way before it breaks reaching ultimate strength. On the edge your failure may just be a roll in the edge, plastic deformation, or a loss of a piece of edge, ultimate failure.
The M398 Mule has been tested and the HRC is around 64. That from my research is what people have had custom knife makers provide in M398 as a sweet spot. At 62 it lacks some. That referenced You Tuber above has done a knife in M398 at 66HRC.