Newbie steel question.

[Larrin]

Larrin,

Don't some blade smiths still make the tangs softer than the blade when they are forging to give them extra strength, toughness would be the better term I think?

I know some used to, not sure if they still do or not.

Something I was thinking about the other day, figured I would ask.


Jim

I don’t know about tangs specifically but differential heat treatments are relatively common to make the spine softer than the edge. They prefer the blade to stay bent rather than snap.

[Ankerson]

Larrin,

Don't some blade smiths still make the tangs softer than the blade when they are forging to give them extra strength, toughness would be the better term I think?

I know some used to, not sure if they still do or not.

Something I was thinking about the other day, figured I would ask.


Jim

I don’t know about tangs specifically but differential heat treatments are relatively common to make the spine softer than the edge. They prefer the blade to stay bent rather than snap.

Larrin,

Yeah. :)

Was something about when they use the smaller hidden tangs if I remember correctly, it's been awhile...

So they would bend rather than snap off.

Jim

[cistercian]

I am enjoying this thread. Larrin and Ankerson are epic. I would love to spend an evening
trying out different knives in different steels with you guys...I can't imagine a better time!
The conversation would be excellent!!!

I consider myself a steel snob but I really like S30V for EDC. It holds an edge well and sharpens
easily. I Prefer M390 or one of it's analogs however...It seems to hold an edge better. My M390 PM2
is a prized possession. I really wish it were easier to get my favorite knives in it.
I highly prize corrosion resistance and edge holding...and something not too horrible to sharpen.
I don't baton...I just cut stuff.
So S30V and M390 are fine for my needs. I have a decent axe and machete so ultra duty chopping
is covered. But they both are slathered in oil!!!

[Ankerson]

I am enjoying this thread. Larrin and Ankerson are epic. I would love to spend an evening
trying out different knives in different steels with you guys...I can't imagine a better time!
The conversation would be excellent!!!

I consider myself a steel snob but I really like S30V for EDC. It holds an edge well and sharpens
easily. I Prefer M390 or one of it's analogs however...It seems to hold an edge better. My M390 PM2
is a prized possession. I really wish it were easier to get my favorite knives in it.
I highly prize corrosion resistance and edge holding...and something not too horrible to sharpen.
I don't baton...I just cut stuff.
So S30V and M390 are fine for my needs. I have a decent axe and machete so ultra duty chopping
is covered. But they both are slathered in oil!!!

I am sure Larrin would be much more interesting to talk to than I would be. :)

He grew up in a knife making family so I am sure he could tell some great stories.

And he is a Metallurgist so that would add a lot to that conversation.

[Fright_Fox]

Hey everyone I was away for work and just checked back thanks for the new wealth of information I appreciate it.

[Pelagic]

Hey everyone I was away for work and just checked back thanks for the new wealth of information I appreciate it.

As to your specific question, if you look closely at the chart Larrin posted, it shows that 1095 yielded approximately 33% better toughness then s30v at equal hardness. Initially I didn't look closely enough at the chart, as I was flabbergasted by Larrin's comment making it seem like s30v and 1095 are equal in toughness. But the testing clearly dictates that there is a considerable difference, which with I fully agree.

[vivi]

Hey everyone I was away for work and just checked back thanks for the new wealth of information I appreciate it.

As to your specific question, if you look closely at the chart Larrin posted, it shows that 1095 yielded approximately 33% better toughness then s30v at equal hardness. Initially I didn't look closely enough at the chart, as I was flabbergasted by Larrin's comment making it seem like s30v and 1095 are equal in toughness. But the testing clearly dictates that there is a considerable difference, which with I fully agree.

Yep, those two steels clearly have different levels of toughness, even at the same rc.

[Larrin]

I clearly wrote that they are in "the same range." I don't know why I post charts if no one looks at them.

[Pelagic]

I clearly wrote that they are in "the same range." I don't know why I post charts if no one looks at them.

Do you honestly believe no one looks at them?

I did look at the chart, but upon closer inspection it was clear that it indicates 1095 is considerably tougher. There are a lot of data points in a very small space. Throughout all my posts I stated that there was something I'm not understanding. I found what it was. Big deal? Not to me!

[Larrin]

Do you honestly believe no one looks at them?

I did look at the chart, but upon closer inspection it was clear that it indicates 1095 is considerably tougher. There are a lot of data points in a very small space. Throughout all my posts I stated that there was something I'm not understanding. I found what it was. Big deal? Not to me!

I'm happy your faith has been restored in toughness testing. :)

[JuPaul]

So...kind of an off-topic (and maybe dumb-a**) question, but why are Rockwell hardness units sometimes abbreviated as "Rc" and sometimes as "HRC"? Are both correct? Any difference?

[Larrin]

So...kind of an off-topic (and maybe dumb-a**) question, but why are Rockwell hardness units sometimes abbreviated as "Rc" and sometimes as "HRC"? Are both correct? Any difference?

HRC is probably more correct. I use them both.

[JuPaul]

So...kind of an off-topic (and maybe dumb-a**) question, but why are Rockwell hardness units sometimes abbreviated as "Rc" and sometimes as "HRC"? Are both correct? Any difference?

