Testing edge-holding ability?

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KC8QVO

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Apr 7, 2011
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What methods are there to test edge holding ability? Are there any materials that can be cut that will "work" the edge pretty hard, without too much risk of damage?

I would like to run my knives some way that I can logically compare them. Carrying one for a week and swapping around to different blades for different weeks won't give me a uniform enough comparison to base anything off of.

For example, I tried slicing cardboard this evening. In the amount of cardboard I sliced I didn't see any real degradation of the sharpness of the knife I used. If there is another material I can cut that will be harder on the edge then I can run, say, 35 slices on each blade and compare the before/after sharpness in ability to shave paper that is what I am looking for.

I have seen methods for deliberately taking an edge off, but this isn't what I am after.
 
When you test edge longevity you MUST test to dull or you will be wasting your time. A consistent material is manila rope (I like 3/4in) and is used by many for testing a edge because it wears at the edge evenly and consistently. Testing just one time doesn't do much either, it takes repeated testing of a single blade typically at several angles to determine the true performance of that single steel on that individual knife.
 
You must have started doing some cutting. Sisal rope is a good test medium. I wouldn't just test one several times, (although you could). I'd test several blades of that steel all from the same maker, sharpened on different grits (this is the only variable I'd change) and different types of grits all at the same edge angle. You'll be very surprised at the results. You'll need to purchase 5-600' of rope as it takes a lot of cutting until the good steels start to skate. Procuring a kevlar gloves is a good move as well. DM
 
In the CATRA testing I performed it was shown that edge finish has little impact on edge longevity. It will change how the edge cuts but the wear resistance and ability to resist deformation is a constant in the steel you cannot change. Between a 320 mesh edge and a 8000 mesh edge the difference in edge longevity was about 3%.
 
You have a CATRA? As those run 10 grand. Or access to one? I've witnessed them at work and its all push cutting of cardboard with alittle movement. They could measure more pressure as it begans to cut less layers of cardboard as edge dulling effects. Plus, blade edge thickness has a big affect on this action. Plus, real world testing like skinning a few deer or cutting sisal rope and CATRA tests are not the same as major differences immediatly appear as this cutting is conducted. I was merely wondering as 3yrs. ago you would not post your test parameters or findings. Whereas I defended mine. DM
 
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My CATRA testing was recent and I assisted a tester that has been doing it for 20 years. It's silica impregnated paper with a constant force applied as it performs saw cuts not push cuts. It's much different than you think. (The machine is 100k by the way)
 
KC8QVO said:
What methods are there to test edge holding ability? Are there any materials that can be cut that will "work" the edge pretty hard, without too much risk of damage?

I would like to run my knives some way that I can logically compare them. Carrying one for a week and swapping around to different blades for different weeks won't give me a uniform enough comparison to base anything off of.

For example, I tried slicing cardboard this evening. In the amount of cardboard I sliced I didn't see any real degradation of the sharpness of the knife I used. If there is another material I can cut that will be harder on the edge then I can run, say, 35 slices on each blade and compare the before/after sharpness in ability to shave paper that is what I am looking for.

I have seen methods for deliberately taking an edge off, but this isn't what I am after.
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Cut cardboard with a steady steer away from the holding hand. e.g. right hander - steer the knife to your right, resulting in curved strips. Steering (a steady twist) introduces edge deflection force which induce edge roll, essentially amplified the dulling effect. My Endura vg-10 started smooth shaving convex edge, after right-steered 10 slices, it catches when cross-grain cut newsprint. Micro-bevel certainly will help but it's a tradeoff - another topic altogether.
 
KC8QVO said:
What methods are there to test edge holding ability? Are there any materials that can be cut that will "work" the edge pretty hard, without too much risk of damage?

I would like to run my knives some way that I can logically compare them. Carrying one for a week and swapping around to different blades for different weeks won't give me a uniform enough comparison to base anything off of.

For example, I tried slicing cardboard this evening. In the amount of cardboard I sliced I didn't see any real degradation of the sharpness of the knife I used. If there is another material I can cut that will be harder on the edge then I can run, say, 35 slices on each blade and compare the before/after sharpness in ability to shave paper that is what I am looking for.

I have seen methods for deliberately taking an edge off, but this isn't what I am after.
Click to expand...

A lot depends on the steel or steels you want to test.

Cardboard works fine depending on what you are testing for, Manila rope works better, 5/8" or 3/4" would be best.

The better steels like S90V will cut for a very long time so that will take a lot of cardboard or rope.

Cardboard isn't very consistent so make sure you get it all from the same place and the same kind of cardboard.

Examples...

Spyderco South Fork in S90V on cardboard..

DSC_35181.JPG


DSC_35201.JPG



Or same knife on 5/8" Manila rope... 500 slicing cuts...

DSC_35171.JPG
 
Jim's been at it again! hey when are going to get some new vids brother? :D
 
Ankerson, Great photo. A good steel sharpened at sub 300 grit will cut a Lot of sisal rope. Much more than a knife sharpened at 2000 grit. DM
 
Ankerson said:
A lot depends on the steel or steels you want to test.

Cardboard works fine depending on what you are testing for, Manila rope works better, 5/8" or 3/4" would be best.

The better steels like S90V will cut for a very long time so that will take a lot of cardboard or rope.

Cardboard isn't very consistent so make sure you get it all from the same place and the same kind of cardboard.

Examples...

Spyderco South Fork in S90V on cardboard..

DSC_35181.JPG


DSC_35201.JPG



Or same knife on 5/8" Manila rope... 500 slicing cuts...

DSC_35171.JPG
Click to expand...

Holy cow! That was all cut on one sharpening? I need to watch your videos.
 
Howdy,
Love your reviews! Do you have any idea as to the HRC on that fine piece?
Can't seem to find it listed anywhere. Also what is you prefered sharpening approach to the S90V?
Thanks....
 
Ray Allen said:
Howdy,
Love your reviews! Do you have any idea as to the HRC on that fine piece?
Can't seem to find it listed anywhere. Also what is you prefered sharpening approach to the S90V?
Thanks....
Click to expand...

I believe they are in the 60-61 HRC range.

Like to keep a semi polished edge on S90V, around 14-16 Microns or so, leaves a nice aggressive edge, but not too toothy so it drags.
 
Ankerson said:
My videos aren't that long. LOL

But yeah that cardboard was cut in one sharpening and the rope in another.
Click to expand...

Jim, What sharpening methods do you use? Do all Spyderco knives hold the edge like yours? Sorry for all the questions I'm a newbie.
 
LEE IN VA. said:
Jim, What sharpening methods do you use? Do all Spyderco knives hold the edge like yours? Sorry for all the questions I'm a newbie.
Click to expand...

They will if you are good at sharpening. :)

I use the Edge Pro to set the bevels then touch up by hand on a strop after.
 
Guys its really not that difficult and it doesn't require S90V to cut a lot of rope. Just sharpen your knife at 15-16*, strop off the burr and start cutting sisal rope. When I cut I use a vise to hold the rope and a kevlar glove. The knife I'm holding is a Buck 110 with cpm-154 steel, sharpened on a x-coarse dmt stone and it made 2000 cuts on 1/2" sisal rope before it started to drag. DM
100_2484.jpg
 
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