Fri Mar 21, 2014 2:00 pm
I'm thinking about purchasing a knife in CPM M4. I will be using the knife at work and it will have edge retention tested daily. I'm looking for some opinions from people with experience with this steel.
Fri Mar 21, 2014 2:42 pm
M4 will hold an edge as well as any steel I've ever seen.
Fri Mar 21, 2014 3:20 pm
Its good stuff, can be ran very hard (64+) and takes a beautiful polish along with some breath taking sharpness. It's very tough even at high hardness and is easily maintained with a ceramic rod which produces a wicked edge. It nice to take it to fine levels of sharpness but a 1k edge maintained on a strop or ceramic rod typically will yield the best performance.
Because of its wear resistance you will need good waterstones or diamond stones.
Mon Mar 24, 2014 9:47 pm
I love CPM-M4, it may be my favorite knife steel. It is similar to Aogami Super in most respects, maybe just a little bit more stain and wear resistant. It will definitely show a difference compared to White Steel in egde holding, as in sharpening about half as often from my experience. It will also be more stain resistant, and a little more than 52100 or Super Blue, but not by much, I treat mine like they are plain carbon and have very little patina after a few months.
At similar hardness, it is also a bit more time consuming to sharpen than other steels, especially shirogami, but I use diamond right now (trying to pick that perfect first waterstone as we speak), so I have only noticed a small difference, but with a softer stone, this may become a larger, more problematic gap.
No worries with fine edges from me either, I finish around 2-3k and the edges between M4 and Japanese steels at that level feel identical. I'm no sharpening expert though, so take that with a generous pinch of salt.