Japanese High Carbon

[000Robert]

Marc H wrote:

Apology heard and accepted. We’re getting off the topic subject here, “Japanese H C” but… I’m confused by your characterization of your Buck knife’s steel as ” so hard”. My understanding is its 440HC SS at HRc 56-58. Which in today’s popular knife steels is just a moderately hard steel. I don’t consider a steel as “hard” until at least HRc 60. But that’s my personal delineation. Why you had difficulty sharpening it with the Pro Edge Tri Stone, I have no idea. I can only suggest, all whetstones are not the same. Some are better for harder steels others not so good. FYI: There are many blogs describing carbide breakout and other steel damage experienced using diamond sharpening stones. What I experienced and share is not a very rare situation. https://scienceofsharp.com/ and http://knifesteelnerds.com/ are a couple of these.

I know and that is what I thought about Buck steel. I never had a problem with any other pocketknife with my whetstones(maybe these should be called Oilstones). I think the steel in my Buck 301 somehow was hardened more than they normally are. But I don’t have a Rockwell tester to test it with.

I have read a lot of scienceofsharp and knifesteelnerds. I also have Dr. Larrin Thomas’ new book, “Knife Engineering”. I’m about midway through it. But for me personally, I would have a hard time thinking that the sharpening medium or method is wrong if I could not verify that the steel is what it is claimed to be. My first suspect would always be the steel and it’s heat treatment until I could prove that it wasn’t. From what I have learned this past year,  a steel is no better than it’s heat treat.

[Marc H]

The only place I look when I’m having difficulty sharpening any knife is right back at me.  As long as I can clamp it up I haven’t come across a knife or knife steel yet that I couldn’t sharpen to my liking with the W.E. once I found the balance between the proper sharpening technique to apply and the appropriate sharpening medium to employ.  Sometimes my first sharpening experience with a new steel can be trying and often time consuming.  I never even thought that a knife steel might be anything other then it’s specified.

Marc
(MarcH's Rack-Its)

[000Robert]

I guess I’ll just have to get a couple of those Japanese knives to better understand what’s going on. Getting some hardness testing files might be good to at least get a general idea of where the hardness of a blade is.

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Brewbear

[000Robert]

I just ordered a 6 piece set of hardness testing files that are made in Japan. I will get an idea of how hard the steel in my 301 is. I was planning on getting a set and forgot about it. This thread reminded me. Thanks.

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Brewbear

[000Robert]

Hi guys. I just received my Tsubosan Hardness Tester Files. On my Buck 301 blades the 65 file will bite, but the 60 skates across. On my Kershaw Launch 1 that has CPM-154 steel the 60 file will bite, but the 55 skates. So I guess that somehow the 425M steel in my 1990 Buck 301 was hardened harder than it was supposed to be.

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Brewbear, NotSharpEnuff, tcmeyer

[tcmeyer]

Thanks for the post, Robert.  I ordered a set of the files today.  I hope to use them on blades I harden in my propane mini-forge.

I’ve always noticed that the stainless knives I’ve sharpened in 420C and 440C “felt” different.  Not hard, but resistant to normal abrasion by my diamond stones.  I think I’ve sensed something similar on other manual sharpening stones, like the Spyderco Sharpmaker and my Arkansas stones.  It’s as if the surface of the steel would rather “smear” than be cut cleanly by the grit.  On thinking that over, I wonder if that means that it lends itself more to stropping, which I think is a similar process.

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Brewbear, 000Robert

[000Robert]

tcmeyer wrote:

Thanks for the post, Robert. I ordered a set of the files today. I hope to use them on blades I harden in my propane mini-forge. I’ve always noticed that the stainless knives I’ve sharpened in 420C and 440C “felt” different. Not hard, but resistant to normal abrasion by my diamond stones. I think I’ve sensed something similar on other manual sharpening stones, like the Spyderco Sharpmaker and my Arkansas stones. It’s as if the surface of the steel would rather “smear” than be cut cleanly by the grit. On thinking that over, I wonder if that means that it lends itself more to stropping, which I think is a similar process.

I’m not sure. I’m learning myself and don’t know much about it. I checked Blade HQ where I bought my Launch 1 at and the Rc number for the steel wasn’t mentioned. According to the Kershaw website, their CPM-154 is Rc rated at 58-60. That pretty much goes with my findings with the files. So I’m confident that the files are pretty accurate. I can at least get a reasonable estimate to the hardness of a steel. Being a hobbyist I don’t really need to know the exact Rc number.

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Brewbear

[Brewbear]

Your Japanese is better than mine! Thank you for posting your findings, much like you I collect knives I like and the precise Rc rating is not the determining factor. From the little reading I’ve done, Buck has a proprietary (I believe) hardening procedure that they use on their blades.

[000Robert]

You’re welcome. I don’t know any Japanese. I just go by the numbers.

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Brewbear

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