M2 Steel knife abusive testing (M2 is not as brittle as some think)

L

Londinium Armoury

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Jun 2, 2020
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I noticed some old threads on bladeforums dating back to 2011 of people asking if M2 is brittle at 66 HRC. I have just made a knife out of M2 stock that is running at 65-66 HRC, made from a decent all hard power saw blade (not Bi-metal) using water coolant and grinders to remove stock.
I stabbed into hardwood and twisted the blade on its accute tip, I used pry techniques on the wood, and then went onto cutting into a round steel pipe.
The results are zero edge deformation, no chipping, no rolling, it just made the knife slightly duller, but did not disturb the apex at all.
So I thought this would be some good info to share with you all, I think people have the impression that M2 is not tough, and will break under hard use.
This knife has a slightly convexed appleseed grind that is taken back just under scandi depth. You can check out the video I recorded of the unedited demonstration here. it is 2.5mm Thick with a "Self yew" 2 tone wood handle.
 
I love that stuff. Do you have a source for the M2? I have 2 big blades left, like 2' long, 2" wide and maybe 3/32" thick. Grinding that stuff sucks, but it's worth it in the end. I used a small blade as a throwing knife by accident. It hit a piece of steel and didn't affect the tip.
 
me2 said:
I love that stuff. Do you have a source for the M2? I have 2 big blades left, like 2' long, 2" wide and maybe 3/32" thick. Grinding that stuff sucks, but it's worth it in the end. I used a small blade as a throwing knife by accident. It hit a piece of steel and didn't affect the tip.
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I'm buying it pre hardened from Eclipse tool company, made in Sheffied UK. I use the large size power saw blades, ALL HARD version. If you search on ebay "Eclipse all hard saw blade" you will find lots of different size ones. I recommend getting the 2.5mm thick ones made for electric power saws, not the smaller thinner hand saw ones. The 2.5 mm ones with larger teeth don't bend and are very rigid, they do Bi-metal ones as well so watch out that you buy the right kind, they come in various thickness, anything 2mm+ should be rigid enough.
Here is the exact title of the item I bought but this size from the same brand seems out of stock.
Eclipse Power Hacksaw Blade 4 tpi 23" - 2 - 100 575mm - 50 - 2.5 All Hard HSS
There are other brands witht he same specs though in M2 still like the AVEN ones etc. If you use the flat side to grind the bevels on the edge it's better, then get an angle grinder flap disc to grind down the saw teeth, and if you get them down just right they turn into very attractive jimping squares that look quite good. I made a better knife out of the other half of the saw blade.
Hope this helps.
 
Sounds good. I had these gifted to me and haven't looked for more since then. Edge holding is excellent. I have a kitchen knife blade ready for a handle and want to make a matching larger one. The current one is only a 2.5" blade.
 
me2 said:
I love that stuff. Do you have a source for the M2? I have 2 big blades left, like 2' long, 2" wide and maybe 3/32" thick. Grinding that stuff sucks, but it's worth it in the end. I used a small blade as a throwing knife by accident. It hit a piece of steel and didn't affect the tip.
Click to expand...
me2 said:
Sounds good. I had these gifted to me and haven't looked for more since then. Edge holding is excellent. I have a kitchen knife blade ready for a handle and want to make a matching larger one. The current one is only a 2.5" blade.
Click to expand...
Nice one, the edge retention is unreal, surprisingly tough for such a hard steel, honestly I thought it would be chippy at such high HRC but it's not at all. M2 is great stuff, I'm surprized more companies aren't using it, it's not expensive to buy and is harder and tougher than lots of other stuff out there.
 
The heat treatment procedure for these is quite different than that used for knives. I wish someone make production knives with a saw blade heat treatment. Don't get me wrong, I think one would have to be crazy to make a large chopper out of this stuff, but for the stuff I use it for, it has worked very well. Granted that only like 3 knives, but still.
 
I see in your video you mention using it for choppers. I would recommend against that. It is tougher than I would have ever expected, but nothing like what I'd want in a chopper. I had 3 large saw blades and was cutting out the knife I currently need to finish, along with some other shapes. I dropped one and it broke. The other I just couldn't cut properly and ended up scrapping it. I'd limit these to 5 to 7 inch blades max or limit them to very specific duty. I briefly considered a 12" blade dedicated to cutting demos on rolled newspaper, water bottles, cardboard tubes and such. Then I figured i would eventually try something more just to see what would happen and that would be the end of me.
 
me2 said:
I see in your video you mention using it for choppers. I would recommend against that. It is tougher than I would have ever expected, but nothing like what I'd want in a chopper. I had 3 large saw blades and was cutting out the knife I currently need to finish, along with some other shapes. I dropped one and it broke. The other I just couldn't cut properly and ended up scrapping it. I'd limit these to 5 to 7 inch blades max or limit them to very specific duty. I briefly considered a 12" blade dedicated to cutting demos on rolled newspaper, water bottles, cardboard tubes and such. Then I figured i would eventually try something more just to see what would happen and that would be the end of me.
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I know what you mean, it would seem better suited to small cutting blades, but I figured with a robust appleseed convex grind it would hold up well. It's held up to batoning with a steel hammer, the spine doesn't even dent like most of my other blades I baton with. I use a D2 bowie knife to baton with and the spine has tons of dents and rolling down it from 2 years of batoning splitting forge charcoals. This M2 blade didn't even budge it held up like a champ.
I made an even bigger chopper double the size of this one just to see how crazy it can get. I'm doing all of these tests just so I can be confident in selling blades out of the stuff.
At first I was seriously expecting the tip to snap off while prying wood, and the edge to chip during heavy chopping into hardwood. I expected complete catastrophic failure when chopping into steel pipe. But surprizingly it's still undamaged.
I honestly think M2 is quite tough stuff, I think it's due to it's relatively low carbon content for such high HRC. Steels with around 64-66 HRC usually have double the amount of carbon than M2, but this M2 barely has 1%, it's just due to its super quenching at 2200 degrees, then tempwering at 1050 degrees that give it this HRC points.
I would imagine if this had over 2-3% Carbon we would be seeing way more chipping, as steels with this level of HRC usually have over 2.5% carbon like ZDP or Maxamet, I would guess those steels would crack and chip.
I made a blade called the M2 Rose it's huge, you can check it out here, https://www.etsy.com/uk/search?q=londinium armoury
 
