806 Didn't cut it.

E

Eric J

Joined
Oct 29, 2005
Messages
392
This is not a flamestarter. This past Sunday I took my 806D2 Axis (Benchmade) out to use during gardening chores. I sharpened it on my sharpmaker first as it was dull. It left the house shaving sharp. The knife had never been used before Sunday. It has been sitting in my display case since I bought it. I found that it dulled quickly and was not up to cutting grasses that my edger left behind. I noticed how dull it was when I tried to cut some plastic string we put out to block off our seedlings from needless trampling. My wife also tried to use it and found the same results. It took just a few stabs into dirt (no rocks or pebbles) to dull the blade. This knife was a disappointment. I own other BM's and never encountered this before. It obviously has too thick of an edge and needs to be reprofiled. Frustrating to say the least. I'm off to sharpen it now. Don't know what I'll end up doing with it. There were no lock issues.
 
Dirt in general is fairly abrasive, you have other knives which had better edge retention under similar conditions?

-Cliff
 
Mmmmm.

Did it have a burr that folded over? Mine sometimes burrs up; it'll shave and then I'll cut something and it'll fold over. I look and see that "shine" on the edge and feel it with my thumb nail.

I do agree that for daily use the edge needs reprofiling (unfortunely, a too common trait in "heavy use" folders).

But then again, it could be a heat treat issue. Such things happen.
 
Mmmh, BM isn't exactly famous for their edge profile but the 806D2 that I got to handle over x-mas (belongs to a friend of mine) could hardly be faulted for its level of sharpness.
 
I made the mistake of using a Military, with 440V blade, to cut some pine roots in my wife's flower bed. It took me over an hour to restore the edge - much of which was due to considerable edge-chipping.

Dirt = rocks of varying sizes. Even Cliff doesn't attempt to cut rocks in his test-to-destruction reviews.

I also have a BM 806D2. It takes and holds an excellent edge in any reasonable application - but you won't see me digging in the dirt with it!
 
I've dug in the dirt with mine (when I see a pretty flower out in the middle of nowhere, I sometimes "grab" it to plant, great gifts too).

It seemed to do okay. But then I expect to have it loose some sharpness.
 
The dirt I dug into was super soft. There were no rocks in it as it had been sifted. I would expect some sharpness, but not after less than 10 pokes. My wife was shocked. I am not sure what the cause of this was. I will try some more cutting with it to see what happens. Perhaps it was just lacking out of the box sharpness.
 
gud4u said:
I made the mistake of using a Military, with 440V blade, to cut some pine roots in my wife's flower bed. It took me over an hour to restore the edge - much of which was due to considerable edge-chipping.
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With a Sharpmaker or similar or x-coarse benchstone?

Even Cliff doesn't attempt to cut rocks ...
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Usually not, but have on occasion, such as awhile back there was a review of a pATAK where it broke and McClung heavily tore into the guys doing the review highly exaggerating what they did, I then did everything he ranted using a Howling Rat including attempting to chop up a rock.

I dig a fair bit with most knives, for many reasons, like anything it is sensitive to method and once you learn how to do it the stress on the knife goes way down. I have cut a fair bit of sod with a 1/16" paring knife with a high hollow grind made from 1095 at 66 HRC.

I have chopped into rocks on many occasions using long blades clearing brush, spend 15 minutes getting a machete all nice and sharp and blam it into a rock within 60 seconds of starting, break out the file.

Eric J said:
The dirt I dug into was super soft. There were no rocks in it as it had been sifted.
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That sounds abnormal, even if the ground is full of rocks, you tend to have to push pretty hard to dull the entire edge. Many initial edges are burred, burnt, or otherwise not optimal. It is best to not truely judge a knife until it has been fully sharpened.

-Cliff
 
Cliff, What do you think the cause is or was? My guess is that it was not fully sharpened. Any ideas. The dirt was sifted. My Mother in law grows her own veggie garden. She is Chinese and really watches her stuff. She uses cheap knives for this work all of the time. I think it was a fluke. Any help you can give is appreciated!
 
You can often get poor edge retention on initial edges from knives, factory and custom, the edges are often either burred or over polished, at worst burnt through overheating. Sharpen the edge fully, removing any damaged steel and see how it behaves. If it still goes blunt fast after doing this a couple of time and you are not seeing similar behavior on other knives then the steel is likely at fault which you can see sometimes under light magnification 10-20x.

-Cliff
 
The chipped Military 440V edge was thinned, 22 - 25 degrees included-angle and stropped to mirror-bevels. Effortless push-cuts, just a whispered hiss when draw-slicing newsprint.

A few of the rocks encountered in root-cutting were in the range of .5" to 1" diameter.

This 440V blade is hard. When forming an edge with a coarse diamond hone, I see minor edge-chips if too much pressure is applied at the edge.

Clearly, this was an ill-considered use of this blade.
 
Dirt IS rock. However fine the particles may be, they are still the same material as the rock they came from, similar in effect on a blade to ceramic. Gardening knives meant for rooting or digging aren't also meant to retain a slicing edge.
 
I am not sure if this situtation compares to your but a couple of days ago I sliced open a sand bag with my Delica and got severe edge chipping. The Delica has been sharpened before and has held an edge for a good amount of time while performing all the cuttign tasks i asked for. It only took one cut into the sand bag to completeley dull the upper half of my blade and cause some large chips noticable to the eye. The dirt may have had the same effect but over a longer time because sand is a lot coarser and more "stony", but dirt still is stone but in very fine form.
 
I was using my 806 (with the replacement blade) for similar things, with no problems, even though i was not expecting to get a razor edge back.

For my personal comparision: The Swamprat Bandiccots SR101 (as much as i like the steel for its sharpness) didn´t took so much as the D2 did.

If there is something to cut in the mud, i would always choose the 806D2.

If the problem remains after a full resharpening, contact BM, because the 806 is a great knife. Give it some more chances.
 
gud4u said:
This 440V blade is hard. When forming an edge with a coarse diamond hone, I see minor edge-chips if too much pressure is applied at the edge.
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Is this one of the early ~60 HRC models or the later ~55 HRC ones.

While dirt is rock, it isn't simply the hardness of the media in particulate but the macroscopic compression resistance which determines it ability to damage/blunt a knife.

When the edge of a knife hits a piece of dirt the edge will only compress if the dirt is supported enough by the surrounding material so that it will deform the edge rather than simply be moved.

-Cliff
 
Before mowing, I go over my lawn and dig up by hand any weeds that I notice. My two most common knives for this have been the CV Case large stockman (spey blade) and a Mora. I don't try to keep them shaving sharp when used this way, since they don't need to be for my purpose. They just have to cut through the roots of a dandelion or thistle, which is pretty soft material. With a multiblade like the stockman, you can keep one or two other blades with a nice shaving edge on them if you need to. And the Mora is cheap enough that I have several and can use one for a dedicated purpose.
 
It was part of the series with antennae on the butterfly. I guess it might be pretty early.
 
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