Which RC for O1

[pemihan]

Hi,

I have several blades made of B?hler K460 which is the same as O1.
Which RC would you aim for? 56/57 or 58/59?
It's working knives with blade sizes between 6 and 8" inches plus the full tang.
I want them to be tough but also hold a good edge..

Thanks
Peter

[Ed Caffrey]

There's one big factor that you didn't mention.....blade grind/geometry. The best way I can explain it, is to point you to an article that is on my website.... "The Overall Package"

Creating a great knife is much more than making something that looks like a knife, then focusing on a specific detail....in reality, the whole process is about details and nuances.

In this case, it seems that these might be the first couple of blades you've produced with this steel? If so, I would heat treat one to the lower level, and the other to the upper level, then seem how each performs. Any time I produce anything with a "new" steel, the first 2-3 are considered "sacrificial" to ensure I have the details/nuances down the way I want them.

[pemihan]

Thanks Ed, great read...

[Kevin R. Cashen]

Will the primary function be fine slicing or cleaving/chopping? O-1 has a hardness vs. toughness peak that is higher in Rockwell than other steels which is one of the reasons it is not at the top of the heap for large tough blades. I firmly believe that if you take it below 58 Rc you will lose out on both. Most of my tests show some form of plastic deformation on most edge damage with a steel like this, meaning it is not as dangerous as you may think to err on the hard side. For a fine slicing blade that will need to hold an edge I would keep it above 61 HRC, but if the application called for less than 58.5 to 59 HRC I would probably just switch to a different steel rather than sacrifice so much of this steel's potential.

[pemihan]

Originally Posted by Kevin R. Cashen

Will the primary function be fine slicing or cleaving/chopping? O-1 has a hardness vs. toughness peak that is higher in Rockwell than other steels which is one of the reasons it is not at the top of the heap for large tough blades. I firmly believe that if you take it below 58 Rc you will lose out on both. Most of my tests show some form of plastic deformation on most edge damage with a steel like this, meaning it is not as dangerous as you may think to err on the hard side. For a fine slicing blade that will need to hold an edge I would keep it above 61 HRC, but if the application called for less than 58.5 to 59 HRC I would probably just switch to a different steel rather than sacrifice so much of this steel's potential.

It's camp knives, so they will see all kinds of use, including splitting firewood and such...

Peter

[dbalfa]

I've use a lot of 0-1 and will give observational backing to Kevin's technical expertise. I treat all my 0-1 to above 60 - shoot for 62 based on HT technical sheet data. I made a nice large chopper/bush knife with it once, flat ground it to a fine edge, HT it to 60ish. It would cut like a razor and held edge well. I used it to chop some limbs etc, worked good. I took it Elk hunting and used it to hack open at a leg joint and ended up toting some of the shrapnel from the blade pieces home in my hide. Two things worked against me I believe- geometry (as Ed mentioned) and steel properties/HT (as Kevin mentioned). I could'nt change the HT so I re-ground the blade, backed the edge up about 1/2" which thickened it to a more obtuse angle. I then tested it extensively and got no chipping. Perhaps backing up the edge and moving it into a thicker portion of steel got it into a different HT zone within the blade, perhaps just the change in edge geometry made a difference, perhaps a combination of both. Either way, I agree with Kevin - practically speaking, 0-1 is much better suited for smaller slicing, skinning, using knives. I think I would stick with a medium level HC simple steel for a big chopper- 1084 maybe, 5160 perhaps?