Push Cutting Paper

wsfarrell

wsfarrell

Joined
Jun 18, 2009
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199
Apologies if this video has already been discussed; I couldn't find a link to it here.

There is an 8-part series on youtube on how to sharpen a Japanese Usuba. Here's a link to the last part, where the author uses a leather strop to finish the sharpening. If you skip to 3:40, you'll see him test the edge by push-cutting newsprint, except this is push-cutting like I've never seen. Granted, he seems to slice a little to get it started, but that's still one sharp knife IMO.

http://www.youtube.com/watch?v=lV_DX0Z16hk
 
I've seen it done before that way, as well. I'd say it's sharper than a knife that can cut the same paper - but starting where the tension is (hand) and going out. I generally don't cut towards me, so hold the paper from the top and cut from the bottom instead of holding the left and cutting from the right.

Next, cutting circles in newsprint.
 
I've seen fellas measure how sharp a knife is by holding a piece of paper along the top and making vertical cuts in the paper. The farther from the hand you can cut, the sharper the knife.

In the video, I notice that he stiffened the paper by having it bent, but that is still a very sharp knife.
 
Without doubt sharp but the geometry of the blade is also another big factor.

Without bending the paper slightly that type of cut is nearly impossible, if you can do it without bending the paper you are the man!
 
Yup, there is a bit of technique and a bit of "really sharp knife" there. If you are lacking either one, the cut is nearly impossible.

I enjoy practicing making little cuts (like spirals and circles in paper) when I am bored. I find that some of these cuts are very dependent on technique.

I also agree that the geometry of the knife is critical too though.

Here are some cuts I made a while back if anyone cares. I can tell you that this knife is pretty sharp, but that first cut is mostly technique and can be done with a lesser edge if you know how to do the cut.

http://www.youtube.com/watch?v=cActYLNDgxk
 
Slicing, even the faintest amount, totally defeats the concept of push cutting paper IMHO. This is how I normally test an edge, on phonebook paper. If you can push cut paper without any slicing at all, all the other tests pale in comparison except the hanging hair. Those two are the ultimate tests. If you can do either, your knife is about as sharp as it can get. Whittling hair or tree topping arm hair are the same thing in my book, and both are easy in comparison, IMHO.
 
I've not tried the paper test shown, but sometimes I'll fold the end of a piece of phonebook paper so about 1/2" stands straight up and push cut that. Only my sharpest knives can do it. Standing 3/4" off the table I have not been able to do yet.
 
That is slicing, not pushcutting. You can see that he starts near the heel and ends near the tip. Plus he presents the blade at an angle and arches the paper. The knife is sharp, just pointing out some things.
 
That's very sharp! The way that several of us would test would be with either phone book paper or newsprint, and hold it between the thumb and forefinger vertically, and push cut straight down to the floor. I'm usually able to get 4 inches, Gunmike1 would go over 6. Others on this forum can go for 6 as well, IIRC.
 
sodak said:
That's very sharp! The way that several of us would test would be with either phone book paper or newsprint, and hold it between the thumb and forefinger vertically, and push cut straight down to the floor. I'm usually able to get 4 inches, Gunmike1 would go over 6. Others on this forum can go for 6 as well, IIRC.
Click to expand...

That's one sharpening trick I've yet to master. How do you get them to cut that far away? My best is 2 inches after 300, 800, 1200 grit belts, then leather on the belt sander.
 
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