Why lower RC on fixed blades with CPM 3V?

S

Sid Post

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Oct 14, 1998
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I am curious why some knifemakers heat treat smaller EDC size fixed blades to 58RC versus others that heat treat to 62~64RC.

Does a 58RC 3V knife really have an advantage for average EDC use cases in a 3"~5" fixed blade? Would the same blade at 62RC be more brittle and suffer edge chipping while doing reasonable knife tasks?

The reason I ask is that I see production knives commonly listed at 62~64RC and knifemaker options at 58RC frequently.

TIA,
Sid
 
The recommend 3v heat treat listed on the data sheet uses the higher temperature temper protocol and results in 58-59 Rc. Makers reaching higher hardness are using low temperature temper and cryo which is not as common as it should be.
 
The data sheet does show 2050°F/~1015°F results in about 61.5HRC. But it also has a statement on it that recommends 3V to be used at 58-60, so I would imagine it's the recommendation that people were looking at, and just looked at the temper chart to see how to achieve that hardness. They also recommend 1950°F/1000°F which results in 59HRC while stating this gives the best wear resistance/toughness combo. Again, I think most people decided to just take that advice and go with it.

But no doubt, the lower temper protocol gives much better apex stability while also being able to get quite a bit higher than 61.5HRC. I always temper pretty low after cryo and get 63HRC.

Great steel. Excellent combo of toughness and wear resistance, and while not stainless, does quite well in that department as well, compared to other tool steels.
 
There is always a chance the user drops it on the concrete floor. In that case I would want the softer blade. 64 HRC dropped on the concrete could end badly.
 
I have only ever made one knife out of 3V. It was a horrible experience. Like grinding glass. I threw the knife away. I'd guess knifemakers leave it softer so they can grind it. Production companies don't care because double disk grinders don't get frustrated with bevel grinding.
 
I like my knives to cut, and the edges to last, so most knives I make are 63HRC+. Dropping them on concrete really isn't a concern for me at all.

I don't ever have issues grinding high carbide, high hardness steels. The issue for me is when it comes to the hand rubbed finish. If you think 63HRC 3V sucks, try 65HRC 10V!
 
BeckTools said:
There is always a chance the user drops it on the concrete floor. In that case I would want the softer blade. 64 HRC dropped on the concrete could end badly.
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Maybe not especially with 3V. I had a blade in 3V fall 2 feet onto the concrete floor after glue up while the clamps were still on. Landed tip first with only the primary grind done at under 5 DPS. Given there was no edge but the bevels are brought to just under .01 before the final bevel. I cursed up a storm but everything was fine. My target for 3V is 63 HRC.
 
Fiddleback said:
I have only ever made one knife out of 3V. It was a horrible experience. Like grinding glass. I threw the knife away. I'd guess knifemakers leave it softer so they can grind it. Production companies don't care because double disk grinders don't get frustrated with bevel grinding.
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It is not the hardness of the steel that is giving you grief but the vanadium carbides. With a fresh ceramic belt 3V is not bad.
 
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