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Fri Mar 21, 2014 8:00 am

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.

Re: CPM M4

Fri Mar 21, 2014 8:42 am

M4 will hold an edge as well as any steel I've ever seen.

Re: CPM M4

Fri Mar 21, 2014 9:20 am

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.

Re: CPM M4

Mon Mar 24, 2014 3:47 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.
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