Cutting, Chopping, and Bending

M

me2

Joined
Oct 11, 2003
Messages
5,109
I've been wondering what sort of knife it takes to pass the free hanging rope cut, the 2x4 chop, and the bending test used by the ABS. These tests get a lot of attention and are the only performance tests used by a judging body that I know of right now. On a whim, I decided to try an Old Hickory knife I have from the local flea market. It's an 8" butcher pattern, and was sharpened on a 220/1000 grit stone, then microbeveled on the 20 degree slots of the Sharpmaker. Right now it's gone through 2 of 3 for the tests, having cut a 2x4 twice and still shave hair off my arm, and having flexed/bent 90 degrees and not broken/cracked. I don't have any rope, so as soon as I get some, we'll see what happens. I've discussed this before on other forums, and while I know a stamped, stock removal blade cannot pass the ABS tests, since it isn't forged, it's nice to see they can compete on a performance basis, though I'm sure many smiths view the journeyman tests as just a starting point.
 
If you look at some of Cold Steel's advertising/demonstration videos, they do many of those tests. You can find them on YouTube.
 
Yea, but I've not seen one pass the 90 degree bend test, and they've not tested for arm shaving after going through the 2x4 on the ones I've see. I got "More Proof" or one of the more recent ones with a purchase.
 
Me2...I think the abs test is more or less used as the bare minimum of what a knife should be able to do or a starting point in a smiths "journey"

Ed Fowler and Kevin Chashen both speak on this subject if you has google fu
 
The ABS performance tests have not been up-graded since Bill Moran set them up in the early 80's.
They are a bare minimum, we have learned much more in the past 30 years and still have more to learn.
 
From what a lot of makers have posted, the test is more to see that the maker can forge the steel cleanly without damaging it and differentially harden/draw back the spine. Not enough wood or rope is cut to really test the steel for edge holding, and a through hardened blade won't do well on the bend test. Soft, relatively thin steel at the spine will bend under low force, and a moderate amount of martensite at the edge will handle the cutting.
 
Hardheart: You are essentially correct, it is possible to pass the Journeyman performance test with a stock removal blade, but the properly forged blade has much more potential than the test reveals.
 
The Journeyman test is designed to test the technical ability of the smith to create a blade with specific requirements. Using it as a standard for knife performance in general is taking it a bit out of it's context. The 90 degree bend is a perfect example of this, it does not measure the amount of lateral force that the blade can withstand, just whether it can survive 90 degrees of deflection without complete fracture/seperation. There is little to be gained in the way of comparative value without that type of data.
There is also no requirement for the blade to be useable after the bend test, which indicates how much relation the test has to real-world use.
 
So essentially, all the smith has to do is not mess up and the knife will be able to pass the test?
 
For many the object is to simply pass the test, others challenge it with the best blade they can make.

I feel that the simple addition of a torque wrench to the bend test would provide a real challenge for those who decide to accept the additional challenge and provide additional knowledge to be gained from the test both for the maker, but also for the consumer.

There need be no minimum torque required at first, but if the force required to flex the blade to 90 degrees was evaluated it would definitely add to the parameters evaluated and just maybe better blades in the future.
 
It would be nice to know the effort it takes, but without restrictions/guidlines on thickness, each knife couldn't be compared to another. I'm still working on the calculations for the bending we talked about in another thread. I'm just having to relearn it from scratch, like starting in chapter 1 of 7.
 
Mr Fowler,
What kind of torgue rating do you think would be a good starting point??

Bending the blade by hand pretty much would void the test in my opinion
 
me2- there is a lot to it, From memory as I can't lay my hands on the reference immediately (will check), for every increment in convex there is a 16 fold increase on resistance. When I find the book I will respond again.

For a camp knife that a man might have to depend on - such as the ABS Specks for the test blade I would suggest a minimum of 70 foot pounds of torque and the blade should return to within 15 degrees of straight after the first 90 degree flex.

While that may sound like a stiff suggestion, I assure you it is child's play for a blade-smith's who is serious about his product.

Years ago I made the suggestion to the ABS, I never got a response.
 
if you look on youtube videos for knifetest.com by noss via the knife destruction test, it will show you some knife bending stuff.

me2 said:
Yea, but I've not seen one pass the 90 degree bend test, and they've not tested for arm shaving after going through the 2x4 on the ones I've see. I got "More Proof" or one of the more recent ones with a purchase.
Click to expand...
 
me2 said:
So essentially, all the smith has to do is not mess up and the knife will be able to pass the test?
Click to expand...

The smith has to make a blade with decent cutting geometry (rope test), a relatively hard edge (2x4/shaving test), and a blade that is resilient enough to withstand a 90 degree bend. The test is designed to be impossible to pass with a blade of homogenous heat treat, if the entire blade is hard enough to pass the 2nd test then it will fail the 3rd. So the point is to prove that the smith can successfully produce a blade with differential hardness, and imposes a rough requirement for the hardness of the cutting edge (the 2x4/shaving test).

I am not aware of any proof or credible evidence that a forged blade has any superiority over one made by stock removal. The ABS is certainly not where I would look for objective information about that subject. I make blades by both methods and have no reason to plant a flag for either. Those who claim that forged blades are superior invariably have their personal reasons for saying so, but never seem to offer any conclusive proof.
 
Justin King said:
The smith has to make a blade with decent cutting geometry (rope test), a relatively hard edge (2x4/shaving test), and a blade that is resilient enough to withstand a 90 degree bend. The test is designed to be impossible to pass with a blade of homogenous heat treat, if the entire blade is hard enough to pass the 2nd test then it will fail the 3rd. So the point is to prove that the smith can successfully produce a blade with differential hardness, and imposes a rough requirement for the hardness of the cutting edge (the 2x4/shaving test).

I am not aware of any proof or credible evidence that a forged blade has any superiority over one made by stock removal. The ABS is certainly not where I would look for objective information about that subject. I make blades by both methods and have no reason to plant a flag for either. Those who claim that forged blades are superior invariably have their personal reasons for saying so, but never seem to offer any conclusive proof.
Click to expand...


I tend to agree there, a blade can be made exceptional using either method if the craftsman is good at what they do.
 
I found the reference: :For a cylinder,resistance to bending follows the fourth power of its radius.; doubling the radius gives a full sixteen greater rigidity. Or, looked at the other way, a simple kind of bending joint can be made my judicious local thinning. Normally a sideways force on the top has its greatest effect lowest down.

Cats Paws and Catapults, by Steven Vogel, page 101.


This is part of the reasoning behind what we call the modified Michael Price Grind. The examples can be found in nature in many venues.
 
You must log in or register to reply here.
Back
Top