Cardboard cutting........How much cardboard dulls your knife????

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boki_zca

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I tested my bark river bowie in 1085 and cut 45 medium and large boxes of medium and thick cardboard and knife was still shaving hair from my arm with ease.I made about 500 cuts ,maybe little more.I never tested any other knives on cardboard and was wondering how many cuts some of you made with other knives!Brought back this knife tu full razor sharpness with few passes on strop with green compound.Ichopped bunch of wood with this knife and got same results ,no real dulling ...what are your experiences with other blades?
 
I've never experienced a steel that could still shave well after cutting a few cardboard boxes... Are you sure that you didn't cut with the kick end of the knife and shave with the tip? Or that you didn't cut, strop, and then try to shave?

I always hear of these miracle stories, but I've yet to see it happen in real life.
 
I've found thru cutting test that a decently ground & heat treated blade of 440C (edge angle close to 17*) can cut 300 linear feet/inch (more depending on what type grit it was sharpened on) of corrigated cardboard before becoming 'dull' enough to require sharpening. DM
 
no, I didnt strop and the blade was still shaving hair when I was done!Not shaving well but shaving and not just one end but complete blade!
 
I'm a big believer in edge geometry, which can make a huge difference in both ease of cutting, and durability. If the geometry of the grind behind the edge is right, it will both support & strengthen the edge, and will also reduce cutting resistance (friction) through thick/deep material. That translates into an edge that lasts much longer. I realized this when I took an old Buck 112 with a pretty thick factory edge on it (which dulled fairly quickly, so I put it away for a long time), and convexed it on sandpaper up through 2000+ grit. That knife is the best cardboard cutter I have now; a completely different animal from the original 'factory' edge. That blade was 440C, by the way. I've also noticed similar results with another Buck 112 in 425M, also convexed in a similar fashion.
 
This saber convex grind cuts really well all materials soft and hard....and edge is strong no dents or rolls when chopping wood etc!
 
Unless I have no choice, I use a utility knife for cardboard and my EDC(s) for everything else. So not much help. But I will say that even using an Endura 4 FFG for three large cardboard packing boxes - approx. long 10 cuts per - I noticed a big difference requiring an edge touch up.

Maybe I just ran into tough card board?
 
I notice that with my benchmade folders too that are in 154cm.This 1085 from bark river seems to have much better heat treatment and also sharpens easily!
 
jacksterp said:
Unless I have no choice, I use a utility knife for cardboard and my EDC(s) for everything else. So not much help. But I will say that even using an Endura 4 FFG for three large cardboard packing boxes - approx. long 10 cuts per - I noticed a big difference requiring an edge touch up.

Maybe I just ran into tough card board?
Click to expand...

That's a big variable too. Not all cardboard is created alike. Most is made from recycled products, which basically means anything might be in it (like dirt or other hard/abrasive material).
 
Obsessed with Edges said:
(Cardboard quality & condition is) a big variable too. Not all cardboard is created alike. Most is made from recycled products, which basically means anything might be in it (like dirt or other hard/abrasive material).
Click to expand...
Another variable is how impacted with sand, grit, gravel, & other funky stuff the surface of the cardboard is from sitting/sliding around on concrete, truck beds, in storage, etc.

IME some cardboard is clean enough to have a large box or three can get cut with ease and little dulling of the knife edge. Other times the cardboard seems to quickly remove the slitting quality of the edge and reduces the box breakdown to hacking & slashing (ineffectively) & tearing at the material.

OWE, when you convexed that Buck did you thin the edge as well as changing its geometry? Or was its "after" thickness pretty much the same as it was originally, though with a convex edge now? TIA.
 
the knife i call k II cut up a 40 gallon water heater box into small pieces and another box that a radial arm combination saw came in and it still shaved hair after cutting all that. if we had a couple more boxes like that i would imagine it would have cut up them too.
 
The edge on a Spyd Millitary can handle a significant amount of cardboard and still shave.
"Normal" cardboard that is...
 
I have to agree, geometry is huge. From my very limited experience with cardboard and convex grinds, the bark river style edge will cut far far longer than just about any other style edge. Its probably the ideal cardboard cutting geometry. I'd think that the grind/geometry has far more to due with the ability to keep an edge than the type of steel when cutting those type materials.
 
HuntBomb said:
The edge on a Spyd Millitary can handle a significant amount of cardboard and still shave.
"Normal" cardboard that is...
Click to expand...

???

You mean single-ply cardboard, the kind with 1... I can't remember the name of the wavy "WWWW" shaped thing is called... that?

I just had my Para-Military 2 hair-splitting sharp this morning. I took down about 6 small boxes, and it can no longer shave hair. I don't have a single knife that's able to shave after this amount of cardboard cutting.

Can someone take a video of all of this cardboard cutting and shaving afterward? I have to say that I'm not a believer, because I have been searching for a steel that can do this since I got into knives, and I haven't been able to find one!
 
Well, not bragging or anything but...opened 2 cases of paper towels at work today with a knife that can usually pull hairs from the back of my hand, and afterwards felt like nothing moar than a weight in my pocket=) srsly though, didn't even touch much actual cardboard. (mostly tape) It was a crkt Urban Shark lol
 
IME you should be able to cut 20-30 feet with no real wear. As others have mentioned, geometry and grind play a major role. Also, if the box is sealed with plastic tape instead of reinforced paper tape, the adhesive will seem to wreck many an edge - wash it off with denatured or rubbing alcohol and you're back in the game.
 
I will try to tape it next time, and I was amazed myself when knife still shaved.It wasnt couple boxes cut to pieces but 40!!
 
RokJok said:
Another variable is how impacted with sand, grit, gravel, & other funky stuff the surface of the cardboard is from sitting/sliding around on concrete, truck beds, in storage, etc.

IME some cardboard is clean enough to have a large box or three can get cut with ease and little dulling of the knife edge. Other times the cardboard seems to quickly remove the slitting quality of the edge and reduces the box breakdown to hacking & slashing (ineffectively) & tearing at the material.

OWE, when you convexed that Buck did you thin the edge as well as changing its geometry? Or was its "after" thickness pretty much the same as it was originally, though with a convex edge now? TIA.
Click to expand...

Yes, I did go shallower with the angle. Convexing tends to make an edge a bit 'thicker' if some deliberate effort isn't made to keep the angle conservatively shallow. The edge is a bit thinner than before, but the convex shape of it has really helped it hold up. And at the same time, the rounder, smoother shoulders of the bevel really make cutting thick material much slicker. Polishing the convex has helped with that also. That's what I was attempting to speak to, in my earlier reply regarding edge geometry.

Here's the knife I mentioned, a Buck 112 '2-dot', 440C blade, shortly after I'd convexed it; it's even a little more refined & polished now. ;) :
 
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