Blade testing

C

Chad Michael

Joined
Oct 2, 2016
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67
Good morning guys n gals. Anyone know of someone I could send a knife to to do some edge retention testing for me? Or does anyone here want to do it for me. The blade is s110 at 63-64.


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Chad,
Most folks just test the edge themselves. There isn't a "standardized" test for edge retention with a number or rating.

Cut some stuff that the blade is intended to cut .... cut a lot of it. If the edge still looks good under magnification, and stays sharp, then re-sharpen and test it on some tougher things like cutting sisal rope. See how many cuts it will make before it becomes noticeably harder to make a cut.

Remember that the edge hardness and HT results is only part of the edge retention. A major part is geometry. A thin edge on a chopper will have poor edge retention even with a perfect HT. A 30 degree edge on a fillet blade will last forever ... but won't cut fish worth a darn.
 
cut things people would normally cut, cardboard, rope, zipties, wood, wire/cables, food etc.
 
you can try Ankerson here on the forums, but he is pretty busy, and selective
It's very time consuming to do a proper test
He does it for himself so he may or may not be interested in your knife.
 
Thanks for the replies. I have cut up cardboard but got threw like 800 ft and gave up. I just wanted an unbiased opinion really from someone that knows knives.


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A comparative test is often one of the best ways to check out your HT. Get a similar commercial knife from K-Mart or a sporting goods place. Nothing high end, just a user. Sharpen it and your knife the same and test side by side. Cutting 1" sisal rope is one of the best tests for edge retention. Place the rope on a wooden board and make repeated cuts completely through the rope about half an inch apart. Count the cuts. Do the commercial knife first and then your knife. You should be able to tell which knife makes the most cuts before the edge is noticeably dulled. If your knife holds up better, than it is better than the average commercial knife. If it is less, then you have a problem in your HT. If you have access to a knife that you know has a good HT ( from a maker you know and trust), test it against yours.
 
It seems like there should be a standard test for edge retention. I've been thinking about this off and on for months and have a few ideas.
It's going to take a uniform cut, meaning straight up and down, a consistent pressure in the cut, and something to keep the blade from contacting the wood or base so that you have a reliable cutting media throughout the testing.
Now do you do a straight down chop with one portion of the blade, or do you do a draw or push to test a larger section and attempt to mimic a normal cut?

The sisal rope sounds like a great media to use. It would be awesome to have a machine that would make the motions and feed the rope, but that might be a lot to ask.
But it seems like you could get a reasonably consistent test with this, with numbers. It would help eliminate some subjectivity for edge retention.
 
Brock47 said:
It seems like there should be a standard test for edge retention. I've been thinking about this off and on for months and have a few ideas.
It's going to take a uniform cut, meaning straight up and down, a consistent pressure in the cut, and something to keep the blade from contacting the wood or base so that you have a reliable cutting media throughout the testing.
Now do you do a straight down chop with one portion of the blade, or do you do a draw or push to test a larger section and attempt to mimic a normal cut?

The sisal rope sounds like a great media to use. It would be awesome to have a machine that would make the motions and feed the rope, but that might be a lot to ask.
But it seems like you could get a reasonably consistent test with this, with numbers. It would help eliminate some subjectivity for edge retention.
Click to expand...


Perhaps a fixture similar to a one arm paper cutter where you can feed the material and slice down without contacting a solid surface?!
 
Busto said:
Perhaps a fixture similar to a one arm paper cutter where you can feed the material and slice down without contacting a solid surface?!
Click to expand...

Yes, I was thinking you could cut a slot in the cutting board where the blade will pass through the rope, and have a stop at the handle to stop the downward motion.
 
Chad Michael said:
Thanks for the replies. I have cut up cardboard but got threw like 800 ft and gave up. I just wanted an unbiased opinion really from someone that knows knives.


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Click to expand...

What do you consider sharp and what do you consider dull enough to stop the test? You can cut a LOT of cardboard, 3000 ft plus, and still make slicing cuts on thin paper using a cheap kitchen knife. The first thing to do is define your starting and stopping points and make sure your sharpening is consistent and burr free.
 
me2 said:
What do you consider sharp and what do you consider dull enough to stop the test? You can cut a LOT of cardboard, 3000 ft plus, and still make slicing cuts on thin paper using a cheap kitchen knife. The first thing to do is define your starting and stopping points and make sure your sharpening is consistent and burr free.
Click to expand...

