Farid CPM-REX 121 chopper

farid.

farid.

Knife Maker
Joined
Oct 26, 2010
Messages
1,395
For some time I have thought about making a very special chopper and wanted to use the best wear resistant Crucible CPM steel available. I started this project last year.
The steel of choice is CPM-REX 121, it is the first Crucible CPM steel which have managed to reach 72 rockwell hardness. The composition of this steel is nothing less than incredible. You do not need this steel for everyday cutting tasks, but I would like to try it as it is the best wear resistant steel that crucible makes. The grinding process is going to be hard as I am getting reading of between RC44 to RC57 in the annealed condition. Heat-treating this will require 2237F.
I will keep you all posted on my progress.
Thank you all for your time and interest.
Farid

CPM-REX-121 CHEMICAL COMPOSITION
Carbon 3.40 %
Chromium 4.00 %
Vanadium 9.50 %
Tungsten 10.00 %
Cobalt 9.00 %
Molybdenum 5.00 %


I will heat-treat tomorrow.

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holy crap that steel is ridonculous!
 
Lorien said:
holy crap that steel is ridonculous!
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Just wanted to share some info with the members on a project that started last year, I am aiming to finish the two in a few days time.
Thanks for looking.
 
Mercy!

I hope you're thinking about sending Mikey B. one of these . :)

I'll drive over and help him lift it. LOL!

B
 
That still composition is nothing short of incredible. Thats like freakin adamantium or something. Dang I want some. Nice work by the way :)
 
Thank you all for your comments,
Last year I went to a forging weekend at a friend’s place and tested my CPM-10v chopper on some 15mm copper pipe, it did very well, CPM-10v is a top quality steel but I think the CPM-REX-121 will be much better.

http://www.youtube.com/watch?v=lcCjUOp5F2U

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norcalblacktail said:
Very nice Farid. Looking forward to seeing it all finished. What rockwell are you shooting for?
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Hi, Heat-treating right now as we speak, hardening at 2150F, then temper 4 times at 1050F, that's good for 70RC.
talk to you later.
 
Very nice grinds. :thumbup:

Just in case anyone isn't familiar with the metric system, this beast is a tad over 1/2" thick! :eek:
 
Awesome looking knife and clean grind lines. Looking forward to your testing results. That Rex 121 has some serious composition. Wear resistance and red hardness should be exceptional because of the high amounts of cobalt and tungsten. I am sure finish grinding will take some serious elbow grease as well. Interested in seeing how tough it will be at that high hardness.
 
What does a chunk of steel like that cost if a guy wanted to buy a bar of it? I can't imagine how difficult it would be to finish that thing!
 
Hello Farid,

I've been keeping an eye on this project over on BB for a while now. I can't wait to see how this performs...but looking at that composition again, I'm sure it will!:thumbup:

I hope to get over to Knives 2011 this year. Will you be going? If so, it would be nice to have a chat....and hopefully see this knife in action.:cool:

Ian
 
irbailey said:
Hello Farid,

I've been keeping an eye on this project over on BB for a while now. I can't wait to see how this performs...but looking at that composition again, I'm sure it will!:thumbup:

I hope to get over to Knives 2011 this year. Will you be going? If so, it would be nice to have a chat....and hopefully see this knife in action.:cool:

Ian
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Hello Ian,, all kinds of problems with warping when I was hardening the blades, I had to put both of the blades one at a time under a 15 ton hydraulic press while still pretty hot to straighten them out since I couldn’t do it manually. Talk to you later mate,
Farid
 
I like to thank you all for your patients, I know some of you have been anxious to see these two CPM- REX -121 knives finished I have managed to complete one of them, oh well they only took around 6 hours and a WHOLE BUNCH of Ceramic belts to grind them to finished size after heat-treating. I have tested the blade and I am reading around 65-66rc on the thickest sections, I have no doubt the thinner sections around the edge is around 68-70rc since that area air cooled much faster than the ½” thick sections of the blade.

I like to thank all the friends at ZAPP in Germany and Crucible Steels in the U.S for their time and advice on this Unbelievable steel.

CPM-REX-121 was said to be the most difficult steel and most wear resistant to work with in the world.

It Was

Take care all,
Farid

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now THAT looks like fun!
 
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