All INFI is created equal... or is it???

me2 said:
As far as I know, he only sharpens with diamond, so no other stones were tested. As for temperature, he sharpened on the same stones dry then wet. I haven't discussed it in detail, so he may have done more than just that. He's a member here, though not terribly active.
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I do believe the wet sanding is better much in the same way it works well when doing auto body work. And I can believe you get better results. I just don't think those results have anything to do with heat. Not by hand anyway.
 
I have several friends who are full time knifemakers who sharpen their blade with belt grinder and remove the burr off with electric buffer.

6 years passed since I know them, drink with them almost every week and I have yet to hear any complain about the lack of performance due to weakened edge...
They are use the steel that tempered below 400F like 52100, 5160 and I'm talk about working knife.

I even feel that the way they sharpen will get much more aggressive edge than hand sharpening one.
 
All I know about this is that my SHBM has, and has retained, the best edge of any knife I've ever owned. Maybe it's the steel, or maybe it's the asymmetrical edge, or maybe I just got lucky on that knife, but it's damn near perfect.
 
TripleT said:
hehehehe, unless you do it wrong :)

But then the damage wouldn't be from heat anyway.

Just don't ask me to reprofile S90V ever again...
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Well that's definitely the truth!


I don't have any INFI currently, but SR101 certainly holds an edge amazingly. I've used my Regulator for some rough stuff.

Sent from my SM-G920V using Tapatalk
 
JohnTheTexican said:
All I know about this is that my SHBM has, and has retained, the best edge of any knife I've ever owned. Maybe it's the steel, or maybe it's the asymmetrical edge, or maybe I just got lucky on that knife, but it's damn near perfect.
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You didn't get lucky. MY SHBM's have held an edge much longer than many high carbon stainless steel knives I have owned.
 
Cobalt said:
I do believe the wet sanding is better much in the same way it works well when doing auto body work. And I can believe you get better results. I just don't think those results have anything to do with heat. Not by hand anyway.
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Here in lies the issue. We have 2 different experiments that provide different results. The question is why? At this point, I don't think we have enough information to get an answer. Unless there is some reason to think the one Roman referenced was faulty or made up, there is no reason to dismiss it.

I sharpened blades by belt sander for years with no apparent issues. That doesn't mean they weren't there, but that I just didn't notice them, or did not attribute them to the proper cause.
 
me2 said:
Here in lies the issue. We have 2 different experiments that provide different results. The question is why? At this point, I don't think we have enough information to get an answer. Unless there is some reason to think the one Roman referenced was faulty or made up, there is no reason to dismiss it.

I sharpened blades by belt sander for years with no apparent issues. That doesn't mean they weren't there, but that I just didn't notice them, or did not attribute them to the proper cause.
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True. Also, trying to measure the temperature on a micrometer size point at the apex of an edge is something that I would think is near impossible with anything but a highly sensitive thermal camera. Especially when you consider that the smallest thermocouple is an order of 10 larger than the micrometer measurement claimed by Landes. Frankly, I have a hard time believing that report. I know Landes is a known entity and well respected in his field. However, I would love to see the explanation of how he measured a much smaller point then the measuring device and then proceeded to measure a section that supposedly was 500 degrees Celsius hotter than the melting point of steel. I have also pulled up a few reports one of which I added to this thread that are more closely aligned to what the op in the other thread claimed than what Landes claims.

Sometimes, individuals who are well respected in an industry make claims thinking that they do not have to explain their claim. I have seen that on BF in the past year. "Just because you say it doesn't make it true".
 
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I hope jerry keeps on developping INFI
It would be great if he developped a custom steel again like ols INFI with nitrogen rather than the new INFI (A8mod)
 
Cobalt said:
True. Also, trying to measure the temperature on a micrometer size point at the apex of an edge is something that I would think is near impossible with anything but a highly sensitive thermal camera. Especially when you consider that the smallest thermocouple is an order of 10 larger than the micrometer measurement claimed by Landes. Frankly, I have a hard time believing that report. I know Landes is a known entity and well respected in his field. However, I would love to see the explanation of how he measured a much smaller point then the measuring device and then proceeded to measure a section that supposedly was 500 degrees Celsius hotter than the melting point of steel. I have also pulled up a few reports one of which I added to this thread that are more closely aligned to what the op in the other thread claimed than what Landes claims.

Sometimes, individuals who are well respected in an industry make claims thinking that they do not have to explain their claim. I have seen that on BF in the past year. "Just because you say it doesn't make it true".
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I don't think Landes did the experiment, but found it while doing research for his book. It was from some work done in the German razor industry. The temperatures are above the melting point of steel by a fair margin. There is however a time element, and the times at those temperatures were very short, much less than a second, and very shallow on a 2" cube. In the grand scheme of things, the range of speed for hand held sharpening is pretty small, from very slow (inches per minute) as might be used on finishing passes, to 2-3 feet per second. At my fastest, while maintaining control, I can manage 3 passes on a 6" stone in about a second. While that isn't enough to show sparks, I don't have any issue believing that it could heat up the edge very quickly, and it would just as quickly cool back down. The real question is, if those temperatures are reached, but for very short times, how do they effect things. That question I have not seen addressed. Even the study you showed had temperatures reaching low austenization levels for plain carbon steels at very shallow depths. Is every knife like that ground on an uncooled grinder covered in a thin layer that has been rehardened and not tempered? I doubt it. At this point all I can say is we need more information, but I will take some precautions where feasible.
 
