Shootout: M390 vs S90V CF Military's Edge retention on 5/8" Manila rope

Ankerson

Ankerson

Knife and Computer Geek
Joined
Nov 2, 2002
Messages
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Been wanting to do this for awhile, a direct straight edge retention comparison between these two steels. They are very close in performance, closer than some would believe. Both knives are CF Sprint run Military's sharpened to 400 grit Congress Moldmaster finish at 15 degrees per side. This leaves IMO the optimal edge finish for maximum edge retention and cutting efficiency.

The Test:

Slicing 5/8" Manila rope checking every 20 cuts for down force and cutting was continued until 20 LBS was reached. Starting force was 11 LBS for both knives and after 20 cuts both knives were at 14 LBS.

The Steels:

M390

C - 1.9%
Mo - 1.0%
Si - .70%
W - .60%
Cr - 20%
Mn - .30%
V - 4.0%

CPM S90V

C - 2.30%
Mo - 1.0%
Cr - 14.0%
V - 9.0%

M390

Cut aggressive with the edge finish and took some edge damage as expected as all steels have, it was still sharp enough to slice printer paper after testing.

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CPM S90V

Very Aggressive with the edge finish and as with M390 it took some edge damage, but slightly less. Sharp enough to slice printer paper after testing.

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Knives together.

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Results:

Both knives performed extremely well as expected with S90V over M390 in the end by 21% or 460 to 380 cuts.

Very close as I expected it to be, under normal use most wouldn't be able to tell them apart depending on actual use unless they were pushed to the limit of edge retention. In that case the added Vanadium content of S90V at 9% over M390 at 4% would take over.
 
Very interesting, thanks.

Do you think there is an appreciable difference in ease of sharpening?
 
xavierdoc said:
Very interesting, thanks.

Do you think there is an appreciable difference in ease of sharpening?
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I would say M390 is easier due to the lower Vanadium content, takes less time.

Both steels are loaded with carbides though, so VG-10 they aren't. :D
 
That is great. I have been wondering how the two would compare. Been wanting to make some more stainless knives and guess I will go with more S90V.

Thanks for the time to do this evaluation, it answers curiosities.

Chris
 
Big Chris said:
That is great. I have been wondering how the two would compare. Been wanting to make some more stainless knives and guess I will go with more S90V.

Thanks for the time to do this evaluation, it answers curiosities.

Chris
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Can't really lose with either, both are great, but S90V has the edge at the same hardness.
 
Could you tell us what a "400 grit Congress Moldmaster finish " is?
 
Jim,

Thanks again for another great test! When I was testing my S90V Millie (slightly different test), at the end of my test, the S90V just seemed like it would keep cutting and cutting. The M390 (and CTS-204P) just didn't have the same "bite" as the S90V.

I guess all those Vanadium carbide do something after all ;).
 
MVF said:
Could you tell us what a "400 grit Congress Moldmaster finish " is?
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The Congress moldmasters are hard Silicon carbide that leaves a semi polished edge.

Gunsnknives said:
Jim,

Thanks again for another great test! When I was testing my S90V Millie (slightly different test), at the end of my test, the S90V just seemed like it would keep cutting and cutting. The M390 (and CTS-204P) just didn't have the same "bite" as the S90V.

I guess all those Vanadium carbide do something after all ;).
Click to expand...

I pushed these to the limit, both knives were almost to that point of not cutting paper after testing.

sodak said:
Great stuff, thanks! Now I'll know what to expect from my new Southfork! :D
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The South Fork really performs. :D
 
One more question...how did these perform with the 400 grit finish as compared to your steel ranking test with the 6000 grit finish? I guess we have to assume the M390 mule is comparable to the Military.

Thanks!
 
Gunsnknives said:
One more question...how did these perform with the 400 grit finish as compared to your steel ranking test with the 6000 grit finish? I guess we have to assume the M390 mule is comparable to the Military.

Thanks!
Click to expand...

Nope, not the same, they cut a lot longer with the 400 grit finish.

Won't know until I get it back from hardness testing.
 
Jim, thanks for taking the time to run the test, and post it here. I like your particular style of testing and can follow it without going off on tangents and trying to look up other published stuff to see if the names dropped were in fact relevant to this particular test. :)

The M390-S90V head to head was one a lot of us wanted to see.

I still would like to get you the cruwear mule for you to fit in when you get time. I'll be glad to buy some rope for you too with a donation as you know better what to get.

Thanks again,

Joe
 
Thanks for this great test Ankerson. I' ve been a long time lurker here on the forum and always enjoyed your tests, keep up the good work:)
 
Buffalohump said:
Jim - you the man! Now all you need to do is add Elmax to this and we'll have it all! :D
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The ELMAX was at 58.5 HRC that I tested (Mule and same coarse edge) so there was a difference from what it will do at 60 HRC, not really fair to compare them at this point as the difference is larger than it would be.

Normally comparing M390 to ELMAX, both at 62 HRC there is about a 20% difference.
 
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Got the HRC hardness results back on the M390 Military, came in at 61 HRC, the S90V Military is 60 HRC.
 
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