Why does paper dull knives/blades?

I have repeatedly heard that slicing paper with a knife is a sure way to dull that knife.

My question is why? How? Clearly the metal of the knife is far harder than the paper. So how can paper possibly have any effect on a metal knife?

Paper contains clay and other hard minerals.

“We can see here in this scientifically accurate animation that each paper molecule uses tiny files to dull the knife blade.”

No, I put this in the “myth” category. Yes, I know that other posters will argue this, but I will stand firm. Cutting ANYTHING tends to dull blades. The softer the material is, the less dulling effect. Remember, printers use (and have used) sliding knife blades to trim bound books and printed materials for hundreds of years. You will not ruin your knife or scissors by cutting paper.

On the other hand, my own sainted mother would chase us around the house if we used her sewing scissors to cut paper.

My wife is the same. We have scissors for paper, scissors for cloth and some in the kitchen that I can use for anything from cutting chickens up to cutting plastic trays to make them fit the bin.

Yes, coated paper contains clay and some other materials, but I am thinking of basic, standard paper. Cutting sandpaper will also dull knives. The clay in coated paper is extremely fine…much finer than a typical sharpening stone. You might as well argue that cutting coated paper will actually improve the blade.

True story…at the age of 101, my grandmother decided that there was excess electricity leaking around her house, so she cut all the electrical cords she could find with a pair of scissors. They looked like wire strippers afterwards, with half a dozen notches on each blade…

A sharpening stone is used parallel to the edge, not perpendicular to it. Just see how fast you can wreck a knife edge with a sharpening stone used incorrectly.

I hope none of you were holding the scissors.

I’m still going to disagree. The clay is bound into the paper surface, which is being split by the scissors or knife blade to then pass parallel to the blade. The actual edge of the blade is not cleaving the particles. They are much too fine. This is not the same as trying to cut a rock.

Besides, the purpose of a blade is to cut, get dull, and be resharpened. If you don’t do all three, the purpose is unfulfilled.

Nope. We would have gotten a spanking for running with scissors for sure.

I have Fiskars scissors I use for cutting out my 4"x7" ebay shipping labels from plain stock non coated 8"x11" printer/copier paper and they are still going strong with no sharpening after slicing (conservatively) at least 5000+ sheets or (14+8 x 5000) 110,000 inches of paper over the years. Having said this the edges of each scissors blade are sharp"ish" but not razor sharp and might not be suitable for delicate textile work at this point while still being great for stiff sheets of paper. Horses for courses.

I also have several knives I use to slice up cardboard boxes for breakdown or shipping re-use and cardboard will absolutely beat the crap out of the edge of even the finest knife steel after even modest use.

http://so-sew-easy.com/cut-paper-with-sewing-scissors/ (the cartoon is amusing)

You can disagree all you want, but then you need to explain how scissors ever get dull if cutting is the same as sharpening.

Did anyone else notice, in that link, that their last cite, the one they considered the most definitive, was just a direct quote of their first cite?

By that logic, diamond dust in saw blades would do nothing, and yet we know that it does.

But I didn’t say that. I said that “you might as well argue…” Cutting anything at all will dull the blade. You are absolutely correct that cutting coated paper will not sharpen a blade.

Blades get dull. That’s to be expected. But to say that cutting paper is a lot worse than cutting anything else (meat? bone? rope?) is just not accurate. What are you SUPPOSED to cut with knives?

This was the question:

Why does paper dull knives/blades?

I never said that cutting paper was worse than cutting other materials, but it’s probably pretty bad, at least compared to fabric or hair. When I cut mats, I do one-cut per edge with my mat cutter (it uses single-edge razor blades). So, it takes me two blades per mat. But, if I don’t, the edges don’t come out perfectly smooth (they get tiny tears at the edges). Note: the edges cut in mat board using this method are as sharp as a knife!

<Peter Lorre voice> It always surprises me how fast human tissue dulls a scalpel blade. </PLV>

I have no idea if paper dulls knives faster than other common substances but I’ll point out that paper cutters and scissor are honed differently than most knives. They have a chisel edge, flat on one side and less taper. Those blades are not meant to flex at all and most knives are. Paper cutters will also be made of harder steel and so are many modern scissors because no lateral force is expected to be exerted on them.

Good point. Using my rolling photo cutter is different from using my pocket knife, for exactly that reason. I hardly ever sharpen (or replace) the wheel on my photo cutter.

I run a dog grooming salon, and I spend hundreds of dollars a month keeping sharp scissors for my groomers. If I see anyone cutting paper with their scissors, there will be some retraining on proper equipment use going on in fairly short order. (I have two pairs of paper scissors around for the times when paper needs to be cut.

The point is, is that paper will not dull knives or scissors all that much, but it will dull them. You will not notice the effect if you use these scissors to cut paper all the time, as paper is not that hard to cut.

But, when you go to cut something else with those scissors, you will notice that they are duller.

Scissors for things like cutting hair are razor sharp. If you only cut clean hair with those scissors, they will stay that sharp for a good while.

Cutting other things, like paper or dirty hair with those scissors will dull them significantly faster. You would still be able to use them to cut paper, but their razor edge that is useful for hair will be too dull, and will bend the hair in between the blades rather than cleanly slicing it.

Also, scissors for hair cutting and other uses that need a razor edge are not cheap. I pay between $200-$500 for a single set of scissors. I paid about $5 for a pack of two paper scissors at office depot.

Use paper scissors for paper. Use the expensive razor sharp scissors for their intended purpose.