Extended Cutting Test

M

me2

Joined
Oct 11, 2003
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Just thought I'd post some stuff about an edge holding test I've been doing. I started with a Food Network damascus (like Shun but cheaper) 4.5" blade Deba-ish knife, 1/16" spine, full flat grind on a 1.25 inch wide blade. I sharpened it on a SiC waterstone at 17 degrees (34 included) per side and then microbevled at 20 degrees on the Sharpmaker, down to the white Fine flat stones. It would catch hair above my arm and split hair held between my fingers.

Now the cutting part. I started cutting soda cans, ~4" long cuts with 3" of blade, about 15 lengthwise cuts per can. My goal is to see how long it takes to dull the blade to the point that it wont cut paper anymore. I am not making much progress. I've gone through a 12 pack of Mountain Dew, 180ish cuts, and it will still push cut copy paper. It slices paper with ease. It will still shave hair off my arm. And I have to keep cutting cause I cant sleep since I drank a 12 pack of Dew. I'm 3/4 of the way through a pallet of 2x4s now, hopefully I'll get tired by the end and can get some sleep.

Seriously, 175-180 cuts in aluminum and this thing still shaves hair off my arm. It lost the hair whittling edge within the first couple dozen cuts, but now seems to have leveled off and I cant detect any change since about can number 5. I'm going to keep trying, but as the caffeine builds up, my cutting speed goes up and heat may become an issue.
 
Are you laying the cans down and cutting them through the side, or top to bottom through the seam? Caffeine can be a bugger, can't it? :D
 
I just hold the can in one hand and cut from top to bottom with the knife in the other. I can get about 15-18 cuts from one can.

This does indeed seem like very good performance. I did the same thing years ago with my Schrade peanut and it was pretty impressive as well. I ran out of cans at 120 cuts with the Schrade, but it would still shave hair and slice paper. This seems to be pretty good steel in the Food Network damascus blades. It came in close to my Griptillian on cardboard. I tried the same tests with my Delica as well, with basically the same result, that is to say I cut a lot of aluminum before the edge dropped below the ability to shave hair from my arm. I didnt check the Delica on cutting printer paper.

My intent was to show that very sharp polished edges were not as fragile or fleeting as people seem to think. I suspect that many reports of polished hair shaving edges going dull in one or 2 cuts is due to a burr that remains on the edge, then breaks off during the cuts.

This seems to be one of those cutting tests that favors high hardness and polished edges. I tried some RADA cutlery knives a while ago and didnt get this good a performance, but it was better than I expected. I'll have to repeat those and see how they faired now that I have some frame of reference.

I did another 25 cuts or so and the blade will still shave hair from my arm. It did start to catch a little on the paper, but still push cuts right next to the point of hold and slices paper very well. I'm up to about 200 cuts now.
 
Are you doing stab and push cuts or saw cuts?
 
Stab the tip into the can just under the little bend below the top, then kind of push the edge down. Its a little weird, but for a 3.5 to 4 inch cut, I use about 3 inches of blade. Its a lot like push cutting cardboard or paper, just more force and tougher material.

I do not have the ability to post a video right now. I'm posting from a public library computer. I can maybe email a video to you.
 
I ran out of cans, so I bought a 24 pack and started over, this time on my Griptillian, 154CM. The hollow grind on this thing is pretty deep, and the edge is really thin right behind the sharpening bevel. I started off sharpening it the same as the FNK (Food Network Knife). I also started doing thread cutting to test the edge sharpness. I'm up to 90 cuts, 5 cans, and the 154CM will still pop hairs off my knuckles. The tip is even still sharp after all that aluminum puncturing. Thread cutting started off between 20 and 30 grams, and after 90 cuts is only up to 60-70 grams. It still shaves hair, still push cuts copy paper, and frustrates my efforts to dull it. Apparently, cutting thin gauge aluminum sheet is not that tough on a knife.
 
Sometimes I've wondered if cutting aluminum cans isn't more like a controlled tearing of the material.
 
Very impressive performance from the knife, but I'm worried about your health if your drinking all that soda. Take it easy.
 
Could be a controlled tearing. I dont really have any way to know. I got up to 144 cuts and the blade is just now up to 90 grams.

No worries. Its spread through several people and about a month.
 
I did some more tests after dinner. It's really getting rediculous now. 254 cuts and the Griptilian still shaves hair off my knuckles, push cuts copy paper, easily slices copy paper, and from my last post, the thread cutting pressure has gone from 60-70 only up to 80-100, with some odd cuts that are back down in the 50 range, all in grams. No sign of a burr or rolled edge on either side, no light reflecting from the edge that I can see. I need to try if full daylight. I'll be a diabetic if I try to test my M2 hacksaw puukko knife. I don't really want to try my Cara Cara. For crying out loud, I'm cutting metal. On the other hand, I'm slowly loosing my need to carry a hair whittling blade. For the Grip and the Delica, it looks like going from hair whittling to paper cutting sharpness should take several weeks of EDC type use, if not a few months. I need a high end trapper pattern with the clip blade sharpened to a razor edge, and the spey blade sharpened that way initially, but not resharpened until it wont cleanly slice paper. At this rate, that might be March or April.
 
You're cutting aluminum cans. Any idea how that compares to cardboard in terms of how many cuts you could do before losing the edge?
 
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