BM m390 heat treatment

F

Folding

Joined
Feb 9, 2015
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35
I noticed that m390 on my Valet does not feel as hard as I expected for 60+ HRC.
(although to give it credit, it holds the edge great)

Has anyone tested their m390 blades from BM for hardness?...

Thanks.
 
I've had benchmades d2 tested and it was spot on with what they spec, I know it's not m390, but they nailed the d2. I wonder if it's recent batches, I could always swing by the heat treaters and have him test my m390 contego.
 
Hi Jastab,

reading the threads about m390, I feel there are at least a few people who would find the m390 number interesting!

Especially given that getting BM to do the m390 test mentioned in the other thread went nowhere...
 
What do you mean it doesn't feel as hard? How are you testing it? You mean by pinching it with your fingers?
 
jtoler_9 said:
What do you mean it doesn't feel as hard? How are you testing it? You mean by pinching it with your fingers?
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I have two knives in XHP at 60-61 HRC. Both leave scratch marks on m390 very easily, but m390 cannot scratch either. This is Mohs hardness test and it says m390 is softer than 60-61.

Strangely, I see a remarkable edge retention in m390, at least as good as XHP and probably even better.
 
Folding said:
I have two knives in XHP at 60-61 HRC. Both leave scratch marks on m390 very easily, but m390 cannot scratch either. This is Mohs hardness test and it says m390 is softer than 60-61.

Strangely, I see a remarkable edge retention in m390, at least as good as XHP and probably even better.
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Mohs hardness is not the same as Rc hardness testing, and since you're comparing apples and oranges, I doubt it will really tell you anything.
 
loonybin said:
Mohs hardness is not the same as Rc hardness testing, and since you're comparing apples and oranges, I doubt it will really tell you anything.
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re: "apples and oranges",
One holds a hot spoon, then a cold spoon. One tells "first spoon is hotter" and
asks "does anyone have a thermometer to tell how much oF is each spoon?".

You comment:
"Skin sensation is not the same as oF measurement, and since you're comparing apples and oranges, I doubt it will really tell you anything."
 
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Jastab said:
I've had benchmades d2 tested and it was spot on with what they spec, I know it's not m390, but they nailed the d2. I wonder if it's recent batches, I could always swing by the heat treaters and have him test my m390 contego.
Click to expand...

I'd be interested in the results of that. It sure would put the discussions into a much more realistic context.
 
I'm interested to know as well. I have not had a problem with my Ritter's.
 
John_0917 said:
Officially, according to the 2015 catalog, BM's M390 should be hardened to 62-64 HRc.
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The catalog doesn't say anything about M390 being hardened to 62-64HRC.

Folding said:
I have two knives in XHP at 60-61 HRC. Both leave scratch marks on m390 very easily, but m390 cannot scratch either. This is Mohs hardness test and it says m390 is softer than 60-61.
Click to expand...

Actually, since you aren't using an HRC tester, that's not what it says at all. Benchmades M390 is hardened to 60-62 HRC to be within spec. That could mean the HRC is 60, 60.5, 61, 61.5, or 62. The knives you have listed with CTS-XHP are supposed to be at 60-61 HRC to be within spec. So that could mean they are anywhere from 60, 60.5, or 61. Who's to say that your Benchmade in M390 isn't at 60.5 HRC, while both your blades from the other manufactures are at a 61 HRC? That would explain your results, and would explain why you aren't having any issues with edge retention. It terms of performance, HRC means different things for different steels, so comparing two completely different steels based on only on hardness doesn't really make much sense. Just because one steel is harder than another doesn't mean it's going to perform better in every way, and vise versa. Most of the time there's a trade off in terms of corrosion resistance, toughness, edge retention, and many other things when you're treating knives to a higher or lower HRC. Your best bet is to send it someone to be properly tested if you're really that worried about it. Until that happens, everything else is just speculation. You said it holds an edge great, as it should, so I don't really see the point in worrying about it. It would be different if you had a complete dud like Jason B, who is the person that started the other thread linked on this one. If I were you, I would just use it any enjoy it. :)
 
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RevDevil said:
I'd be interested in the results of that. It sure would put the discussions into a much more realistic context.
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I'll see if I can swing by the heat treaters this upcoming week, he does spyderco's ht for their golden knives, so I know know know he is legit. Don is awesome.
 
So you're saying that it has excellent edge retention and works great, but you still absolutely need some technical spec just to feel satisfied?

Whatever makes you feel warm and fuzzy bro:rolleyes:


What happens if you test it and it comes back under 60? Are you going to violently thrust it away exclaiming "I cannot use this inferior scrap of mortal steel!" and never use it again even though you've already seen that it works fine?
 
I can't believe that the OP deliberately scratched his blade with another blade just to see if it would leave a mark. But to each his own.
 
No matter which way you scratch it, there's a perception that something's wrong with the HT on the M390 blades. Too bad, I was going to buy a 485, but we'll see how this works out first.
 
Folding said:
If somehow this is not obvious--next step will be to get a true 62 HRC m390 knife. From another vendor.
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Do whatever you like bro.

But IMO, shunning a knife even though you've already seen that it works perfectly is highly irrational. Nothing will have changed if it comes back lower than expected.
 
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