CPM-3V vs M4 vs K390 for Katana??

T

tekaefixe

Joined
Aug 27, 2014
Messages
10
Hello everyone!

I’m going to order a Katana from Evolution Blades. For those of you who doesn’t know, it’s a company that specializes in blades for cutting. The top line is made of 3V and M4 steel and all steels are heat treated (no fancy hamon here).
My katana will have a hard target cutting geometry (will cut green and yellow(dry) bamboo.

I know 3V is tougher and M4 has better edge retention. Can it be that a katana made of K390 would be the bridge between V3 toughness and M4 edge retention? Or would K390 be too brittle (because it’s a bit harder than M4)?
What do you guys suggest I go for?
By the way, I don’t have the skill or the time to sharp the sword meaning I will never do anything else but cut once or twice a month with it.

Thanks for much for you inputs guys!

Cheers!


P.S - even though K390 is not a steel Evolution Katanas uses now, the owner is always trying new stuff and I’m sure it could be easily added.
 
Last edited:
3V makes the most sense to me. I have no sword cutting skills or ability though. I’m sure M4 in the hands of a pro would / could be ideal. M4 survives in chopping competitions, but 3V survives chopping through cement ( depending on heat treatment ).

I’m NOT an expert

I’d go for 3v though.

I should also apologize for cluttering the thread - I know next to nothing about swords.

I do have quite a few knives in M4 and 3V. M4 cuts for days, takes days to sharpen also ( when needed , which is rare ). 3V is easily maintained, takes a beating and is surprisingly stain resistant.
 
Last edited:
I agree with 3V. It’s one of the toughest steels there are that can retain an edge. Regarding M4 and K390….all the reviews I read say that K390 is harder, retains better edge, it’s tougher and rusts less. Is that really so?
 
Hard to say. Someone will have an answer though. I think a lot of it comes down to heat treatment. I’ve seen M4 cut through steel nails without edge damage from one maker, and chip out entirely from another maker. K390 is definitely not something I’m too familiar with, other than smaller knives seem to do great with it.
 
Yes.. it’s something to be aware of, this is for a long ass blade….it can’t bend, chip or dent (when used normally of course).
 
I would suggest that the heat treat is more important than the steel used. You also don't want to be the guinea pig for someone learning about a new to them steel. Finally I would suggest for most users you won't be able to tell a dimes worth of difference between any well heat treated carbon steel.
 
Triton said:
I would suggest that the heat treat is more important than the steel used. You also don't want to be the guinea pig for someone learning about a new to them steel. Finally I would suggest for most users you won't be able to tell a dimes worth of difference between any well heat treated carbon steel.
Click to expand...
Not quite so. Many Nihonto and industrial blades bend a even brake with bad cuts (wrong angle or when it hits the hard wood that supports the bamboo mats).
 
tekaefixe said:
Not quite so. Many Nihonto and industrial blades bend a even brake with bad cuts (wrong angle or when it hits the hard wood that supports the bamboo mats).
Click to expand...
That's certainly true and it will be true no matter what steel is selected if the heat treat is inadequate or technique is horrendous. In short material used does not overcome construction or lack of training. We often go looking for the magic bullet or steel but usually discover it doesn't exist.
 
The major cutting ability loss in such item would be due to edge deformation so you do not need high abrasion resistance steels like M4 or K390. You need a durable edge which will not chip and roll. In other words you need high impact toughness and edge strength. So you need a relatively low alloy steel which will get hard without sacrificing most of it's toughness.

3V has high impact toughness but doe not get harder than 60-60.5 without loosing significant amount of toughness. Blade competitions showed that 4V (or previously M4) at 64 HRC is a good performer, but the competitors are skillfull and they know how to use the blades properly. In blade competitions the blade length is limited to 10 inches which makes them less prone to damage and they are inherently easier to use unlike much larger katana. So, unless you are very good or the maker compensate the lack of edge durability (or user incompetence) with a thicker cutting geometry, I would suggest to go for much simpler steel, such as 52100, 80CRV2 or A8Mod. If the maker is confident the edge would hold up (when used by unprofessional, which basically means that the geometry is thicker than it supposed to be), among those three steels I would choose M4.
 
Last edited:
tekaefixe said:
My katana will have a hard target cutting geometry (will cut green and yellow(dry) bamboo.

P.S - even though K390 is not a steel Evolution Katanas uses now, the owner is always trying new stuff and I’m sure it could be easily added.
Click to expand...

I wouldn't be Guinea pig for a maker to try out a new steel.

I love 3V, but because you mentioned yellow bamboo I might prefer M4 if I were you (because it's harder).

Roland.
 
A sword is not a knife. Make it nice and chunky and you will be cut to ribbons by an opponent with a properly designed sword. Use a nice sword improperly and it will break. The sword is a precision tool designed for a well trained user.

n2s
 
not2sharp said:
A sword is not a knife. Make it nice and chunky and you will be cut to ribbons by an opponent with a properly designed sword. Use a nice sword improperly and it will break. The sword is a precision tool designed for a well trained user.

n2s
Click to expand...
This. Well said.
 
CPM3V

All day every day in a sword application.


Any doubts as to what CPM3V is capable of in sword form, take a gander at Dan Keffler testing his CPM3V swords against trees.

There are some awesome videos on YouTube.

Even at 60hrc it is nearly as tough as 5160. 40 ftlbs vs about 45 for 5160.


Cpm4v is at about 15 ftlbs at 61 hrc...
 
You must log in or register to reply here.
Back
Top