knifeworks 710 M390.

din

din

Joined
Feb 16, 2006
Messages
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I just paid off the balance on this after I received the e-mail saying that they were starting to ship. anybody already have theirs? I'm getting super excited!
 
Got mine yesterday.
She's a beaut and sharpens a bit easier than my D2 710.
I'm in the process of stropping it to a mirror finish and I think it's going to take a while. Never stropped to a mirror finish before - gotta get at least one mirror finish in this lifetime.
All I know is that it got stupid sharp relatively quickly and the stropping is making it stupid, scary sharp.
I'm unsure what the ideal sharpening bevel is for the M390/710 combination, but I went with the lowest DMT aligner setting for the reprofile.
Seems to be okay, I gotta do some wood cutting tests to see if this super steel does well with this thin of a cutting edge.
 
mongomondo said:
Why did you sharpen it already? Was it dull from the factory?
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Production knives do not ship with a true polished edge, which is what Termiteslayer is working toward. Factory edges can be very good, but the true edge fiend wants better than that.
 
mongomondo said:
Why did you sharpen it already? Was it dull from the factory?
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I haven't met one factory edge that I've liked, though the 710 M390 was pretty sharp. Not very sharp, just pretty sharp.
The bevels weren't uniform or equal, not that the factory didn't do a halfway decent job. It just wasn't PERFECT!
Guess I'm just picky... whatever.
What matters is that I enjoy refining the edge.
 
termiteslayer said:
I haven't met one factory edge that I've liked, though the 710 M390 was pretty sharp. Not very sharp, just pretty sharp.
The bevels weren't uniform or equal, not that the factory didn't do a halfway decent job. It just wasn't PERFECT!
Guess I'm just picky... whatever.
What matters is that I enjoy refining the edge.
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You're not picky, you're just a guy who actually knows how to sharpen a knife. I'm in the same boat as you, I always here people compliment and complain about factory edges. Truth is, if you become proficient at sharpening you'll never be happy with any factory edge (regardless of company).
 
I was pondering one of these but I wasnt sure where M390 fits into the scheme of things. What CPM steel does it best compare to?
 
Bohler M390 steel is made using Bohler-Uddeholm MicroClean technology, form of PM. Latrobe and Carpenter also make PM versions of the same steel, using Duratech 20CV(Latrobe) and Micro-Melt 20-4p(Carpenter) names.
I've tried to find a similar CPM steel in the database, but 20% Chromium excludes everything right off the bat.
There's Cowry-X and ZDP-189 with that much Cr in them, but both have 3% Carbon, not 1.90 as M390 and clones do...
 
M390 is a wonderful steel. I've been carrying my Volt a lot, and it will polish up easily. It does compare closest to Cowery-X and ZDP as Gator mentioned. But I find it a lot easier to sharpen than ZDP. I have no experience with Cowery-X, so I can't comment on that one.
 
termiteslayer said:
I haven't met one factory edge that I've liked, though the 710 M390 was pretty sharp. Not very sharp, just pretty sharp.
The bevels weren't uniform or equal, not that the factory didn't do a halfway decent job. It just wasn't PERFECT!
Guess I'm just picky... whatever.
What matters is that I enjoy refining the edge.
Click to expand...

Your going to reprofile the knife with a strop? Wow, good luck...;)
 
Nope, DMT aligner just to make things uniform first.
I got the scratches as small as I could before I started stropping.
I've been stropping for hours and it looks like I got a ways to go to get the mirror finish.
Crap... and I was hoping it would be easy.
 
SPXTrader said:
M390 is a wonderful steel. I've been carrying my Volt a lot, and it will polish up easily. It does compare closest to Cowery-X and ZDP as Gator mentioned. But I find it a lot easier to sharpen than ZDP. I have no experience with Cowery-X, so I can't comment on that one.
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I believe ZDP-189 is HTed at a few higher RC points than M390. While M390 is different steel (& more stain resistant?), I thought it compared favorably with M4 steel. Of course, I could be wrong on that.

For those that liked & wanted the BM 710 M4, but didn't get one &/or can't afford the current prices of them now, the M390 version seems like a great way to go.
 
Nice, I was just considering getting it in D2 because I want a really wear-resistant steel, but I've wanted to try the M390 in the MPR for a while too.
 
