Why Rope?

[me2]

For those that test using only rope, why is this? Rope is something that is pretty specialized and not encountered by many people on a daily basis. Some makers test their blades only on rope, which tells me essentially zero about what their blades would do for me. Many here test on a variety of materials. Ankerson comes to mind, starting with cardboard, then moving to rope. I typically use cardboard, as its something my knives come into contact with pretty frequently. With the variety of steels out there now, I can only imagine that some steels excel at cutting specific media. For a knife that is intended as an overall performer, this might be a drawback.

 

[230grains]

Cardboard varies greatly. A box a pizza comes in is going to wear your edge differently than a box a giant refrigerator comes in. Rope differs as well, but hemp rope for the most part is going to cut the same as long as the thickness is the same. That said, if you have the same cardboard over and over, it's obviously going to be more accurate.

 

[knarfeng]

I use manila robe because:

• Rope is more uniform than cardboard. Not only are there various grades of cardboard, but cardboard itself is not terribly uniform. So cutting tests based on rope are more repeatable.
• Rope does not bind as much, so the blade shape does not contribute as much toward the observed results. Anything that lowers the number of variables in an experimental setup is goodness.

I actually got the idea of using manila rope from Phil Wilson, but once I considered it, I adopted it wholeheartedly.

 

[Jason B.]

Manila rope causes very even wear on the edge and doesn't wear away the edge too quickly. This makes it easier to see the stages of edge loss (retention) clearly. It makes distinguishing slight differences between steels much easier than other test media IMO.

 

[Ankerson]

Rope is very consistent, is very abrasive on the edges. but is slow enough that I can see the different stages of edge wear and the results are repeatable.

I use 3 types of media, Manila rope, cardboard and wood:

Rope is the most important and the 1st stage for me because it will help me see what is going on with the steel and the edge and most of the time some kind of edge failure and or serious wear with turn up in this stage.

Cardboard is the 2nd stage, can be even more abrasive and hard on the edges depending on the cardboard, and most of the damage to the edges could show up in this stage.

Wood is the 3rd stage and more aggressive in that I push the edges pretty hard in this stage to see how sturdy they are.

 

[me2]

And that's the kind of thing I'm talking about. Different things are used because just using rope doesn't give the whole picture.

 

[Noctis3880]

And that's the kind of thing I'm talking about. Different things are used because just using rope doesn't give the whole picture.

That, and different edge finishes are good for different tasks. I suspect a polished edge would work better on cardboard than rope, and a toothy edge would be needed to "bite" into the rope rather than just slide off.

 

[knarfeng]

And that's the kind of thing I'm talking about. Different things are used because just using rope doesn't give the whole picture.

If you are just evaluating the alloy, all you need is a consistent wearing medium.
If you are evaluating the performance of the entire blade, you need more.

 

[me2]

So you don't think there is a case to be made for different steels reacting differently to various wearing media?

 

[RKH]

I began using Manila rope after reading an article by Wayne Goddard on sharpening. That is where I learned about Norton Crystolon and India fine stones for sharpening. This was around 1989 and about the same time I read some articles by Steven Dick on testing and sharpening knives and he used the same thing. Many of my knives would just slide over the rope and not cut it. i think it is one of many types of materials that help to determine sharpness. BTW, if you think your knife is sharp try slicing Cigarette rolling papers.

RKH

 

[knarfeng]

So you don't think there is a case to be made for different steels reacting differently to various wearing media?

I don't think there is a case for the steel itself reacting differently to different media. I don't know this as a fact, but that is my opinion.

I do think there is a case for how a highly polished edge reacts vs. a coarser edge, even when they are the same alloy and at the same angle.

 

[Ankerson]

I don't think there is a case for the steel itself reacting differently to different media. I don't know this as a fact, but that is my opinion.

I do think there is a case for how a highly polished edge reacts vs. a coarser edge, even when they are the same alloy and at the same angle.

Steels will react differently depending on the media used and some steels will just work better on certain types of media than others even with the same edge and profile.

