Steel choice / A2 vs O1 or Other

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Hello All - After a long hiatus I would like to make some more leather tools. I’ve recently been using blades made from Aogami Blue and they put the blades that I’ve made from O1 to shame. They are much harder and holds an keen edge.

I’m considering A2 for the next round of knives. By the book, it looks like a fairly easy steel to air harden but would like to get some real world input. Additionally, what other steels should I be considering to maximize hardness.

I’ve recently purchased a small used muffle furnace that can sustain 2012f. I’m excited to use it during the hardening process.

Thanks as always
 
Based on what you've said, I assume you intend to do the heat treating yourself....with the "muffle furnace"..... with A2, if you want optimum heat treat, I doubt you'll achieve it with the "muffle furnace"... UNLESS it offers a programmable controller. A down and dirty heat treat for A2 is:

Preheat slowly to 1350-1450F and hold at this temperature until part is uniformly heated. After thorough preheating, heat to 1750-1800F. Hold the work piece at the hardening temperature until it is completely and uniformly heated. A2 is an air hardening steel and will develop full hardness on cooling in still air.

If the furnace can accurately accomplish the "hold/soak" then you're in business. Considering that the cross sections are going to be very thin for leather working tools, I would recommend "plate quenching".

It's very likely that the key to the tools from the Aogami Blue, and the reason they hold up better was/is the heat treat.

In many cases, folks will use specific steel types simply because of either familiarity, or because they have the means to heat treat them properly.

There are a number of various steel types that will make great leather working tools, but you have to consider whether you have the means (tools/tooling) to work/heat treat the steels.
 
Thanks Ed - The furnace is programmable so I think I’m good.

So from what I read,
First wrap with stainless foil (necessary?),
After preheat and soaking at critical (1750-1800), quickly lay the blade down between two pieces of aluminum and clamp together. Cool to 150f.
Then immediately temper at 300f to get 62.

For a small blade, how long should I soak for?

What is your opinion on W2 steel?

Thanks again!
 
Personally, I would foil any steel prior to using an oven for heat treat. The generally listed soak time for A2 is 30 mins per inch of thickness. There are so many variables that come into play with soak times, I suspect it's going to require some experimentation on your part.

Any time I heat treat a steel for the first couple of times, it's a "trial run", to tweak the specifics. For example, when I first started using CPM154, which calls for a 30-60 min soak, I found that 30min wasn't long enough, and 60min was too long (various reasons).

I sacrificed about 6 blades before I nailed down the time that works best for my situation. What you must understand about heat treating data is..... it's designed by industry, for industry...... meaning that it's very general in nature. To get the best out of any heat treat in a knifemaking application, it often requires each individual to do some experimenting, and usually sacrifice a few blades, in order to get it "nailed down".

You also asked about W2. IMO, there are far better choices for performance in a blade. Personally, I only use W2 for very specific situations, and not very often.
 
Ahhh. Yes. I should have figured that out by now. Nothing beats trial and error and tedious note taking. I work in a lab so I should have understood that.

Thanks for your opinion on W2. I will keep that in mind and stick to the A2 for now.
 
for do-it-yourself, you can't beat O1. for a basic blade 1/16" at spine, put in a furnace pre-heated to 1475F, once furnace says 1475F again, soak for 7-8 minutes, quench in 120F canola. wash in cold water. two one hour tempers at 325F should be Rc63-64. besides being less than half the price of A2, O1 does not need sub-zero or cryo for maximum hardness. i have had good results using 1/32" O1 which one customer used for skiving.
 
webicons said:
I’ve recently been using blades made from Aogami Blue and they put the blades that I’ve made from O1 to shame. They are much harder and holds an keen edge.
Click to expand...
Is it possible that you haven't dialed in your HT on O-1? I'm using both O-1 and A2...the O-1 is easier to HT and I think it sharpens easier than the A2. The A2 is much better on patina...stays polished longer. I can't imagine needing anything harder than the O-1 will get. I do think the A2 holds an edge longer, but the O-1 holds an edge as good (maybe better)as any factory kitchen knife I have. I actually like the O-1 patina but since I want to sell knives in a stainless generation I'm not going to push O-1. As a kitchen knife that should be cleaned after each use it's pretty hard to beat...

Try Scott's recipe, that's the one I use. I get great results. I think I first tried that over two years ago and have not bothered to use any other recipe. I'm still testing A-2 recipes...trying to find a good one that doesn't take all day...lol.

I have a paragon oven which helps with the more complicated HT A2 requires. I made the jump to A2 because I have always loved it as a tool maker by trade...SUPER stable and very tough. Both O-1 and A2 are great steels...both perhaps way underrated.
 
O1 is the only steel that I’ve been using until now and I was hoping to increase my knowledge base.

I do see that A2 can benefit from a cryogenic treatment but it doesn’t seem a requirement.

Damn. I wish I had a hardness tester...
 
Thanks Ted - Yes, it is quite possible that my process for O1 isn’t optimized as I just purchased the programmable oven.

I will revert back to the O1 as recommmended and see the difference it makes.

Thanks all.
 
I don't have a HT oven and have had very good results with O1. One brick forge, go to critical temp, quench in 130 to 140 canola temper 2 hrs at 400. This has netted me 61 Rockwell Hardness on my tester. With an oven I'm sure you can get better results.
 
I’ve always heated up my Canola oil before the quench but can anyone tell me the reasoning behind it? In my mind, heating up the oil would slow down the quench. Is this the reason why?

Is it done to minimize the chance of warp or cracking the blade and do I really need to be concerned about this with stock removal?

It’s just something I’ve done without understanding the principle behind it. Thanks!
 
I don't know the terminology but with the extreme hot blade and cold oil, a barrier of steam forms around the blade as you quench. So the quench indeed does take longer and if I understood the gent that told me the, quench is not as good and is inconsistent due to some parts of the blade cooling quicker than others.
 
Gliden07 said:
I don't know the terminology but with the extreme hot blade and cold oil, a barrier of steam forms around the blade as you quench. So the quench indeed does take longer and if I understood the gent that told me the, quench is not as good and is inconsistent due to some parts of the blade cooling quicker than others.
Click to expand...
I notice most of you "oil guys" move the blade slowly in the quench...is this to keep that barrier from forming?
 
certain oils, canola and some commercial quench oil, work better when heated to 115F to 130F. some oils form a vapor layer,some don't, canola does not. you move the knife in the oil to keep it in cooler oil and you always go up and down or you cut; Never side to side(supposed to warp the blade)
here is a study of canola and other veg oil against commercial oils https://www.researchgate.net/public...ling_Properties_of_a_Series_of_Vegetable_Oils it explains in the study about heating the oil
 
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