Pushing INFI to its limits and beyond

C

Cliff Stamp

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Oct 5, 1998
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As of late I have been doing some chopping with a BM-E (early one bought when they first came out), and my SHBM. Now my BM isn't exactly standard, it is 0.275", no clip to the point, and weighs 660 g. I have also significantly changed the edge profile, so I wasn't looking at the raw performance as much as looking at how they handled, to check out the new grip mods mainly. More on that later.

I started off cutting some fresh wood, mainly pine, that went ok. Later on I switched to scrap lumber as I didn't have as much free time, and had to fit in chopping whenever I got a free half hour or so. This is when the surprises started setting in. I could not keep a working edge on my BM. The edge would constantly roll to a visible degree, you could see it bend or ripple. To be specific these were just barely visible by eye, the steel was 0.005" to 0.010" thick behind the bend.

Now the ripples were easily removed with a little pressure, no chipping as I would have expected. However I was not overly pleased by having to stop chopping every half dozen blocks (I was using mainly 4x4 and 6x6 posts), to fix the edge. Now I knew that the edge was much more acute than standard, but from memory, the last time I checked it, it wasn't that thin that I would expect the the damage to set in this frequently.

The last draw was when I went back to fresh wood and during bucking some spruce I whacked the knife into a knot in the worst possible way. It was kind of "movie-like" as I oculd sort of feel the chop happening in slow motion. I knew it was going to be bad and when it hit the knot I didn't have to check the edge to know it was going to be dented. Sure enough it was rippled to this time about 0.020" thick.

I straightened it with a nail set and a hammer and then adjusted the profile slightly by adding a convex taper to the last one mm or so of edge. I then checked the edge profile to see how much I had thickened it. It spec'ed out at ~11 degrees per side in the last bit of edge. This took me back because that is where I thought it was before I just altered it.

So I check the primary edge profile and it is ~8.5 degrees per side. Ok, now I understand why it was rippling so easy (relative of course, it only got damaged on knots with full heavy swings). This was a flat bevel, no convex taper, on a heavy blade balanced knife. Not bad at all. And of course, no chipping and all damage was easily repaired with the aid of a large hammer.

For those curious, I checked my notes on the ~8.5 degree mod, I did this to check just how much damage would be induce with wood working as I figured that INFI would set a solid benchmark. I was trying to figure out just how low you could go and still be functional. I seems that a sub mm micro-bevel would be enough for all but the worst impacts.

-Cliff
 
Interesting. I just reprofiled the edge on my Battle Rat yesterday. While I left the primary flat grind as is, I just extended the convex edge up the blade a ways and thinned the edge considerably. While I haven't measured the edge angle yet, I will tonite and would wager that it is approaching 20 degrees, included. The stock edge was approx 45-50 degrees. I will also tackle some seasoned hardwood to see if any damage occurs. I am expecting a major increase in performance and hope that I haven't exceeded the limits of the steel. Time will tell.
 
Originally posted by Cliff Stamp
(early one bought when they first came out)
Click to expand...

Could you post a pic? It is possible that it is a rare one.

Originally posted by Cliff Stamp
So I check the primary edge profile and it is ~8.5 degrees per side. Ok, now I understand why it was rippling so easy (relative of course, it only got damaged on knots with full heavy swings). This was a flat bevel, no convex taper, on a heavy blade balanced knife. Not bad at all. And of course, no chipping and all damage was easily repaired with the aid of a large hammer.

For those curious, I checked my notes on the ~8.5 degree mod, I did this to check just how much damage would be induce with wood working as I figured that INFI would set a solid benchmark. I was trying to figure out just how low you could go and still be functional. I seems that a sub mm micro-bevel would be enough for all but the worst impacts.

-Cliff
Click to expand...

I wondered why it was rippling so easily! That is an extremely thin edge for heavy chopping (heck, it's thin for most light-duty knives). How did it perform at 11* per side?

I have been thinning out the edges quite a bit on my knives recently, but am not sure of the best way to measure the angles of the edges. Any suggestions?

I am very interested to hear how the BM-E and SHBM compare, especially how you feel about the handles.
 