That would have to do the the Alloy Content and size of the carbides of the different steels, some will cut more aggressively than others on certian types of media, I have seen this 1st hand more than a few times.

That's why I have been working and testing lately on the optimal edge finish for overall use and have found the 600 Grit EP stone and now the Congress MOLDMASTER 400 Grit Sil Carbide stone give the best overall edge for both cutting efficiency and edge holding over anything else I have tried.

 

[knarfeng]

I haven't.

Edited to add:
Let me clarify. I have noticed that different knives of the same alloy. the same edge angle, and the same hardness feel differently when cutting different materials. I have noticed the same between knives of different alloys with the same alloy and same edge angle. If knives of the same alloy can behave differently, why would I not expect different alloys to behave differently?

 

[BITEME]

Although rope gets mentioned a lot around here I have also seen that the guys use a bunch of different media for example one of the guys was cutting into large empty cans of olive oil and sneaker soles,and if that isn't enough he was using zdp-189, btw it held up great!!. Personally I am always cutting electrical tape and food grade 3/8" tubing and 1/4" nylon rope believe it or not after a few days of this I have to re-touch my s30v para2 ,but usu. only a few strokes on the ceramic and it's ready,technically I could probably keep going w/the same untouched edge for a while but I don't to take the knife home every few days to resharpen on my other stuff.

 

[Ankerson]

I haven't.

Edited to add:
Let me clarify. I have noticed that different knives of the same alloy. the same edge angle, and the same hardness feel differently when cutting different materials. I have noticed the same between knives of different alloys with the same alloy and same edge angle. If knives of the same alloy can behave differently, why would I not expect different alloys to behave differently?

I have noticed the same model knives sharpened exactly the same way, but in different steels react differently to the same types of media.

 

[me2]

I guess where I'm ultimately headed with this is I think only testing on rope could be misleading, based on different alloys reacting differently with different media. If every knife in every alloy only gets tested on rope, and a "best" alloy is determined from this, then the "best" could fall quickly if the media changes to cardboard or wood. Of course there are many other variables, lately degree of polish seems popular. Ultimately, this leads to the need to state test media, angle, edge finish, etc. and opens the possibility that an "inferior" steel can out cut a "better" one with (im)proper selection of the different variables. Many who have been around a while already know this, based on Buck's testing and selection of a thinner edge angle on their standard steel.

 

[Ankerson]

I guess where I'm ultimately headed with this is I think only testing on rope could be misleading, based on different alloys reacting differently with different media. If every knife in every alloy only gets tested on rope, and a "best" alloy is determined from this, then the "best" could fall quickly if the media changes to cardboard or wood. Of course there are many other variables, lately degree of polish seems popular. Ultimately, this leads to the need to state test media, angle, edge finish, etc. and opens the possibility that an "inferior" steel can out cut a "better" one with (im)proper selection of the different variables. Many who have been around a while already know this, based on Buck's testing and selection of a thinner edge angle on their standard steel.

There are a lot a variables involved, but rope is a good test medium because if the steel and edge is efficient at that then it will likely cut most other things very well also.

Manila rope isn't really that easy to cut.

 

[db]

Steels will react differently depending on the media used and some steels will just work better on certain types of media than others even with the same edge and profile.

That would have to do the the Alloy Content and size of the carbides of the different steels, some will cut more aggressively than others on certian types of media, I have seen this 1st hand more than a few times.

That's why I have been working and testing lately on the optimal edge finish for overall use and have found the 600 Grit EP stone and now the Congress MOLDMASTER 400 Grit Sil Carbide stone give the best overall edge for both cutting efficiency and edge holding over anything else I have tried.

