Hemp rope vs. paper?

Leu Custom

Leu Custom

Joined
Jun 2, 2007
Messages
1,354
I have a question for all you knife gurus out there. Why is it that when I cut paper with my blades, it almost appears a very very small wire edge appears (which I can actually strop off with a cotton t-shirt), but when I'm using it to cut 1" inch hemp rope, almost nothing appears (that I can feel with my thumb nail? Is the paper actually more abrasive them then hemp rope? You would think it's the other way around right? Any information would help!
 
I've always heard that paper dulls a knife quicker than most things. But that could be BS.
 
It all depends upon the paper. Some papers are more pure (as far as being just pulp) that others, while some have a lot of silicates and other contaminates. Many cardboards I have cut behave as if they were recycled from sand paper. Both paper and rope are soft fibrous materials with an abrading ability. However paper has the tendency to have more of a solid material affect on the knife edge, while rope attacks things more selectively on the microscopic level.

Tim Z. and I spent quite a bit of time a couple years ago applying cuts to different materials under identical loads with many different steels and then examining the edges under the microscope as they degraded. Hard cardboard was the meanest to edges, and your heat treat had better be on to tackle it. Rope however was very different. Rope would take blades that were entirely inferior on the cardboard and actually increase the cutting ability and duration on rope by the way it selectively tore out chunks of the edge making nasty jags. When we saw blades with awful inconsistency, weld flaws, and very disappointing Rockwells cutting rope like a laser after a few strokes, we started to understand why so many smiths have a fondness for this test medium when it can be skewed to make certain blades look so good. We also pretty much abandoned it ourselves as a test medium due to this and the countless variables that made standardized data very difficult to obtain with it. Rope, whether hanging or on a bench top often tells you more about the hand doing the cutting than it does about the blade.
 
Then why do some makers refuse a challenge to rope cutting as I have heard at knife shows? They claim their blades are so strong and the edge so powerful yet when challenged to cut rope, they refuse to do so?
 
If it is the hanging rope cuts similar to what I have done my share of on competition, they are only practicing prudent caution. With so many of the population seeing this as some sort serious test of the knife alone, having an excellent blade in your hand while competing against aperson very skilled in rope cutting can only be bad P.R. for you even if your knife is superior. Cutting hanging rope is around 15% knife and about 85% cutting skill. I have botched cuts with knives that could shave frogs hair, and on better days effortlessly cut rope with things like a flat pry-bar (part of an Ashokan demonstration). I feel I make a decent knife, yet compared to some of the folks I have competed with I am a fairly lackluster rope cutter.

I got away from the cutting competitions for multiple reasons, not the least of which is that my chances of winning weren't all that good;), but another big reason was that it had drifted entirely away from testing the knife into more of a dog and pony show where a person with enough practice and a bit of luck could shine using almost anything for a blade.

If I got to choose who did the cutting with my knife and the other guys, heck yes! But if I have no control over the major determining factor for success, it is just a bad gamble and a really poor P.R. move.

It is funny I am taking time out to post this since right now I am working on stuff for the cutting demonstration at the ABS Mid-America event.
 
Kevin I've never thought about the cutting skill involved but now that you mention it cutting is an art. I had to show my soldiers how to use an axe in Afghanistan because they had never used one. They would spend all day cutting the same tree that I could take down in about 15 minutes with the same axe.

but about the paper. I don't know the answer to that but I do know that my mom could tell when we used her sewing scissors on paper.
 
Kevin: I don't mean hanging hemp rope. I mean hemp rope layed flat on a table and cut by pressing down.

I'm guessing that if you put a DULL knife into the worlds best hemp rope cutter, he is still not going to be able to cut the rope with it.

These knives I make are sharp as hell and the first time i attempted cutting free hanging rope, it only took one swipe to cut the rope at which was cut 3" inches from the bottom of the rope itself and not 2 feet or something crazy up from the bottom of the rope.
 
I hear that paper is one of the most abrasive things you could use on a knife. I'm guessing knives heat treated by the best heat treaters using stainless steel, that knife would dull after a few cuts as I have destroyed many edges on knives doing that. Who the heck knows!
 
GrayWall04 said:
Kevin I've never thought about the cutting skill involved but now that you mention it cutting is an art. I had to show my soldiers how to use an axe in Afghanistan because they had never used one. They would spend all day cutting the same tree that I could take down in about 15 minutes with the same axe.

but about the paper. I don't know the answer to that but I do know that my mom could tell when we used her sewing scissors on paper.
Click to expand...

Fabric scissors are a different beast altogether, I have some that are strictly for fabric and must stay that way as cutting anything else renders them rather useless on many types of fabric. This plays very heavily into the toothy edge vs. fine wedge situation. The way scissor edges engage each other with the material is entirely different than the average knife edge.

I divide all edges into two categories on the micro level, wedges and saws. Wedges do just that, they are fine and smooth enough to split materials apart when pushed straight into them, like straight razors and swords. Saws work by using a jagged interface to tear through material and work the best with drawing cuts, and are not quite as effective in straight line push cuts. Skinning knives would work good with this edge and the best macro example would be a bread knife, it really cuts when drawn through soft material but just sort of smashes the bread when used for push cuts.
 
not real sure what jute is, but maybe not? Hemp is like that brown stuff that falls apart when it's unravelled. like something you'd find holding a boat to the dock.

here's a photo of it

http://www.knotandrope.com/manilla.htm

Jute kinda looks like it but I don't know if it would be abrasive on knife edges or not...i'm sure someone can answer your question.
 
Man, I think tempering at 3 times after HT may have softened my blade! Definitely didn't pass the brass rod test!
 
anyone have advice better on tempering temperatures for A2 for first, second or even a third temper?
 
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