The CPM REX 121 K2 Folder

I will soon (some time in May) have one of twenty of these custom folders with Titanium bolsters and frame by Fareed in my hands. He is an excellent knife maker with a reputation of making the finest knives from unusual steels. CPM 121 used ro make the 4 inch blade of the K2 also has a reputation…it is one of the hardest steels and in this case having a Rockwell hardness of 68-70. Has anyone worked with this steel before? If so, do you have any suggestions as to how to proceed with the sharpening of such a tough steel. Besides long periods of time on each level, does anyone know its characteristics? From what I have heard rumored, I am feeling a little daunted at the same time as I am excited about receiving the beast.
Any experiences will be greatly appreciated. Pictures when it arrives

Leo the scardey cat!

LOL!

Good morning Leo! Your timing for asking about the CPM REX 121 – just yesterday I finally got around to sharpening my mule from Farid. I was expecting it to be much more difficult than it was. I’ve documented here on my blog: Sharping the Farid Mule. In a nutshell, I chose 15 degrees per side and took it to one micron with the following progression:

100 grit diamond> 200 grit diamond> 400 grit diamond> 600 grit diamond> 800 grit diamond> 1000 grit diamond> 14mu diamond and leather strops> 10mu diamond and leather strops> 5mu diamond and leather strops> 3.5mu diamond and leather strops> 1mu diamond and leather strops

It took exactly 4 minutes total to raise a burr from both sides, the entire process took 22 minutes from start to finish including photography. My experience so far is that Diamonds+REX121=LOVE

Hi Leo, it looks like crazy steel mate 🙂 68-70 HRC, it must hold scary sharp edge several years 😀
Enjoy our new superb knife!
Lukas

Clay, how on earth can it take you that short of time to reprofile blades with the 100 grit stones?

It takes me up to 15 minutes per side to reprofile a blade using the 100 grit stones, and that’s on steels like S30V…. They just don’t cut fast enough for me to be done that fast, given that I am reducing the edge angle by 5 degrees or so.

I haven’t even tried the 15 degree settings for fear of it taking an hour per side with the 100 grit stones.

I was shocked how quickly it went, especially with my well worn stones. I don’t know if all the practice I have makes it quicker for me, maybe just a lot more strokes per minute or something. I’m glad I was actually timing it because I wouldn’t have believed it otherwise and would likely have overestimated the time.