Now this is refreshing to see. I have thought for a very long time that this is true. I use a Spyderco medium bench hone to get the finish I like. I keep reading all the time on the forums that the most polished edge is the sharpest most long lasting edge over all others. I just never can agree with that. Every now and again after reading so many posts about that perfect polished edge I'll polish one up again just to remind myself that my current edge really does work the very best for my style of knife use. In fact I just polished one up this week and have been carrying and useing it. I'll bee returning to my Spyderco bench hone soon. I really don't agree that carbide size makes very much difference as your sharpening hone should be able to cut them. I think the difference people notice is grain size and yes the two are related but the heat treatment and other factors effect this difference as well. Basicly I think judging by carbides isn't a very fair or good idea. Just look at all the different ways D2 acts depending on who's D2 your useing.

 

[Ankerson]

Now this is refreshing to see. I have thought for a very long time that this is true. I use a Spyderco medium bench hone to get the finish I like. I keep reading all the time on the forums that the most polished edge is the sharpest most long lasting edge over all others. I just never can agree with that. Every now and again after reading so many posts about that perfect polished edge I'll polish one up again just to remind myself that my current edge really does work the very best for my style of knife use. In fact I just polished one up this week and have been carrying and useing it. I'll bee returning to my Spyderco bench hone soon. I really don't agree that carbide size makes very much difference as your sharpening hone should be able to cut them. I think the difference people notice is grain size and yes the two are related but the heat treatment and other factors effect this difference as well. Basicly I think judging by carbides isn't a very fair or good idea. Just look at all the different ways D2 acts depending on who's D2 your useing.

There is a balance there in the amount of refinement that can make the difference.

Basically I would say that a semi polished edge would be the best balance from my testing depending on the final micron rating and the steel so it would be someplace in the middle.

In cutting rope I have seen as much as a 8 LB swing in cutting pressure in different edge finishes.....

 

[Phil Wilson]

Hi, Me 2
I see your point that only cutting rope does not give the total picture. That is true to some extent but I would ask if you don’t use rope for testing what would you use? With a good blade I can cut cardboard until I get tired and the blade gets hot. It will wear the blade but most of the time just gunks it up. The idea at least in my mind is to use a medium that would give a good estimate of how the blade is going to work in the real world. I make utility-hunting-and fishing knives (fillet) and some kitchen knives. Rope is the very best I have found to predict how a knife is going to work field dressing, skinning a deer or elk. Manila rope fibers are a lot like elk hair or pig bristles. It also is pretty good for checking the performance of a fillet knife. Cutting fish bones, scales ect. is not as much of a wear challenge but some predictions can be made. A rough correlation is ---- if a knife will do 150 slicing cuts on ¾ rope without losing the bite then it will be capable of skinning an elk without re-sharpening. A fillet knife that will do the same will usually lose the edge from corrosion effects before it gets dull filleting a box full of bottom fish. By the way I have found that you have to use at least 5/8 rope to challenge the edge on a good blade. I have a BUC , K294 blade at RC 64 that will do over 300 cuts on ¾ starting at at 12 lbs and finishing at 20lbs on a UPS calibrated scale. After that it would still slice newsprint and skive leather. I can only guess how many cuts would be reqd. on ½ rope to get the same amount of wear.
Other than checking the cutting efficiency of a blade, cutting rope will also tell you a lot about economics of the total knife. 300 or so cuts on ¾ rope will find the hard edges and hot spots on a handle pretty quick. There has been some discussion about course verses polished edges recently on this forum. Cutting rope will tell you what the best edge for that application is very quickly. An edge that will slice through rope, not slide will be an edge that will cut most anything in the real world that I can think off. Exceptions would be shaving and surgery. Cutting rope will teach you a lot about sharpening. In the end rope cutting will tell the story about the knife. If blades are the same shape, grind, sharpening , hardness, heat treating, then you can make some predictions about steel. Large differences will show up but small differences will be lost in testing technique and error. There are problems with consistency from batch to batch, humidity makes a difference, and rope can have various amounts of dirt, but yes, I only cut rope for checking “cutting efficiency” of a knife. I whittle seasoned fir to check for edge rolling or chipping, but overall I would vote for rope as the best test media and it is pretty much all I use now. Phil