CL01 said:
I believe ZDP-189 is HTed at a few higher RC points than M390. While M390 is different steel (& more stain resistant?), I thought it compared favorably with M4 steel. Of course, I could be wrong on that.

For those that liked & wanted the BM 710 M4, but didn't get one &/or can't afford the current prices of them now, the M390 version seems like a great way to go.
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Let me check on that. I have Kershaw's specs for M390 somewhere, and I believe they run ZDP at 64 - 66. Once I find the M390 Rc numbers, I'll put them up here. As for stain resistance, I still don't see where the complaints of ZDP are coming from. I've used my Acies in the kitchen a lot, with only a wipe down with a paper towel when finished. Still no staining or rust.
 
SPXTrader said:
Let me check on that. I have Kershaw's specs for M390 somewhere, and I believe they run ZDP at 64 - 66. Once I find the M390 Rc numbers, I'll put them up here. As for stain resistance, I still don't see where the complaints of ZDP are coming from. I've used my Acies in the kitchen a lot, with only a wipe down with a paper towel when finished. Still no staining or rust.
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Sorry, my stain resistant comment was in comparing M390 to M4, not to ZDP-189. ZDP is definitely rust/stain resistant. I was saying that M390 (Which I believe to be at about 60-62 RC) should be comparable to M4 (Which I believe is also at about 60-62 RC). M4, however, can rust, while I believe M390 is stain/rust resistant. ZDP-189 is typically in the mid 60s RC (I've seen it at anywhere from 63-67 RC), so M390 & M4 should be easier to sharpen than ZDP.

Based off of all that & if M390 is pretty comparable to M4, the new BM 710 M390 should be an excellent (& affordable) alternative to the 710 M4, I would think.
 
SPXTrader said:
M390 is a wonderful steel. I've been carrying my Volt a lot, and it will polish up easily. It does compare closest to Cowery-X and ZDP as Gator mentioned. But I find it a lot easier to sharpen than ZDP. I have no experience with Cowery-X, so I can't comment on that one.
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Like SPXTrader, I've also been carrying my Volt a lot, and I also have found the M390 steel to be very sharp. It is easily the sharpest knife I have received from the factory in that it will shave hair without touching skin. Kershaw really does a great job on their factory edges.:thumbup::)
 
termiteslayer said:
Nope, DMT aligner just to make things uniform first.
I got the scratches as small as I could before I started stropping.
I've been stropping for hours and it looks like I got a ways to go to get the mirror finish.
Crap... and I was hoping it would be easy.
Click to expand...

I just reprofiled a ZT 0301 with the DMT Magna Guide. I used HA 2 micron paste forever, then HA 1 micron, then HA .5 micron. Still had scratch marks.

I read knifenut1013's sharpening thread and went back over the heavily stropped blade with the xx-fine stone again lightly and it removed 99% of the scratches. Repeated the above procedure yesterday on the strops and I finally have a sick looking mirror edge. Very satisfying and my first one. :D
 
SPXTrader said:
...and I believe they run ZDP at 64 - 66. Once I find the M390 Rc numbers, I'll put them up here. As for stain resistance, I still don't see where the complaints of ZDP are coming from. I've used my Acies in the kitchen a lot, with only a wipe down with a paper towel when finished. Still no staining or rust.
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I've asked about Kershaw ZDP and specs were 63-64HRC. Which is plenty hard for factory folder.
As for the ZDP-189 rust issues, there are some if you treat ZDP-189 as any other stainless steel knife, because despite of 20% chromium it has, there's also 3% C in it, which ties up a lot of Cr, thus reducing stain resistance.
To illustrate, ZDP-189 vs. 440C steel composition comparison using atom counts per 1000.
Roughly speaking the difference in height of the C and Cr bars is your stain resistance, and for ZDP-189 that difference is a lot smaller.

And finally, rusted ZDPs in humid env, and unused one rusted worse:


Old thread about ZDP rust issues.
 
i confirm the rust resistance issue.

i had a big surprise the first time i disassembled my cf/zdp stretch. i had zero rust spot on the blade wich was well cared, but there was some severe piting just under the washers. now i also have some spots on the rounded par of the tang where the lockbar rests.

still one of my favorite edc.
 
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