me2 said:
I don't think Landes did the experiment, but found it while doing research for his book. It was from some work done in the German razor industry. The temperatures are above the melting point of steel by a fair margin. There is however a time element, and the times at those temperatures were very short, much less than a second, and very shallow on a 2" cube. In the grand scheme of things, the range of speed for hand held sharpening is pretty small, from very slow (inches per minute) as might be used on finishing passes, to 2-3 feet per second. At my fastest, while maintaining control, I can manage 3 passes on a 6" stone in about a second. While that isn't enough to show sparks, I don't have any issue believing that it could heat up the edge very quickly, and it would just as quickly cool back down. The real question is, if those temperatures are reached, but for very short times, how do they effect things. That question I have not seen addressed. Even the study you showed had temperatures reaching low austenization levels for plain carbon steels at very shallow depths. Is every knife like that ground on an uncooled grinder covered in a thin layer that has been rehardened and not tempered? I doubt it. At this point all I can say is we need more information, but I will take some precautions where feasible.
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Makes sense. Very good points. And I agree.
 
I will say this... the custom shop Ash1 I bought with a beautifull convex edge has held up amazing out of box.. but everything else has held up much better after a good sharpening..
 
If you're able to, could you post a picture of the tip, showing the damage? Just for my, and I'm sure others, curiosity.

Can only see a beautiful NMFBM from this pic.

Either way, Jerry clearly has you covered.

But really, that's a damn nice looking NMFBM.


HwangJino said:
My life schedule is absolutely terrible, i barely have time for anything anymore.
it'd be easier selling the nmfbm to someone who wants one, since I have more than enough knives haha.
guess when I have time I'll pay for membership again and sell this pup.


Never even smelled wood once. :(
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xxwarderxx said:
If you're able to, could you post a picture of the tip, showing the damage? Just for my, and I'm sure others, curiosity.

Can only see a beautiful NMFBM from this pic.

Either way, Jerry clearly has you covered.

But really, that's a damn nice looking NMFBM.
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I have tried before, my phone camera (only camera I own) will not focus on the tip.
if there are tips (no pun intended) to taking picture of the tip I'd gladly give it a try.

this was a knife I planned on keeping a safe queen, so a broken tip sort of defeats the purpose.
 
me2 said:
I don't think Landes did the experiment, but found it while doing research for his book. It was from some work done in the German razor industry. The temperatures are above the melting point of steel by a fair margin. There is however a time element, and the times at those temperatures were very short, much less than a second, and very shallow on a 2" cube. In the grand scheme of things, the range of speed for hand held sharpening is pretty small, from very slow (inches per minute) as might be used on finishing passes, to 2-3 feet per second. At my fastest, while maintaining control, I can manage 3 passes on a 6" stone in about a second. While that isn't enough to show sparks, I don't have any issue believing that it could heat up the edge very quickly, and it would just as quickly cool back down. The real question is, if those temperatures are reached, but for very short times, how do they effect things. That question I have not seen addressed. Even the study you showed had temperatures reaching low austenization levels for plain carbon steels at very shallow depths. Is every knife like that ground on an uncooled grinder covered in a thin layer that has been rehardened and not tempered? I doubt it. At this point all I can say is we need more information, but I will take some precautions where feasible.
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I sense the core of an interesting dissertation topic for a metallurgist.

That said, rapid temperature changes like this are often only surface effects. It takes time for changes to occur in a crystal lattice in the bulk of a material. How much time? Depends on many factors, but certainly more than seconds.
 
Cobalt said:
True. Also, trying to measure the temperature on a micrometer size point at the apex of an edge is something that I would think is near impossible with anything but a highly sensitive thermal camera. Especially when you consider that the smallest thermocouple is an order of 10 larger than the micrometer measurement claimed by Landes. Frankly, I have a hard time believing that report. I know Landes is a known entity and well respected in his field. However, I would love to see the explanation of how he measured a much smaller point then the measuring device and then proceeded to measure a section that supposedly was 500 degrees Celsius hotter than the melting point of steel. I have also pulled up a few reports one of which I added to this thread that are more closely aligned to what the op in the other thread claimed than what Landes claims.

Sometimes, individuals who are well respected in an industry make claims thinking that they do not have to explain their claim. I have seen that on BF in the past year. "Just because you say it doesn't make it true".
Click to expand...

Agreed. Very hard to measure the temperature in a small area ... Of a solid sample.

In fact, as the area of concern shrinks, it's tough to understand what is even meant by the temperature. Classically, temperature is often defined for individual particles in a gas or plasma, where interactions between particles are better understood and more easily modeled.
 
OldPhysics said:
Agreed. Very hard to measure the temperature in a small area ... Of a solid sample.

In fact, as the area of concern shrinks, it's tough to understand what is even meant by the temperature. Classically, temperature is often defined for individual particles in a gas or plasma, where interactions between particles are better understood and more easily modeled.
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Mr. Egg head, where were you yesterday?;)

I guess it was not Landes who did the test. But the data posted from that test by Landes did not fully explain the results or the means. Kind of a worthless test if you ask me. To many variables.
 
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