Opinel Blade Failure

[SilverFoxKnows]

It goes back to using the right tool for the right job. Take a screwdriver and pound the bearing cup out of a brake drum. You'll get the cup out. You'll also mush up the tip of perfectly good screwdriver. This is no different.

Frank

 

[Vivi]

It goes back to using the right tool for the right job. Take a screwdriver and pound the bearing cup out of a brake drum. You'll get the cup out. You'll also mush up the tip of perfectly good screwdriver. This is no different.

Frank

It's different as evidenced by the improperly heated blade. A screwdriver with improper manufacturing will fail where a properly made one will excell, this case being no different.

The failure wasn't caused by an improper tool selection but by defective manufacturing.

EDIT: For further demonstration of the blade's softness and lack of durability in regards to other Opinels I own, I took the knife to a plastic kitchen cutting board. I chopped up some carrots and did press cuts into some almonds and other miscellaneous foods I could find. The edge, a portion that was previously undamaged, has rolled, bent and warped significantly, much more so than a dollar store kitchen knife would do. In this case it cannot be argued that the tool was not being used properly, making it further evident that the tool itself is at fault.

 

[SilverFoxKnows]

but I stand by my statement about using the right tool for the right job.

Frank

 

[Cliff Stamp]

... those tools you speak of have blade angles between 30 and 35 degrees suited too taking the shock by adding force.

The Temperance I used to cut the nails has a primary edge of 10 degrees with a 0.1 mm wide micro bevel at 15, obviously then you could go much thinner cutting wood.

Secondly the pressure generated by pushing and impacting on the spine are not the same ...

That is why you use the impact because it provides more force. Yes the edge needs to be increased in cross section to withstand the higher forces. The heaviest wood working knives I use have a 8 -> 14 degree convex sweep and the apex angle is only about 1/64" wide. If I didn't want to subject them to hard impacts the apex would only be about 10 and the primary about 5.

Vivi, if you pop into rec.knives, Alvin has been offering kit blades for some time now. You might be able to get a replacement blade in either 1095 or M2.

-Cliff

 

[canranger]

The Temperance I used to cut the nails has a primary edge of 10 degrees with a 0.1 mm wide micro bevel at 15, obviously then you could go much thinner cutting wood.



-Cliff

So is that 10 degrees total or both sides for a toal of 20 degrees which would it be?

Abe

 

[Dog of War]

An Opinel obviously isn't the tool of choice for chopping ... however Vivi's testing exposed a flaw in the blade's manufacture and may well have prevented him from depending on it for something important.

In this case the knife couldn't even be depended on to perform ordinary tasks for which an Opinel is suited, even hold an edge satisfactorily. IMO this is one justification for pushing a blade beyond its normal scope of use. In the field under difficult conditions, tools do get used for things beyond what the manufacturer probably intended. Do you want to carry a defective tool, or even one that's just barely adequate? If I have a choice, I sure don't.

 

[knifetester]

Vivi, if you pop into rec.knives, Alvin has been offering kit blades for some time now. You might be able to get a replacement blade in either 1095 or M2.

-Cliff

For Opinels?

 

[Cliff Stamp]

For Opinels?

Of that thickness.

So is that 10 degrees total or both sides for a toal of 20 degrees which would it be?

The exact angle floats from 7-8 degrees per side, so about 14-16 total. I have done it with knives which had the primary come down to about 0.010" thick. Like any skill, the more you use it the less demanding it becomes, both on you and the equipment.

-Cliff

 

[db]

Alvins "kits" are basicly very hard blanks that you can profile and grind into what ever you want.

 

[DaveH]

So in summary at this point it seems the blade on the knife in question was too soft.

The question that I have is, given the inexpensive cost for the knife, would consistent heat treat be expected?

IMO, it's not resonable to expect 100% correct heat treat.

So do you worry about it (eg: send it back), or just toss it and buy another?

 

[gator68]

So in summary at this point it seems the blade on the knife in question was too soft.

The question that I have is, given the inexpensive cost for the knife, would consistent heat treat be expected?

IMO, it's not resonable to expect 100% correct heat treat.

Yes, it is reasonable to expect that the heat treat is correct. It is not a knife without a correct heat treat.

 

[Cliff Stamp]

Alvins "kits" are basicly very hard blanks that you can profile and grind into what ever you want.

Lately he has started offering blades in various stages of being finished, some have profiles and grinds and just need handles. If you made a serious case as user he would likely make a replacement blade directly. He would probably be curious how a L6 class steel full hard would work in an Opinel for a guy like Vivi who is a knife user and not pontificator.

-Cliff

 

[Ebbtide]

An Opinel obviously isn't the tool of choice for chopping ... however Vivi's testing exposed a flaw in the blade's manufacture and may well have prevented him from depending on it for something important.

In this case the knife couldn't even be depended on to perform ordinary tasks for which an Opinel is suited, even hold an edge satisfactorily. IMO this is one justification for pushing a blade beyond its normal scope of use. In the field under difficult conditions, tools do get used for things beyond what the manufacturer probably intended. Do you want to carry a defective tool, or even one that's just barely adequate? If I have a choice, I sure don't.

Testing?
Cliffing maybe...but testing?
I'll concede to testing if the OP had quit after the first indications of damage.
After that it is called breaking.

Psuedo science aside, it is an Opinel.
A low budget mass produced inexpensive knife suited for a picnic box.

If it were a RLSS one would hope that the OP would have stopped after the first indication of damage.

