Sending off first batch of blades (Aldo's 1084).. What Rockwell Hardness?

Hawk45

Hawk45

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Jan 28, 2005
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Sending in my first 17 fixed blades of different thickness and length to Peterson's Heat Treat. I used 1084 for all of them. They need to know what Rockwell hardness I want them. Being my first time getting this done I want to make sure I request the right hardness. Does 65 RC - 66 RC sound about right?? Do I need different hardness for the different sizes based on type of use the blade will get (box opener vs chopper)?

I have:
- several small 1/8" thick necker type knives
- several mid-size blades in 1/8" - 1/4" thick
- a 14" bowie in 3/8" thick
- a 22" light machete/camp copper in 3/8" thick

What do you recommend?

I can't wait to get these out and see how they turn out. Looking back at them from the first to the last, I can really see my progress and what I really need to work on.

Thanks to you'all here. Such a great place.

John
 
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65 - 66 HRC is way too hard.

You would be lucky to get that hardness straight out of the quench.

I would suggest something around 58 - 60.

Large blades = 58 HRC, possibly a bit less for the machete.
Small blades = 60 HRC
 
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Not many steels are usable at that hardness. One of the only exceptions I know of is super tool steels, such as CPM REX 121, which can be used as a knife at 68-70RC.

For a chopper, I'd say 57-58. Most machetes are closer to 55-56, I think.

Higher RC = better edge retention in cutting tasks, but it gives you a more brittle blade that can chip/break when chopping. Another exception is spring steel, which can survive chopping at higher RC levels. But eve then, they're usually differentially heat treated - 59-60 on the edge, but only 45-50 on the spine so they can't just break.
 
Grease said:
Not many steels are usable at that hardness. One of the only exceptions I know of is super tool steels, such as CPM REX 121, which can be used as a knife at 68-70RC.

For a chopper, I'd say 57-58. Most machetes are closer to 55-56, I think.

Higher RC = better edge retention in cutting tasks, but it gives you a more brittle blade that can chip/break when chopping. Another exception is spring steel, which can survive chopping at higher RC levels. But eve then, they're usually differentially heat treated - 59-60 on the edge, but only 45-50 on the spine so they can't just break.
Click to expand...

Who sells CPM REX 121?
 
No need to go to 57 with Aldo 1084 for anything short of a truck srping IMO. I haven't taken any of my 1084 or W2 anywhere below 60 for 4 years and I through fully harden all of my blades up to the back end of the ricasso. Remember that at 3/8 inch, the core of your blade up by the spine may not get to the same hardness as the edge anyway. This is not as much of an issue with the 1084 as with the 1095 or W2, but we are still talking about a fairly shallow hardening steel compared to say O1 or 52100.
 
I agree with Stan, who agrees with James ,who agrees with Johnathan.

With 1084 .... 58-59 for rougher use 59-60 for finer cutting.
 
While I agree with Stacy, who agrees with... etc :D... I think I will run my next batch of low-allow steel (even the larger ones) at 60 and do some more testing. It's very easy to temper a whole blade back a bit more if you decide it's a little too hard, and not much harder to draw back just the spine and tang.
 
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