It is holding up fine so far, a dozen pieces of seasoned 2x4 and 4x4 yesterday with no problems, including a few knots, but no really bad hits. I will probably go up to 25 degrees included in the last little bit (mm or so), to allow it to handle the harder knots in the rougher wood.

To determine the edge angle you need to measure the thickness and the width, this can be done with a caliper which are not that expensive, you don't need a really high end one to estimate the edge angle on a knife. Divide the thickness by the width and multiple by 60 to get the included angle. This is an estimate of the trig relationship, but will be with a degree for cutlery angles.

For example 0.01" / 0.02" * 60 = 30 degrees included. The exact answer is 28.1 degrees, which is obtained by arctan (0.01 / 0.02 / 2)*2 .

Blademan I look forward to your comments.

Picture attached.

-Cliff
 
Here is an old thread. The part I bolded is of particular interest. So remember these were the days of Rc 61-62. Cliff ground the edge down to 8.5 dps. Just to give an idea of how thin that is, a mora averages 12 dps. The blade rippled but did not chip. Amazing. Thought you guys might find this interesting.

Cliff Stamp said:
As of late I have been doing some chopping with a BM-E (early one bought when they first came out), and my SHBM. Now my BM isn't exactly standard, it is 0.275", no clip to the point, and weighs 660 g. I have also significantly changed the edge profile, so I wasn't looking at the raw performance as much as looking at how they handled, to check out the new grip mods mainly. More on that later.

I started off cutting some fresh wood, mainly pine, that went ok. Later on I switched to scrap lumber as I didn't have as much free time, and had to fit in chopping whenever I got a free half hour or so. This is when the surprises started setting in. I could not keep a working edge on my BM. The edge would constantly roll to a visible degree, you could see it bend or ripple. To be specific these were just barely visible by eye, the steel was 0.005" to 0.010" thick behind the bend.

Now the ripples were easily removed with a little pressure, no chipping as I would have expected. However I was not overly pleased by having to stop chopping every half dozen blocks (I was using mainly 4x4 and 6x6 posts), to fix the edge. Now I knew that the edge was much more acute than standard, but from memory, the last time I checked it, it wasn't that thin that I would expect the the damage to set in this frequently.

The last draw was when I went back to fresh wood and during bucking some spruce I whacked the knife into a knot in the worst possible way. It was kind of "movie-like" as I oculd sort of feel the chop happening in slow motion. I knew it was going to be bad and when it hit the knot I didn't have to check the edge to know it was going to be dented. Sure enough it was rippled to this time about 0.020" thick.

I straightened it with a nail set and a hammer and then adjusted the profile slightly by adding a convex taper to the last one mm or so of edge. I then checked the edge profile to see how much I had thickened it. It spec'ed out at ~11 degrees per side in the last bit of edge. This took me back because that is where I thought it was before I just altered it.

So I check the primary edge profile and it is ~8.5 degrees per side. Ok, now I understand why it was rippling so easy (relative of course, it only got damaged on knots with full heavy swings). This was a flat bevel, no convex taper, on a heavy blade balanced knife. Not bad at all. And of course, no chipping and all damage was easily repaired with the aid of a large hammer.

For those curious, I checked my notes on the ~8.5 degree mod, I did this to check just how much damage would be induce with wood working as I figured that INFI would set a solid benchmark. I was trying to figure out just how low you could go and still be functional. I seems that a sub mm micro-bevel would be enough for all but the worst impacts.

-Cliff
Click to expand...
 
Why was Cliff banned here, does anybody know for sure? Always seemed to me to be a great source of information/perspective, yet so many seem to hate him for it. I guess nobody likes to hear that which challenges common beliefs, perhaps….. :confused:
 
Yes, the ergos had the same hardness as the straight handles.

Yes, Cliff was banned
 
Cobalt said:
Here is an old thread. The part I bolded is of particular interest. So remember these were the days of Rc 61-62. Cliff ground the edge down to 8.5 dps. Just to give an idea of how thin that is, a mora averages 12 dps. The blade rippled but did not chip. Amazing. Thought you guys might find this interesting.
Click to expand...

Cobalt was it after the Ergo series that the hardness was switched from 60-62 to 58-60?
 
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