O1 Tool Steel 15-degree edge retention question

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rockfishbrewery

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Jan 24, 2012
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Hello,

Will O1 tool steel (properly heat treated of course) hold a 15-degree edge @60RC without being "chippy"? I'm currently working on doing a stock removal 6" chefs knife, and am trying to figure out which steel to use.

I ask because I recently purchased a Japanese santoku knife (Miyabi) of the following spec:

1) It was made with VG-10 stainless steel.
2) Hardened to 60RC
3) Had a 15-degree edge

I babied the knife from day one, and it developed several chips on the blade after two weeks of use (nightly family vegetable prep). I really liked how well the 15-degree edge cut, and am looking for a steel that will hold a 15-degree edge @60RC without being chippy. Will O1 fit the bill here? If not, what would you recommend?

I understand that O1 is not stainless, and I don't mind (since I religiously maintain my kitchen knives anyways).

Thanks in advance for any input you may have.
 
Sounds a little thin to me, but I think a convex edge on some .045" thick 15n20 will slice better than most kitchen knives you have used.

I am a little surprised you got chipping on that edge, but I tend to favor slightly softer steels for kitchen use with Aus-8 being one I really enjoy using. I also use a ceramic hone regularly on all my knives. 440C is another great kitchen knife steel that will hold up well.

Plenty of choices out there to do what you want.


-Xander
 
I have a santoku with VG-10 core, and while I like it, it will chip easily too. You should find O1 to be much tougher at 60 Rc. By 15 degrees, do you mean total angle (7.5 per side) or each side (30 degrees total)? The former is a bit anorexic, the latter OKish. But, it depends on how thick your edge is to begin with. A 30 deg. total edge will cut with a lot less drag if the edge is .010" before sharpening than if it's .030" before sharpening.

W2 or CruForgeV would do a nice job...
 
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Also, what is your cutting board made of? Hopefully wood or at least plastic, marble and glass are horrible on knives. Or, maybe someone put the knife in a drawer, sharpened it with a steel, or otherwise marginally abused it? VG10 may be chippy, but just cutting vegetables shouldn't do that to it.
 
I agree with Salem, the cutting surface is what I'd look at first. Proper cutting boards are wood/bamboo. How are you sharpening that edge bevel on there? The thinner your bevel gets, the more heat sensitive it will be to any sort of power tool. I don't even like to use loaded leather belts on a grinder if the edge is finer than 10-12 degrees per side.
 
Hello,

I have a bamboo cutting board, and wouldn't even think of not using a good cutting board.

Admittedly I am a noob, and don't exactly know what sharpening angle I need. The salesman at the knife shop I went to said that Miyabi had a 15-degree angle on it. I wish to duplicate that "15-degree" edge on the knife I am making.

When a knife salesman says "15-degree edge", what do they mean? Are they referring to a total angle edge, or a one-side edge?

Again, thanks for coddling a noob.
 
Re-sharpen your existing VG-10 blade with a steeper angle. Try it for a while, and change the angle as needed until you get the edge that holds up. When you get what works best, use that to make your next knife. You may want to try making the edge convex.

O-1 will work for your Santoku. 3V will be really tough, but a bit toothier. I have had good results with CPMS35VN. And it comes in thin stock from Aldo.

You have to find the angle and method of sharpening that works for YOU. I have had chefs order a knife with an unsharpened edge. That way they can put THEIR edge on it , and will be able to maintain the edge consistently.

Is there any reason you are set on Rc60? Drop that just a point or two and the knife edge may hold up much better for a vegi chopper. On a meat/fish slicer the harder edge may have some value, but on a chopper, I would go a bit lower, and get tougher. Sharpness has nothing to do with hardness.

Final note, there is no way to know what the actual edge hardness of your "chippy" VG-10 blade really is. They are batch hardened and tempered in a factory. An average is Rc60. I find that most of the VG10 blades I deal with seem over-hardened at the edge. When you do your own HT, or have it done by a good HT firm, you can test the blade and have a much better guess of the edge hardness.
 
I put a 15 degree chisel grind on leather paring knives made with O-1. They are specialty tools and not used for chopping, but at 58HRC they will pass a brass rod test.

Wayne
 
According to the true fanatics, bamboo is NOT a good cutting board. The glue that they use to stick them together is apparently very hard when it dries. As for your question, guys like Del Ealy make chefs knives from O1 with VERY Thin edges and angles no greater than 15%. 15 is pretty standard from factory kitchen knives from what I have seen, at least the decent ones. As for hardness, kitchen knives are different. Most kitchen knife fanatics might consider O1 at 60 RC to be about as SOFT as you should ever go. A bit different than the hunting knife world.
rockfishbrewery said:
Hello,

I have a bamboo cutting board, and wouldn't even think of not using a good cutting board.
Admittedly I am a noob, and don't exactly know what sharpening angle I need. The salesman at the knife shop I went to said that Miyabi had a 15-degree angle on it. I wish to duplicate that "15-degree" edge on the knife I am making.

When a knife salesman says "15-degree edge", what do they mean? Are they referring to a total angle edge, or a one-side edge?

Again, thanks for coddling a noob.
Click to expand...
 
jdm61 said:
According to the true fanatics, bamboo is NOT a good cutting board. The glue that they use to stick them together is apparently very hard when it dries. As for your question, guys like Del Ealy make chefs knives from O1 with VERY Thin edges and angles no greater than 15%. 15 is pretty standard from factory kitchen knives from what I have seen, at least the decent ones. As for hardness, kitchen knives are different. Most kitchen knife fanatics might consider O1 at 60 RC to be about as SOFT as you should ever go. A bit different than the hunting knife world.
Click to expand...
Are you talking about 30 degrees inclusive or 15 degrees inclusive?
 
VG10 is a chippy steel, as to where O-1 is not. I have both, have changed the angle on the VG10 and it will still chip. I have an O-1 gyuto that has never chipped at all and sits at about 61-62. O-1 will be a good steel, just make sure to wash and dry it as soon as you are done or it will rust as you watch it. I think what you are saying is a 15 degree bevel per side, giving a total of 30 degrees. That is what my gyuto is(O-1) and it is at .006 behind the bevel and i abuse the hell out of it and it holds up pretty well. I would say HT it first, grind slowly and take it to about .010 at the edge...maybe a touch thinner and progress on water stones. My stone progression is 500/1200/6000 deburring in between every stone and then strop on leather with a 1micron diamond spray. I can push cut tomatoes pretty effortlessly. Just be careful...Your fingers are no different than you food items in your knife's eyes :)
 
Hello,

I just called the knife distributor where I purchased my Miyabi santoku. They said that it has a 15-degree-per-side edge, which would make it 30-degrees all inclusive.

I'm most likely going to go with O1 steel for this build. Anything else I should consider?

Edit: I just saw Mike Davis's post. Thanks for the info :). I'm going to move forward with O1 steel.
 
I have used O1 on a thin blades at 15 degrees (each side) and it works very well, never seen a chip. My preferred shop knife is 1/8 full flat grind at 15 degrees and it has never chipped, I think it is close to 60 Rc. I prefer A2, A2 is very similar to O1 but is air hardening and you can grind to nearly a finish bevel prior to heat treat. O1 you need to leave a little thick for decarb. A2 has a small amount of chrome so it has a bit of corrosion protection, will not rust much but will stain. I stopped using O1 because everything rusted when setting on the bench for dew. But it is a great steel and will work well.
 
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