Serrations and push-cutting.

philthygeezer

philthygeezer

Joined
Aug 6, 2002
Messages
746
Seems to me I read at one point that serrated edges were better for push cuts because the tips of the serrations 'bit' into the medium with high local force, and then the curves of each serration allowed for a kukri-like slice of the medium on a much smaller scale.

Indeed when cutting with the serrated portion of my Delica, I push right thru rope instead of sawing at it. This leads me to believe that there is a vast difference between Spyderco serrations and that of the average steak knife. These serrations may not give a smooth flat surface upon cutting but they seem to cut more efficiently. I am not so sure about wood though.

The impression I get from reading all of the serrated vs non-serrated posts/articles is that plain edges push-cut and serrations saw. However I have not experienced my first serrated pcket knife in this fashion.

Can anyone comment about experiences push-cutting with serrated knives, especially Spyderco's. Am I the only one that thinks serrations help push cuts?
 
Well, there's push-cutting, and then there's push-cutting. When I open an envelope with a serrated blade, I catch the paper in one of the serrations, and pull the knife, which push-cuts the paper and opens it like a zipper. Serrated blades zipper-cut well when the material being cut is a much smaller diameter than the scallops.

For regular push-cutting, like trying to push-cut rope, serrated blades sometimes work. It's not because they're serrated, IMO. It's because they're sharpened at around 20-degrees inclusive -- when they do work for push-cutting, they work because of the small included angle, and despite the serrations. With factory plain edges often coming in at 40-50 degrees included, and left otherwise thick, they sometimes don't push-cut well. But it doesn't take much to make a plain edge way out-push-cut a serrated edge. A plain-edge blade, razor polished at 30 degrees inclusive, will blow away a serrated edge for push cutting.

I just tried this right now with two serrated blades and two plain edge blades (endura plain, endura serrated, calypso jr. plain, SOG Night Vision partially-serrated). In thin, soft rope, the serrated edges can slip through the rope no problem, especially when I push-cut by looping the rope in my hand and pushing. On a cutting board, the serrated edges can push-cut also, though they leave the last little bit of rope uncut. The plain edges, which have my 15-degree edge with a light 20-degree double-grind on them, also work fine, and cut a bit easier than the serrated edges.

In thicker, tougher rope the plain edges pull way way ahead. The serrated edges don't want to penetrate for push cuts, the plain edges make their way through almost half way. Just the fact that I lowered the edge angle and polished the plain edge a bit was all it took for the plain edge to pull well ahead for push cutting.

Joe
 
You must log in or register to reply here.
Back
Top