Benchmade 20cv Isses

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Sean2989

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Mar 12, 2017
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So I bought a 940-1501 used for Christmas and what a knife it is, being my first 940 I have really had nothing else in my pocket since then. I had a nagging feeling about the blade, 20cv being almost identical to M390, I felt there was something wrong. No matter what angle or be it toothy or polished I just couldn't get it perform anything close to my other M390 knife. So recently I had the hardness tested and it came out at 52 but it was toward the top of the blade though. Maybe someone could tell me if the hardness is the same throughout the blade or it get softer as it gets closer to the spine? Then what sort of edge retention should I expect at 52? Thanks!
 
It's not differentially hardened. That would be rare for a folder or any production knife.
52 RC is extremely low. Where did you get it tested? Would also like to see a pic of the blade with the mark from testing or other documentation.
Anyway, you would want to send it in to warranty with documentation from your testing.
Welcome to Bladeforums. Just so ya know - there are manufacturer specific boards. Benchmade has their own forum on this site.
 
Don’t know what the hardness is on my 20cv Grip, but no issues here. It holds a great edge and is fairly tough...has been better than ZT 204cp or Spyderco M30 (blue from Bento, still working with the Red M390 from DLT).
 
940-1401 was the knife that convinced me of the beauty in 20CV. There was no way mine was 52 RC though.
It’s real thick behind the edge, I definetaly had to reprofile mine to get some real use out of it.
 
I am curious on how you tested it. Do you have access to one of the Rockwell hardness testing machines? I haven't been able to play with one yet and have been dying to know if an inclined surface would give a false reading due to be indented obliquely relative to a piece the same hardness with parallel flats.
Have you tried an alternative test, like a scratch test? A file should bite with noticeable disparity if zoning is present.
 
Yes - picture and test documentation or it never happened. OP - I do hope your first post on Bladeforums does contain accurate information.
 
I by no means am a expert, but as others have stated 52 Rockwell is extremely low. Most manufactures have a rating of about 58-60 on the “low side” and 60-62 on the “high side”.
 
I have several BM CPM 20 blades all have proven awesome. Maybe your testing isn’t off or you just got a bad blade.
 
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Okay to answer to a few questions, I work in a machine so I gave the knife to our head inspector and he tested it 3 time to make sure he wasn't getting false readings. It tested at 51.9, 52, 52 for each test. I will post a picture or two so you can see. I didn't try the scratch test because with the three readings all being more less the same, but I will give it a shot. Maybe I did just get a bad blade because my Kershaw dividend in M390 is an amazing blade. I just hate the 6-7 week turnaround from Benchmade.
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Thanks for the photo. Did you level the blade? My understanding is that you're supposed to test on the flat or tang for a more reliable reading.
 
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AF said:
Thanks for the photo. Did you level the blade? My understanding is that you're supposed to test on the flat or tang for a more reliable reading.
Click to expand...
Should also be on the thickest part of the blade to eliminate possibilities of blade flex corrupting the test results. That location in your photo doesn't seem like the ideal spot to do a hardness test.
Puma does a hardness test of every blade they sell with a sticker that explains the little punch mark in your blade. Their test seems to always be back towards the pivot or bolster from what I have seen.
 
AF said:
Thanks for the photo. Did you level the blade? My understanding is that you're supposed to test on the flat or tang for a more reliable reading.
Click to expand...

Correct, you can't get an accurate reading on the blade bevel. You need to check the hardness on a flat surface.
 
Just send the dude back to Benchmade, explain your concerns and let them put a new blade on it. Seems like the easiest and most definitive solution.
 
Sean2989 said:
I just couldn't get it perform anything close to my other M390 knife. So recently I had the hardness tested and it came out at 52... Maybe someone could tell me if the hardness is the same throughout the blade or it get softer as it gets closer to the spine? Then what sort of edge retention should I expect at 52? Thanks!
Click to expand...
Significant difference in performance is a telling tale for me, as my 2 Benchmade m390 blades are comparable to my Benchmade 940-1501. I chalk up any various minor differences to geometry between my 710 and 810, both 1401's and the 20cv blade. Running all of them at 40 degrees inclusive off KME 1500 and DMT EEF (~4micron), which means I touchup on Sharpmarker medium stones with raging success. Seriously happy with this class of steels. Just gifted my second BM S30v blade, this time as an xmas present for one of the sons, a mini-ruckus, so we get to compare notes on durability of the edges. (just check notes 940-1501 is at 38 degrees and has only been stopped with levis)
 
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