 

[David Schott]

That blade isnt heat treated. Even a spring temper should hold up better than that against green wood....im actually surprised annealed steel deformed that badly on wood! Sure it wasnt a steel pipe shaped like a branch? haha!

Unfortunately, this might be a "you get what you pay for" scenario....i disagree with the fact that you should be able to expect optimal heat treating on such a cheap knife.....for the profit margin they are turning on these, im doubting they care too much about perfect heat treating or the time and care it takes to get it right...

 

[Cliff Stamp]

I'll concede to testing if the OP had quit after the first indications of damage.

You need to repeat the work to make sure you are able to interpret it correctly and are just not seeing a spot defect or an interesection of a number of rare effects. To do otherwise leads to the likely probability that you could severely misjudge the cause of the failure. This of course is no different than doing a salt spray test and not stopping at the first sign of rust.

...one would hope that the OP would have stopped after the first indication of damage.

You would never rely on a knife for such uses without having evaluated it fully so that statement is self-invalid. How far you push a knife in a survival situation would also depend on the outcome of not finishing the task. It isn't difficult to imagine a senario where the immediate needs would exceed damage done to the knife.

-Cliff

 

[Vivi]

Vivi, if you pop into rec.knives, Alvin has been offering kit blades for some time now. You might be able to get a replacement blade in either 1095 or M2.

I'll show up there sometime and see what he can do. It would be interesting to compare to the regular Opinel blades.

In this case the knife couldn't even be depended on to perform ordinary tasks for which an Opinel is suited, even hold an edge satisfactorily. IMO this is one justification for pushing a blade beyond its normal scope of use. In the field under difficult conditions, tools do get used for things beyond what the manufacturer probably intended. Do you want to carry a defective tool, or even one that's just barely adequate? If I have a choice, I sure don't.

This failure would of been much more dissapointing if I had just gone out for a week long camping trip. Especially considering an Opinel #12 is designed so that I'd be comfortable carrying it and no other knife due to the scope of work it can preform. Moral of the story? Test your knives before you need to depend on them, and carry along a small SAK for back-up. Two things I generally do.

IMO, it's not resonable to expect 100% correct heat treat.

So do you worry about it (eg: send it back), or just toss it and buy another?

I could accept the blade being slightly brittle or a little soft, but this seems to fall under an extreme that makes the lack of quality unnacceptable in my eyes. My course of action will be continue doing hardness tests on the blade, look into another blade for the #12 handle and in the meantime save up some money to order some new #12's. I want to repeat what I did with another #12 to see how it takes the chopping.

I'll concede to testing if the OP had quit after the first indications of damage.
After that it is called breaking.

I kept chopping to double check these specific motions were damaging the blade, then chopped a few other things for comparison. I also tried to use different parts of the blade to make sure the original target area wasn't the only defective portion. I wanted to try using the spine too, either as-is or shaped to a rough edge on a rock, but the lock had already been damaged by my own error so I had little faith in it.

 

[Ebbtide]

Cliff, Vivi,
You guys have a great future together and will keep the knife companies in business.
Keep up the good "work".
Good luck.

 

[Dog of War]

Testing?
Cliffing maybe...but testing?
I'll concede to testing if the OP had quit after the first indications of damage.
After that it is called breaking.

Psuedo science aside, it is an Opinel.
A low budget mass produced inexpensive knife suited for a picnic box.

If it were a RLSS one would hope that the OP would have stopped after the first indication of damage.

Tests like Vivi's, and pretty much the entire body of Cliff's work, IMO are invaluable to people who take "real-life survival" (is there any other kind?) seriously.

I've carried a bug-out bag for several years now and have spent a lot of time both professionally and personally training and preparing for a wide range of survival situations. My current BOB weighs about 16#, not that much for an athletic 180# person .... still I'm careful about every ounce that goes into it. I've considered Opinels because of weight, but IMO I need something more robust and am willing to make that trade-off. Definitely not a decision to be made lightly.

Of course if you're satisfied from the description you saw on a website that an Opinel's merely "a low budget mass produced inexpensive knife suited for a picnic box" .... well, you can carry three Battle Mistresses and an EdgePro in your bag for all I care, plus a queen size bed instead of a space blanket so you'll be nice and comfy. Others of us prefer to prepare by gaining all the useful information we can.

 

[Cliff Stamp]

I'll show up there sometime and see what he can do. It would be interesting to compare to the regular Opinel blades.

He generally hollow grinds really deep, and by this I mean it makes an Opinel look like a crude wedge in comparison. He also does flat grinds which is what you would want for that type of wood working blade, bandsaw steel, full hard edge, drawn spine. You might also consider writing Opinel, describe the work you have done positively then describe that work, your conclusions, and ask for comments.

-Cliff

 

[Ebbtide]

Of course if you're satisfied from the description you saw on a website that an Opinel's merely "a low budget mass produced inexpensive knife suited for a picnic box" .... well, you can carry three Battle Mistresses and an EdgePro in your bag for all I care, plus a queen size bed instead of a space blanket so you'll be nice and comfy. Others of us prefer to prepare by gaining all the useful information we can.

Well the description of the Opinel was mine.
One that I wrote myself.
I did not see it on a website.
I do not and will never carry a battle mistress or any other blacticle sharpened prybar.
I'm sorry but I don't buy into the marketing, hype, pseudo science or destructive testing.

If you want to believe in the marketing, hype, pseudo science and destructive testing, go right ahead "for all I care"

Chop with an Opinel, or mash potatos with a Buick.
Go ahead, "for all I care"

Knife breaking is not science, no matter how hard the practice is defended.
Now actually using a knife well, that could be a science, but much harder to learn than breaking one.