CPM M4 HRC

ShannonSteelLabs

ShannonSteelLabs

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Sep 9, 2015
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I was curious on M4s best usable hardness.
Looking for a balance on edge holding and toughness.
Then a balance with a focus on edge holding. Never used M4 before and I wanna try it.


I had thought about 62HRC but not sure if I should go for 63 or 64.
 
First, depends on what your intended tasks are
Second it depends on the edge geometry you are planning to use
A really thin edge slicer should be ran hard in the 64-66 range
A camp knife or chopper should be around 60-61, with a moderately thin grind.
Make the edge a little thicker on that chopper and you can run it a little harder.

BladeSports Competition knives in M4 are typically 61 Rc with an edge thickness around .025"
Even at that there is the occasional chip and the rare chunk that will come out of the edge.
These are heavy yet streamlined choppers. You want the edge thin for efficient cutting.

It's a balancing act and sometimes you have to find that failure point to find the balance point.
 
I have a Gayle Bradley 2 with a very thin hollow grind. Its 63-64 Rc and it is near perfect for a hard use folder. It is about .007 behind the edge. It can and does chip when abused but it is minor. I would run it harder for a slicer.
 
I’ve been testing M2 at 62 rc, with very good results! I’m carrying an edc I made in m4 at 64 rc right now. I would imagine if M2 is as tough as I’m finding it, m4 will hold up just fine at 62 to 64.
 
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Big Chris said:
First, depends on what your intended tasks are
Second it depends on the edge geometry you are planning to use
A really thin edge slicer should be ran hard in the 64-66 range
A camp knife or chopper should be around 60-61, with a moderately thin grind.
Make the edge a little thicker on that chopper and you can run it a little harder.

BladeSports Competition knives in M4 are typically 61 Rc with an edge thickness around .025"
Even at that there is the occasional chip and the rare chunk that will come out of the edge.
These are heavy yet streamlined choppers. You want the edge thin for efficient cutting.

It's a balancing act and sometimes you have to find that failure point to find the balance point.
Click to expand...
Thanks! Yea I'm looking to find that balance point really make the steel shine.
I typically grind very thin but can play with the edge geometry.

I think the first one will because thin slicer or EDC 3-4inch blade. Next would be a camp knife 5-8inch blade.
 
Big Chris said:
First, depends on what your intended tasks are
Second it depends on the edge geometry you are planning to use
A really thin edge slicer should be ran hard in the 64-66 range
A camp knife or chopper should be around 60-61, with a moderately thin grind.
Make the edge a little thicker on that chopper and you can run it a little harder.

BladeSports Competition knives in M4 are typically 61 Rc with an edge thickness around .025"
Even at that there is the occasional chip and the rare chunk that will come out of the edge.
These are heavy yet streamlined choppers. You want the edge thin for efficient cutting.

It's a balancing act and sometimes you have to find that failure point to find the balance point.
Click to expand...

Are you using Crucible's heat treatment protocol? IE preheat 1500 deg, equalize then ramp to 2100 deg for 20min. Plate quench then temper 1000 deg for 2hr X 2
Thanks
 
Robert Erickson said:
Are you using Crucible's heat treatment protocol? IE preheat 1500 deg, equalize then ramp to 2100 deg for 20min. Plate quench then temper 1000 deg for 2hr X 2
Thanks
Click to expand...

Not quite.
However, application also determines the heat treat protocol used.
 
I’m using the low temper heat treat on mine. Very good edge stability and Edge retention. I have more testing to do when I get time. I’m thinking m4 and 4v for hunting blades personally. They’re both bad ass steels. Very tough, and they hold a very good toothy Edge.
 
Big Chris said:
Not quite.
However, application also determines the heat treat protocol used.
Click to expand...
Chris I don't want to derail his thread but I am wanting to build some big choppers and a competition cutter. I bought 80CrV2, A2 and 3V to get started, all 1/4". I will try some of the more expensive steels when I have a proven knife. Do you have any advice? I know you have done a lot of these.I still need to upgrade my membership or I would have sent a PM. Sorry to OP for the Side bar.
 
skillgannon said:
Chris I don't want to derail his thread but I am wanting to build some big choppers and a competition cutter. I bought 80CrV2, A2 and 3V to get started, all 1/4". I will try some of the more expensive steels when I have a proven knife. Do you have any advice? I know you have done a lot of these.I still need to upgrade my membership or I would have sent a PM. Sorry to OP for the Side bar.
Click to expand...
No worries man!!
I would say try 80CRV2 to start. Get it dialed then move to 3V. But it's more difficult to grind as a heads up. Worth it though, my favorite steel!
 
P
skillgannon said:
Chris I don't want to derail his thread but I am wanting to build some big choppers and a competition cutter. I bought 80CrV2, A2 and 3V to get started, all 1/4". I will try some of the more expensive steels when I have a proven knife. Do you have any advice? I know you have done a lot of these.I still need to upgrade my membership or I would have sent a PM. Sorry to OP for the Side bar.
Click to expand...
Personally I don’t like 80crv, I had way better results with 8670. Something to look into.
 
ShannonSteelLabs said:
No worries man!!
I would say try 80CRV2 to start. Get it dialed then move to 3V. But it's more difficult to grind as a heads up. Worth it though, my favorite steel!
Click to expand...
Thanks.
I have some big blades in progress with the 80CrV2 but I bought a big chunk of A2 that I am going to make a competition chopper with.
M4 is my favorite steel. I just got my oven so hopefully I will have a hunter and a chef knife pretty soon. I have been sitting on a piece of 3"x3'x.15ish stock for a year now.
 
I would give it a try and report back. Can I get by with 321 foil and sub zero quench pr do I need to order more stuff. I would do a 7" chef knife. I would like to try it at 65-66Rc for kitchen use.

If anyone knows a heat treat recipe that I can do with my equipment I can run up a test blade.
 
skillgannon said:
Chris I don't want to derail his thread but I am wanting to build some big choppers and a competition cutter. I bought 80CrV2, A2 and 3V to get started, all 1/4". I will try some of the more expensive steels when I have a proven knife. Do you have any advice? I know you have done a lot of these.I still need to upgrade my membership or I would have sent a PM. Sorry to OP for the Side bar.
Click to expand...

Since ShannonSteelLabs said fine I'll derail slightly.
Making choppers and camp knives is fun and doesn't need to be too scientific.
Building a Competition Chopper for BladeSports Competition is whole different animal.
Everyone has their steel of choice and corresponding heat treat they prefer, specific bevel grind, specific handle shape, weight, balance point, etc...
It is a very specialized knife in that it is used very hard for a minute or so, has to stay indexed in your hand, has to maintain a keen clean edge.
It was on the fifth knife I made that I settled on a design, handle, and blade geometry.
I am still tweaking things though, weight balance point, and playing with different grinds.
A lot of things can not be put accurately into words, you really need to try and attend an event to handle knives and talk to the makers.
 
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