Grit Effect on Rope Cutting Case 154CM

J

jeffbird

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Feb 3, 2011
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I put this in the traditional forum, but thought the effect of grit on rope cutting might be of general interest here.

I've been working with traditionals recently and experimenting with different edge finishes on my Case Bose Bullnose Trapper in 154CM. Will say, the edge retention on Case's 154CM was a pleasant surprise as my expectations were low going in.

Started off taking it up to 1200 grit on an Atoma diamond plate on an Edge Pro followed by a strop. It was hair popping sharp. It cut cardboard boxes fine.

Then tried cutting some 3/4" 100% Manila rope, which can be challenging to cut. Keep in mind that the area of 3/4" rope is 0.4418" vs. 0.1964" for 1/2" rope according to a quick online calculation, so more than double the amount of rope per cut compared to testing on 1/2" rope.

While the 1200 grit edge shaved hair easily, it would not cut the 3/4" Manila rope unless very heavy pressure was applied. After just a few cuts, it was apparent the finely finished edge was not working well. So, went back and used only the Atoma 140 followed by just a few passes on a horsehide strop to clean off the burr. What a difference. The edge still shaved arm hair, but importantly now also cut the 3/4" rope cleanly with 3 - 4 slices per piece. After 80 cuts on the rope, it still cleanly cut flimsy newsprint used in the advertisements, really flimsy stuff that shows any burrs or dull spots.

So, bottom line, Case's take on 154CM performs well with good edge retention, but does better with a "toothy" edge than a highly refined edge at least for this type of use.
This is my quick sharpening set up for testing the different finishes on this knife. It is a very simple setup and quick and easy. The Edge Pro suction cups stick best to the stove enamel, which is why it is on the stove. The 154CM took under ten passes per side with the Atoma 140 to produce a nice edge followed by just a few passes on the horsehide strop. Below is a quick and very rough video (Francis Ford Coppola is not losing his job to me lol 🤣) of the back porch testing this last edge with some newsprint cutting testing after 80 cuts on the 3/4" rope. Total time to sharpen and strop is under two minutes total. fwiw - I now use mineral oil on the Atoma plates as they were rusting after years of using water. So, now I only use mineral oil on these Atomas for the Edge Pro and also on my full size Atomas.

Hope this might be of interest and help to others.

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jeffbird said:
While the 1200 grit edge shaved hair easily, it would not cut the 3/4" Manila rope unless very heavy pressure was applied. After just a few cuts, it was apparent the finely finished edge was not working well. So, went back and used only the Atoma 140 followed by just a few passes on a horsehide strop to clean off the burr. What a difference. The edge still shaved arm hair, but importantly now also cut the 3/4" rope cleanly with 3 - 4 slices per piece. After 80 cuts on the rope, it still cleanly cut flimsy newsprint used in the advertisements, really flimsy stuff that shows any burrs or dull spots.
Click to expand...

So you were slicing rather than push-cutting? Did you try both?
 
Another Shepherd said:
So you were slicing rather than push-cutting? Did you try both?
Click to expand...

I tend to use pocket and hunting knives by pulling to make a cut, and doing so on the rope cutting most closely matches how I use the knife. Also, using a folder, especially one without any finger guard or lock, pulling mostly eliminates any risk of binding and fingers sliding onto the blade or causing it to snap closed. So that is my reasoning for making pull cuts.
 
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I've seen videos and had good luck with coarse on one side n fine on the other. I forget what grits the video suggested. I'll do it with venev diamond stones and finish one side with F400, the other with 1200. My 240 on one side doesn't do bad either. I think it's closer to his recommendations. I still take the knife to 1200 on both sides, and do a couple passes at a time switching sides and stones. I double the passes with the fine until the rough side scratch pattern looks good. He says to strop with a compound but I finish with a couple passes of the 1200 on both sides. For the last stages I only push the stone into the blade a couple passes at a time so no bur seems to ever form. Eliminates stopping right off the sharpener. The edge does really good n seems to come back easier with stropping.
 
I carried my dads old trapper and kept the clip blade very polished and finished the spey blade on a coarse India stone. No point finishing them the same when you have multiple blades.
 
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