HRC is probably more correct. I use them both.

Thanks. To be perfectly honest, I just didn't want to look like an idiot by using the wrong term. :p Glad to know both are acceptable.

[dlum1]

Thank you for the wealth of data and charts Larrin. I'm a huge fan of the unbiased data and have been following your blog for a few weeks by now. Perhaps the biggest point of confusion most people have is with respect to error propagation. Most people see data points and assume they're absolute values. You clearly state that nearby points are in the same range, but I'm not sure if that is getting the point across. I wonder if error bars might help? Or perhaps plot the points as ellipses / circles to include error so that people get a better understanding of overlapping possible values on your chart? For example, I was floored to learn that 1095 and s30v have similar toughness ratings... and it's making me reevaluate what I type of knife I take into the woods for backpacking. But to say that 1095 is 33% tougher than s30v may not be indicative of the statistical nature of measuring the material properties -- it only means that the 1095 data point is 33% larger than the s30v data point. Then again, perhaps you already have the error bars in the charts, but they're too small to see or be worthwhile plotting. Either way, it's just a suggestion and the charts are already quite impressive as is. Thanks for the hard work.

[Larrin]

Thank you for the wealth of data and charts Larrin. I'm a huge fan of the unbiased data and have been following your blog for a few weeks by now. Perhaps the biggest point of confusion most people have is with respect to error propagation. Most people see data points and assume they're absolute values. You clearly state that nearby points are in the same range, but I'm not sure if that is getting the point across. I wonder if error bars might help? Or perhaps plot the points as ellipses / circles to include error so that people get a better understanding of overlapping possible values on your chart? For example, I was floored to learn that 1095 and s30v have similar toughness ratings... and it's making me reevaluate what I type of knife I take into the woods for backpacking. But to say that 1095 is 33% tougher than s30v may not be indicative of the statistical nature of measuring the material properties -- it only means that the 1095 data point is 33% larger than the s30v data point. Then again, perhaps you already have the error bars in the charts, but they're too small to see or be worthwhile plotting. Either way, it's just a suggestion and the charts are already quite impressive as is. Thanks for the hard work.

Thank you for the suggestions. I cannot disagree that 1095 has higher values than S30V. Error bars are a good idea but would perhaps make the chart even busier and less intelligible than it is currently. The bigger question is perhaps how much difference in toughness is necessary to be significant and to that the answers are not as simple as I wish they were. My point was primarily that 1095 is not a "high toughness" steel in the same way that something like 5160 is, and I think you are right that the direct comparisons to S30V mostly muddied the discussion.

[Ankerson]

I clearly wrote that they are in "the same range." I don't know why I post charts if no one looks at them.

Yup, and they are by your chart in the same range.

Not all that much of a difference by the chart, not enough of a difference that one would really see it in real use anyway given two knives made the same way etc. By the chart taking the numbers for what they are it could go either way depending on the variables being they are that close.


Something like 1095 compared to 52100 or 5160, that's more of a real difference that people should really see in real use.

The problem I see with using charts is people will focus on the numbers and even if they are close as they are here comparing S30V and 1095 they will assume they are written in stone and that is huge difference. It's not a large difference at all in reality.

But then we know toughness numbers are subjective in the 1st place when it comes to knife blades.

So your statement about them being in the same range was correct as you already knew. :spyder:

[Ankerson]

Take a poll and ask the entire knife community which knives (folders only) have been the most chippy for you, s30v, or 1095?? I guarantee they will ask you what the point is of the question, and that OF COURSE S30V more prone to chipping. Most likely 100% of bladeforums (except for newcomers that have only looked at charts) will agree to this. How is a tough steel chippy? How can one say "it's more likely to fracture, but trust the chart, it's tougher"? This is what I dont understand.

I'll say just this: Pretty much all mass produced 1095 knives are hardened to 56-58HRC, folder or fixed blade, while S30V is usually in the 60-62 range. What does that mean? That for the user, in this case the average bladeforum guy, they'll see that their 1095 is 2-3 times as tough than S30V, and it is. But it's because of the hardness difference, not because of the material. Get 1095 to 60-62 and it will be just as edge chippy as S30V with identical hardness

I have some knives in a2 and 1095 at 61rc and they're very tough. Reprofiled them thin like all my other knives and they baton through wood etc.

I'm not convinced 1095 and s30v have equal toughness based on my experience with them.

Batoning puts more stress on the ricasso of the knife, that's the part between the sharpened edge and the handle/Tang than it does the actual edge. That's why when the knives break when batoning they normally break in that area.

Since the blade is thicker than the edge is you get a separation and the edge doesn't normally hit the wood normally after the splitting starts. The sides of the blade take MOST of the friction.

Figured I would add some clarification on the battening, about the wood separating and not hitting the edge. For those who try and use battening as proof of edge retention. I don't normally baton much so I had to wait until I had photos to post...

Photos....


Can clearly see the edge in not hitting any wood...

750_2614 by Jim Ankerson, on Flickr


Cropped in to show more detail

750_2614 baton by Jim Ankerson, on Flickr


The knife blade acts as a wedge as seen here.


750_2613 by Jim Ankerson, on Flickr