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

kdstrick

kdstrick

Joined
May 27, 2007
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Over the past nine years I've used and abused many knives. Some of my Busse's hold an edge FOREVER no matter what I do to them.... others seem like they don't retain the edge quite as well.

I have noticed my users seem to perform better than one with a factory edge. The more I sharpen them they better they seem to hold their edge. There's plenty of anecdotal evidence over the years of other folks having a similar experience. Or of a busse 'self-repairing' after use like a freakin terminator!!

Could the steel be 'better' the more you remove? I'm not sure how that makes sense but it seems to be the case.

Anyone else notice this? It could just be that I'm nuts.... ;)

Whatcha think?????

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This is pretty common with many knives, but it depends on heat treat and/or how the knife is sharpened.

If the knife is 80-90% ground when it goes to heat treat (or tempering) the thinner areas can get a little too hot. Sharpening away a little over time will expose the more hardened material.

Same applies if the person who sharpened it got the edge too hot, more commonly near the tip.

Final factor is that all carbon steel can "work harden" meaning basically the more you use it the harder it gets.

There are probably more potential issues like a bad heat treat over all but I don't think that would be a factor with Busse.


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kdstrick said:
Over the past nine years I've used and abused many knives. Some of my Busse's hold an edge FOREVER no matter what I do to them.... others seem like they don't retain the edge quite as well.

I have noticed my users seem to perform better than one with a factory edge. The more I sharpen them they better they seem to hold their edge. There's plenty of anecdotal evidence over the years of other folks having a similar experience. Or of a busse 'self-repairing' after use like a freakin terminator!!

Could the steel be 'better' the more you remove? I'm not sure how that makes sense but it seems to be the case.

Anyone else notice this? It could just be that I'm nuts.... ;)

Whatcha think?????

.
Click to expand...
Yeah, this is a phenomenon with many, if not most, production knives. The factory machine sharpening burns the edge. It can range from a few atoms at the apex to several millimeters of blade.

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Old Busse is the Best Busse!

There is a reason Jerry keeps telling people to Beat Them!!!
 
cpirtle said:
This is pretty common with many knives, but it depends on heat treat and/or how the knife is sharpened.

If the knife is 80-90% ground when it goes to heat treat (or tempering) the thinner areas can get a little too hot. Sharpening away a little over time will expose the more hardened material.

Same applies if the person who sharpened it got the edge too hot, more commonly near the tip.

Final factor is that all carbon steel can "work harden" meaning basically the more you use it the harder it gets.

There are probably more potential issues like a bad heat treat over all but I don't think that would be a factor with Busse.


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Click to expand...

Very enlightening. This is what I had suspected... seems is maybe the thin area close to the edge needs to be worn away a bit for the blade to reach it's potential.

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I'm not sure I agree. I think your sharpening is just better than the factory edge. I don't think the belt is going to change the properties of the steel.

There are also some models that have been heat treated harder.
 
TripleT said:
I'm not sure I agree. I think your sharpening is just better than the factory edge. I don't think the belt is going to change the properties of the steel.

There are also some models that have been heat treated harder.
Click to expand...

That's definitely a factor. Replacing a V edge with a convex edge on a chopper certainly improves performance in my experience.
 
TripleT said:
I'm not sure I agree. I think your sharpening is just better than the factory edge. I don't think the belt is going to change the properties of the steel.

There are also some models that have been heat treated harder.
Click to expand...
A better edge angle is definitely a factor, but there's no doubt that edges can and do burn with belt sharpening.

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Pretty common theme across manufacturers. From folders to fixed blades. A few sharpenings gets you into fresh steel.
 
Sharpening a knife on a stone, crock sticks or edge pro will never damage the heat treat. Knife makers use belts or other proprietary machinery to put the edge on even if they finalize with a manual step. Too fast or too hard and you can burn out the heat treat lightning fast on a knife edge thinner than a hair. I've sharpened hundreds of knives on a 2x72 KMG and it just takes the right touch and plenty of practice. AFAIK the only way to get a convex edge in a production environment is on a slack belt which is a little slower and leaves a little more room for error.

WRT sharpness, a V grind will always be sharper cutting because of edge geometry, there is not the hump of a convex grind to overcome. It also has a more acute edge than convex. The trade off is edge strength, on the same knife convex is a stronger edge because of the fact that there's more material behind the edge to support it. For a chopper I will take convex any day, V grind for utility because it's more versatile but you'll be sharpening it a little more.


