How high should I temper a 1084 chopper?

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Tenebr0s

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I am making a 10.5" chopper in 1084. I have hardened it in my kiln (10 min soak at 1500 F, quenched in Japanese voodoo industrial quench oil -- it is very fast stuff). After tempering for 1 hour at 400 F, my 62 rockwell test chisel wouldn't cut into it. Now, after 1 hour at 450 F, it barely cuts into it, and my 60 HRC chisel won't touch it, so I figure the blade is about 61 HRC. I've seen recommendations not to go much higher than a 450 F temper, but I'd appreciate any advice.
 
It's best to temper for2 hours for each temper.The best way to do this is to use a proper hardness machine and proper temperature measurement !
 
I have to tell you that I don't baby any the 1084 that we get today. The old 1500/400 recipe works fine for pretty much any application, although in my case, most of my Aldo and surplus Schrade 1084 ends ups in damascus with 15N20 so I automatically get a little but of extra toughness.
 
Profile and intended use matters. My own method is minimal temper, 400f for simple carbon @ 2 hours, twice, then for choppers I always draw the spine with mapp torch by oxidation colors while edge is immersed in water.
Normally thick spine with substantial distal taper, I like to turn stuff blue for spines and stress areas of anything that takes repeated shock.
 
I will defer to the experts on this, but I do wonder how hard the interior of a thick 1084 blade will get up by the spine? I know that our typical 1084 is not nearly as shallow harding as 1095 or W2, but it is still not a deep hardening steel by any stretch of the imagination. I wonder what the actual hardest of a 1/4 inch plus thick blade would be in the center of the spine when you temper the edge for say 60-61Rc? I am sure that the difference would not be anything like say a W2 blade where you get the "accidental hamon" but I wonder if there is still a difference?
Matt River said:
Profile and intended use matters. My own method is minimal temper, 400f for simple carbon @ 2 hours, twice, then for choppers I always draw the spine with mapp torch by oxidation colors while edge is immersed in water.
Normally thick spine with substantial distal taper, I like to turn stuff blue for spines and stress areas of anything that takes repeated shock.
Click to expand...
 
A caveat. I bought a big hunk of Aldo's original batch of 1084 which may have had a bit more vanadium than the current recipe, so my experience may be with what, IIRC, I might call "1086M Lite" What I do know is that the handful of monster blades that I made from that stuff get nasty sharp.
 
what are you chopping? my 1084 cleaver is tempered to Rc62-63, no toughness issues, although I don't chop bones with it. with 1/8" stock, a soak of 5 minutes at 800C should work. two 30 minute tempers with a cold water quench in between should be plenty.
scott
 
Thanks for the replies. I'm going to put a quick edge on it today and do some testing. It's not for chopping bones; just general camp chopper work, mostly tree limbs.


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I have been using Aldo's 1084 since the very first run he did. After a pre-HT thermal cycling regime, I do a 1475F quench. Heavy, high impact choppers get 425F temper cycles, thinner cutters get 400F.
 
Nothing. Which in my opinion, is the point of doing something.;)


Aldo's steel comes highly spheroidized, which is a pleasure to grind, drill and machine. My opinion is that you need to address those spheroids and redistribute that carbon. Is it the end of the World? No. A bit of a soak can do wonders... 1084 is a perfect eutectoid anyway so that is in your favor, too. I like to control every process and in-house thermal cycling is my way of "knowing" what I am working with.
 
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