Londinium Armoury said:
I noticed some old threads on bladeforums dating back to 2011 of people asking if M2 is brittle at 66 HRC. I have just made a knife out of M2 stock that is running at 65-66 HRC, made from a decent all hard power saw blade (not Bi-metal) using water coolant and grinders to remove stock.
I stabbed into hardwood and twisted the blade on its accute tip, I used pry techniques on the wood, and then went onto cutting into a round steel pipe.
The results are zero edge deformation, no chipping, no rolling, it just made the knife slightly duller, but did not disturb the apex at all.
So I thought this would be some good info to share with you all, I think people have the impression that M2 is not tough, and will break under hard use.
This knife has a slightly convexed appleseed grind that is taken back just under scandi depth. You can check out the video I recorded of the unedited demonstration here. it is 2.5mm Thick with a "Self yew" 2 tone wood handle.
Click to expand...
Londinium Armoury................. :)What you make is something that look like knife but it is not knife it is chisel :) With that angle tungsten carbide will not chip . I have made maybe more than a hundred knivs from M2 and other HSS steel .......I know that steel .I like it very much BUT it is not steel for hard use ......
This one is from 2mm M2 full flat grind and IF i try to cut that pipe..............it will fall apart into a thousand pieces...maybe in two thousand :D
m5OOJBW.jpg

FXcZTtT.jpg
 
Natlek said:
Londinium Armoury................. :)What you make is something that look like knife but it is not knife it is chisel :) With that angle tungsten carbide will not chip . I have made maybe more than a hundred knivs from M2 and other HSS steel .......I know that steel .I like it very much BUT it is not steel for hard use ......
This one is from 2mm M2 full flat grind and IF i try to cut that pipe..............it will fall apart into a thousand pieces...maybe in two thousand :D
m5OOJBW.jpg

FXcZTtT.jpg
Click to expand...
Well a knife doesn't have to have a specific grind, geometry and edge angle, if I'm making a knife for heavy duty chopping I will put a robust convex edge geometry on it, putting a thin behind the edge grind wouldn't make sense for a chopper. The two M2 knives I made can cleanly cut through papert towel and feather stick. I also make kitchen knives.
I made a Japanese Single bevel Usuba which would chip instantly if I tried to use it like a chopper because it's so thin behind the edge.

Not all knives have to be thin behind the edge to be called knives, heavy duty knives are supposed to be thick and robust otherwise they won't last many years of heavy duty use. Like the Hultafors Heavy duty knife, that has ridiculously thick grinds, and has a way shorter edge bevel than my M2 knife.
 
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Here Natlek, just to show you that this M2 knife and my other M2 Rose can cut and are very sharp. They are not thin knives theya re heavy duty choppers, but they are not slouches when it comes to razor edge cutting.
 
It might be tough enough in heavy geometries, but still not something I'd do. M2 treated the way these are is still very brittle compared to the usual large chopper steels. I have a chopper from S7 sitting on my bench I need to finish. Something like that or 8670, ESEE 1095, 5160, etc, would be my choice. I wouldn't even want A2 or 3V beyond about 8 or 9 inch blades.
 
me2 said:
It might be tough enough in heavy geometries, but still not something I'd do. M2 treated the way these are is still very brittle compared to the usual large chopper steels. I have a chopper from S7 sitting on my bench I need to finish. Something like that or 8670, ESEE 1095, 5160, etc, would be my choice. I wouldn't even want A2 or 3V beyond about 8 or 9 inch blades.
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Well those are shock resistant impact spring steels, I usually use CS95 for my big choppers, The only downside to all of those steels is they can't hold a sharp edge for long at all, I have been using spring steel blades for over 10 years for camping and hard use tasks. They are great for absorbing shock, but have terrible edge retention. This M4 blade can work 100 times longer without need of sharpening, and has stood up to every abusive test i've thrown at it so far. I don't think M2 is very brittle at all with a convex scandi grind. It would probably be brittle if it was taken to a typical plunge grind shallow full flat grind, but I'd never attempt such a grind with M2. S7 is good stuff it's really tough, just hasn't got enough carbon to compete in edge retention.
 
Fellow lover of M2 HSS here. Thanks for posting this, I have a couple gifted to me from a fellow forumite years ago that I use all the time in the garage for menial tasks, breaking down boxes, etc. Good stuff!
 
Edge holding and wear resistance aren't priorities for my choppers. They hit dirt, rocks, etc. What I can't have them do is break. I've had one do that before, and nearly got stabbed. M2 is great steel, but I can't bring myself to use it in a large general use chopper.
 
Not from that manufacturer but I also made a knife out of one of those thick (2,5mm) sawblades we are discussing here. I also put a short bevel on it with the belt grinder (dunking in water after each swipe) and so far it is working nicely as shop knife, cutting whatever needs to be cut.

I managed to drill through it with a sharpened tungsten carbide tipped drillbit and high rpm's. Not pretty, but it was meant for an epoxied pin anyways.

Great job on that blade!
 
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