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More sharpen = get those over heated factory sharpened edge off. You also get thicker geometry and semi convex edge of you do it by hand.
 
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I have burned edges on my belt sander. In simple carbon steels like 1095, 1065, 1055, and I did a number on a 5160 knife right at the tip. Once I sharpened past that, it was fine.



Some of the older Busse knives in info were run harder.


I've had two BADS, and the one I used, you could tell the difference in edge retention.

The knives are also run at a target hardness. There is a window, so you may have one that would test at the bottom of that window, and one that would test at the very top. Both are within specs, but the performance difference in edge retention should be dectectable.
 
Robdude said:
An argument came up early this week as to whether infi formula had been changed over time.. Jerry cleared up the issue at the end...see link
http://www.bladeforums.com/forums/showthread.php/1387086-INFI-amp-SR101-Weight-Comparison
But as for fresh sharpening holding a better edge... hell yes...totally true.
Click to expand...

Read closer.... he did not say whether it had been changed over time. He said "We have never made a change in steel analysis because of cost. NEVER!"

So in my mind, he is saying that the cost of steel does not factor into the INFI formula.

I believe he is saying that performance is everything. In reading through it all it seems that JB is a man constantly improving his art.


Still, back to the OP.... some of mine are better than others.
 
I really liked what Jerry said made sense to me if I didn't think the newer knives where as good as the old ones I wouldn't buy then
 
No all infi is equal.
I bought a NMFBM that broke it's tip on a dresser, didn't drop it etc, it barely hit the wood and broke the tip.

My other nmfbm will go through coins like paper.
 
HwangJino said:
No all infi is equal.
I bought a NMFBM that broke it's tip on a dresser, didn't drop it etc, it barely hit the wood and broke the tip.

My other nmfbm will go through coins like paper.
Click to expand...


That sucks. So you sent that one back for replacement, right?
 
cpirtle said:
Sharpening a knife on a stone, crock sticks or edge pro will never damage the heat treat. Knife makers use belts or other proprietary machinery to put the edge on even if they finalize with a manual step. Too fast or too hard and you can burn out the heat treat lightning fast on a knife edge thinner than a hair. I've sharpened hundreds of knives on a 2x72 KMG and it just takes the right touch and plenty of practice. AFAIK the only way to get a convex edge in a production environment is on a slack belt which is a little slower and leaves a little more room for error.

WRT sharpness, a V grind will always be sharper cutting because of edge geometry, there is not the hump of a convex grind to overcome. It also has a more acute edge than convex. The trade off is edge strength, on the same knife convex is a stronger edge because of the fact that there's more material behind the edge to support it. For a chopper I will take convex any day, V grind for utility because it's more versatile but you'll be sharpening it a little more.


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Click to expand...

Listen to the knife maker. Experience tells.
 
Equal? Not sure what it is that is supposed to mean. I have owned INFI since the beginning. I still buy it, if that tells you anything. I know that Busse favors toughness over anything else. I have tested severely modern INFI and it is still ranking higher than anything else in toughness. Edge holding, well here is my personal opinion. I wish Busse would offer INFI at 61 Rc. The original run INFI was Rc over 60. Typically 60-61. I know INFI can still be tougher than 99% of the steels made today at 61. But Busse knows how crazy people are about abusing his knives so he probably dropped it for that reason. Who knows. Make no mistake when you hear people say, the modern INFI does not hold an edge well, it is likely because of the grind design more than the steel.

I did this for a total of about 7 minutes to this knife. If you count hammer strikes(I am very good and accurate with a hammer), I easily did 350+ hammer strikes. These were not light strikes. They were hard strikes. Those are 3/8" thick cement nails. Tough as hell. Many times tougher than the typical nails you see in demos. Also my hammer strikes were hard, I have seen others cutting nails with a light tapping, instead of hard hits. The knife noted had a 15dps edge. It indented so little that Busse reground it and sent it back to me.

[video=youtube;zzpL9CW_AJA]https://www.youtube.com/watch?v=zzpL9CW_AJA[/video]


I have yet to see a steel that can do better than this. And yes I have tested some 10+ steels this same way. Most of them broke through.
 
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