That is a really good point as far as testing goes. You would have to have the same blade edge angle, and take it to the same level of polish. slight inconsistencies might be addressed by repeated sharpening/testing for both blades. That would tend to average it out. It also might indicate a sharpening jig is in order to get as close to matching results as possible.
 
me2 said:
What do you consider sharp and what do you consider dull enough to stop the test? You can cut a LOT of cardboard, 3000 ft plus, and still make slicing cuts on thin paper using a cheap kitchen knife. The first thing to do is define your starting and stopping points and make sure your sharpening is consistent and burr free.
Click to expand...

The fastest way to test is kevlar ballistic fabric which is very abrasion resistance .Soft wood board under kevlar and when blade start to push kevlar in wood instead to cut , test is done .This will happen very quickly with any carbonsteel ...But as you say it is still very sharp edge so question is what is dull blade :)
 
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I was thinking of building a test fixture to do this. Not because it's necessary but because that's the kind of thing I've done for a living and I thought it would be a neat project.

Basically a padded vise to affix the knife with solid backing opposite the direction of the cut, traveling on a linear bearing, actuated by an air cylinder set with a given pressure. Whatever the medium being cut, sisal rope, paper, etc, would be supported in a slotted vise. The angle of the cylinder/linear bearing would be set so a standard portion/length of the blade would be exposed to the test cutting in a drawing motion. Say 2" linear motion for the entire vertical travel.

Then it just takes some experimenting to find what the standard pressure should be. Or if a set of pressures are used to determine how long the initial edge lasts, and how long the secondary edge lasts (ie a knife that pops hair until it doesn't, but would cut cardboard forever vs a knife that pops hair much longer, and when it doesn't couldn't cut a wet paper bag).

I was going to use rope because I think it would be the easiest/least expensive medium to use. Then I was just worried about consistency of that medium.
 
me2 said:
What do you consider sharp and what do you consider dull enough to stop the test? You can cut a LOT of cardboard, 3000 ft plus, and still make slicing cuts on thin paper using a cheap kitchen knife. The first thing to do is define your starting and stopping points and make sure your sharpening is consistent and burr free.
Click to expand...

Shaving and passing clean through magazine paper is where I'm happy. I like toothy edges. Which is why I like s110 so much


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You could use fiberglass cloth from the autobody aisle and do the same thing. That'll wreck just about any edge in short order.
 
kuraki said:
I was thinking of building a test fixture to do this. Not because it's necessary but because that's the kind of thing I've done for a living and I thought it would be a neat project.

Basically a padded vise to affix the knife with solid backing opposite the direction of the cut, traveling on a linear bearing, actuated by an air cylinder set with a given pressure. Whatever the medium being cut, sisal rope, paper, etc, would be supported in a slotted vise. The angle of the cylinder/linear bearing would be set so a standard portion/length of the blade would be exposed to the test cutting in a drawing motion. Say 2" linear motion for the entire vertical travel.

Then it just takes some experimenting to find what the standard pressure should be. Or if a set of pressures are used to determine how long the initial edge lasts, and how long the secondary edge lasts (ie a knife that pops hair until it doesn't, but would cut cardboard forever vs a knife that pops hair much longer, and when it doesn't couldn't cut a wet paper bag).

I was going to use rope because I think it would be the easiest/least expensive medium to use. Then I was just worried about consistency of that medium.
Click to expand...

Do you have any designs laid out K?
 
HSC /// said:
you can try Ankerson here on the forums, but he is pretty busy, and selective
It's very time consuming to do a proper test
He does it for himself so he may or may not be interested in your knife.
Click to expand...

No matter how hard I try, I can not draw any conclusion from his tests .I think that real test from whom we can made accurate conclusions is to CUT something very thin .That way we test steel, not geometry of the entire blade ..............
 
kuraki said:
I was thinking of building a test fixture to do this. Not because it's necessary but because that's the kind of thing I've done for a living and I thought it would be a neat project.

Basically a padded vise to affix the knife with solid backing opposite the direction of the cut, traveling on a linear bearing, actuated by an air cylinder set with a given pressure. Whatever the medium being cut, sisal rope, paper, etc, would be supported in a slotted vise. The angle of the cylinder/linear bearing would be set so a standard portion/length of the blade would be exposed to the test cutting in a drawing motion. Say 2" linear motion for the entire vertical travel.

Then it just takes some experimenting to find what the standard pressure should be. Or if a set of pressures are used to determine how long the initial edge lasts, and how long the secondary edge lasts (ie a knife that pops hair until it doesn't, but would cut cardboard forever vs a knife that pops hair much longer, and when it doesn't couldn't cut a wet paper bag).

I was going to use rope because I think it would be the easiest/least expensive medium to use. Then I was just worried about consistency of that medium.
Click to expand...

John, give Aaron Gough a call, you guys will get along great :-)
 
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