Where to start with A2

S

Storm W

Joined
Feb 19, 2019
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915
Does someone have a handle on A2? I either got it wrong the last time I asked or something else happened. I made some test blades with it and they weren't horrible but they suck a bit as well. They are hard to put a edge on and get a wire edge that won't come off and seems to come back. I'm getting mine precision ground from Pops. Is there a prequench I'm missing . I gotta check notes on the recipe that I used but it was foil wrapped and plate quenched followed by LN. I have a fair bit if it and a bunch of people that want bushcraft knives. It sounded like the perfect steel. NJSB is out of the .130 15n20 that was my old standard.
 
DevinT said:
What temp are you quenching from? What hardness are you getting?

Hoss
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The recipe I used was 1750 for 20 mins and plate quench. Followed by LN and a 2x 400 temper. That's assuming I didn't screw something up it was shortly after getting my oven. I don't have a hardness tester so I'm not sure on the hardness but a wire edge that won't go away isn't a good sign. I so far they have just been turned into test knives but I wanted to ask around before a tried a new batch.
 
A2 can get HARD …. and TOUGH. The fact that the wire is resistant implies you got it hard and the wire is resisting breaking away because the edge is too thick..

First, make sure they are all the way sharp. Did you grind the bevel all the way down to an edge before sharpening? Is the edge too thick?
Take it to at least 400 grit if using a belt grinder to sharpen, or to a fine stone if doing it by hand.
Make sure the angle is right for the blade.

Then work off the wire edge by stropping on leather with green chrome.

BTW, your recipe should give you a blade around Rc 63.
 
Stacy E. Apelt - Bladesmith said:
A2 can get HARD …. and TOUGH. The fact that the wire is resistant implies you got it hard and the wire is resisting breaking away because the edge is too thick..

First, make sure they are all the way sharp. Did you grind the bevel all the way down to an edge before sharpening? Is the edge too thick?
Take it to at least 400 grit if using a belt grinder to sharpen, or to a fine stone if doing it by hand.
Make sure the angle is right for the blade.

Then work off the wire edge by stropping on leather with green chrome.

BTW, your recipe should give you a blade around Rc 63.
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Thanks. I probably did something wrong then. I will have to get it checked then. The wire edge feels just like when I was trying to harden the super heavy sphereodized 80crv2 from Aldo without normalizing. It does hold a edge better than that but the wire edge keeps coming back. I will run a test coupon and see if I can get it Rc tested.

Will it hold up around 63Rc for bushcraft work? Its going to family members who will give me feedback but i don't want them stuck with a broken knife.
 
If they're going to baton it through wood, I'd dial it back to ~61Rc.
What angle are you using to sharpen? By hand or belt?
In my experience, A2 doesn't really want to be below 15dps. It will roll a bit. I had a customer who obsessively stropped his knives at low angles. Didn't do great with a piece of my A2, but I simply re-sharpened it on a stone at an appropriate angle, and *bingo*.
 
daizee said:
If they're going to baton it through wood, I'd dial it back to ~61Rc.
What angle are you using to sharpen? By hand or belt?
In my experience, A2 doesn't really want to be below 15dps. It will roll a bit. I had a customer who obsessively stropped his knives at low angles. Didn't do great with a piece of my A2, but I simply re-sharpened it on a stone at an appropriate angle, and *bingo*.
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I usually go with a fresh 220 followed by a course DMT and nock the burr off with a spyderco black and strip. I freehand somewhere between 15 to 20 degrees usually.
 
I'm with daizee, try a steeper edge angle. I bet the edge is rolling.

Of course this all is dependant on your HT working right. A-2 isn't a hard steel to HT with an oven, so I suspect the hardness is there from your parameters.
One other thing is how much post-HT grinding you do and if you make sure the edge doesn't get hot in grinding and belt sharpening.

Is your grinder VS?
 
Stacy E. Apelt - Bladesmith said:
I'm with daizee, try a steeper edge angle. I bet the edge is rolling.

Of course this all is dependant on your HT working right. A-2 isn't a hard steel to HT with an oven, so I suspect the hardness is there from your parameters.
One other thing is how much post-HT grinding you do and if you make sure the edge doesn't get hot in grinding and belt sharpening.

Is your grinder VS?
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Yes its variable speed. It sounds like I just need to run the test pieces again. I was doing them after work and maybe I ran them on a different program. They are just little test knives anyway. My AEB-L, S35VN and M2 all came out fine so o don't think it's the grinding. I will give them a but more angle and make a second just to be safe. Thanks. Would you change anything for making a bushcraft knife? I'm going to try to run them tonight I think.
 
Ive had a miserable time with starting A2.. I'm getting nothing but serious blade length (9"ish) warps.. Ive tried stress relieving and still the same warps happen. Ive tried plate quenching, still air quench, no bevel quench and all warped the same and baaad.. Ive pretty much wasted 6 feet of A2 and have 1 bar left.. all from same supplier. Stock removal as well, I'm lost
 
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