Steel questions

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Storm W

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Feb 19, 2019
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I have been looking into Crucible and Carpenters catalog and saw some things that looked interesting. If I understand correctly Crucible is saying that what they are calling Spray Form is the latest generation of powder metal technology. Am I correct on that and if so what advantages does it bring? With that I said that they are making PSB38 that is basically a powder metal M2. I don't suppose Larrin Larrin has done any testing or has it in the pipeline yet? They are showing it to have higher toughness than M4. That sounds really interesting to me.
The other one was Carpenter has a powder M3.

I did a fair bit of looking and couldn't find anyone who was listing it without calling for a quote and I assume large sale. I could find a powder M3 in the EU but shipping and exchange will probably suck. Has anyone tried either of those or know where to get them?

I have been interested in M2 and M4 since I started making knives but do to health issues I haven't completed many knives until recently. My latest knives are M2 and M4 at 66Rc and it's fun shaving with my EDC vs my straight razor and still having a general purpose edge that hold up to carving hardwood at 6 degrees per side. Those steels have an edge that I haven't encountered on anything else. They are still a bit light duty and don't take impact at all. I can't wait to try Apex Ultra but I'm looking for something with a bit more toughness at that high hardness. How many of you guys are working with really any steels at really high hardness and especially the high speed steels. I'm trying to keep my edges very thin and really trying to push high levels of low angle sharpness and cutting ability mostly for small EDC type blades and chef's knives. If I understand things correctly, so long as I have enough toughness for the task the harder I go the lower I can drop the bevels and increase sharpness when adjusted to the task all things being equal. I think for a lot of task toughness is a little overrated although there is going to be a minimum threshold for anything. So far chipping has never been an issue. I don't know that this is a common line of reasoning but it's what interest me. I don't know if there are any less common steels that I am over looking. I guess Magnacut and 4V class stuff is something that I haven't tried yet. I would be interested to know how far people have pushed them before they had chipping issues.
 
I have a CPM Cruwear knife that is in the 64-65 Rc range and have been impressed at how well it holds up to my demands. I have used M4 for years but prefer the Cruwear as I do like the added corrosion resistance.

I would love to see a PM M2 steel available in thin stock.
 
I wonder how many people around the world are reading Larrin's book at any given moment?
 
Seedy Lot said:
I have a CPM Cruwear knife that is in the 64-65 Rc range and have been impressed at how well it holds up to my demands. I have used M4 for years but prefer the Cruwear as I do like the added corrosion resistance.

I would love to see a PM M2 steel available in thin stock.
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Agreed on the z wear/cru wear. I don’t understand why anyone would need more performance than what cru wear offers
 
HSC /// said:
Agreed on the z wear/cru wear. I don’t understand why anyone would need more performance than what cru wear offers
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Have you tried M4? It's just different. I have some nice top of the line Z-Wear knives and they really nice but don't compare. It's quick and easy to get to straight razor sharp, it gets a patina that I find attractive and I have never had any problems with rust. I wouldn't say it's easy to grind but once you learn how it's not bad at all. I'm not going to try to convince people if they don't like it but I do. Combined with the large radius hollow grind I'm coming up with a blade that I really like. My future knives will be thicker stock than I used to run. This way I keep the blade very thin until about halfway up. I think there might be a little food release with the convexity. The big hollow makes the blades lighter than they look but they do have a bit more heft. It makes for a very stiff blade as well and I think it feels like a higher quality knife just because of solid feel.
 
Storm W said:
Have you tried M4? It's just different. I have some nice top of the line Z-Wear knives and they really nice but don't compare. It's quick and easy to get to straight razor sharp, it gets a patina that I find attractive and I have never had any problems with rust. I wouldn't say it's easy to grind but once you learn how it's not bad at all. I'm not going to try to convince people if they don't like it but I do. Combined with the large radius hollow grind I'm coming up with a blade that I really like. My future knives will be thicker stock than I used to run. This way I keep the blade very thin until about halfway up. I think there might be a little food release with the convexity. The big hollow makes the blades lighter than they look but they do have a bit more heft. It makes for a very stiff blade as well and I think it feels like a higher quality knife just because of solid feel.
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I admit that I haven’t tried it.
 
Have any of you tried K390, and can compare to Z/Cru wear? I love k390 for the edge retention and haven't had any chipping issues yet, but is is a pain to finish after 120 ceramic (66 hrc).
 
When I started using M4 for me it was the best choice as I was able to easily reach a rockwell I wanted following the industrial high temper harding protocol. I EDCed an M4 knife for 3 years and the knife saw many farm and wilderness camp chores besides daily life use. Well now with the results I get with Cruwear using cryo and a low temper I will no longer be using M4.
 
Scaniaman said:
Have any of you tried K390, and can compare to Z/Cru wear? I love k390 for the edge retention and haven't had any chipping issues yet, but is is a pain to finish after 120 ceramic (66 hrc).
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Have you tried using the Norton Norax U936 ceramic belts for finishing steel like that?
 
Bunker Hill Blades said:
Have you tried using the Norton Norax U936 ceramic belts for finishing steel like that?
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I have, I tried one belt in Arizona before I left. I don't recall anything fantastic about it
Wear resistant steels don't really respond to higher grit belts on a machine grinder
Diamond film abrasive does work.
 
Knife Engineering

I've read the non reference portion twice, and still open it once a week or so for reference. It's hard to pack all that info in this tiny brain!
 
Early on, Crucible made CPM M-2. They found, however, that there was no benefit because of its already fine structure. M-2 has a lot less carbon than M-4 producing finer carbides and grain structure. There would also be no advantage to making M-2 with spray form technology. If you can find ESR-M-2, that would be your best bet.

Hoss
 
I'm with Keith. I probably pick up Larrin's book four or more times a week to check something for someone or refresh something for myself. It sits on the computer desk along with the ASM Heat Treater's Guide (which I almost never open since Larrin's book came out).
 
If you're wanting even more hardness, maybe look into zmax?

Someone else mentioned k390, which I think could be pretty good for that kind of knife.
 
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