So I did a little bit of cardboard cutting with my Kulgera yesterday to see how it would effect the edge from beginning to end and in between. I used a RazorEdge Systems EdgeTester, a 30X illuminated loupe and my chin hairs to observe effect on the edge, which was ground in at 30* inclusive on a 1K Norton benchstone and then stropped for about 800 passes on plain leather. I also used arm-hair shaving and phonebook paper slicing as an indicator of sharpness, as well as "hair whittling"--though I'll use that term for lack of a better one. At the start of the test it could easily cut phonebook paper and carve hair--though not necessarily hair whittling since the hair needed to be held taught--and could easily shave arm hair.
Anyway, I had four pieces of cardboard that were about 8" x 18". I cut ~1" wide strips length-wise out of the cardboard going against the corrugations, using a slicing motion starting from the butt of the knife to the tip, then I would alternate and do a push-cut at the mid-way point, the butt and the tip of the knife to test all the portions of the blade geometry.
Starting out the edge had a couple of deformities about 3" away from the butt of the knife visible only as glints in the 30X loupe, but easily detectable by the EdgeTester; otherwise the crest of the edge was smooth and black. The first cardboard sheet I was able to get six cuts out of, and then observed the edge again. The butt portion of the knife developed a couple of edge deformations both visible and detectable with the EdgeTester, and the portion of the knife with the "swedge" near the tip had detectable deformations with the EdgeTester, but not visible ones.
I continued and finished with the second sheet of cardboard with no perceivable difference in cutting ability, but several more deformities became detectable across the mid-portion of the blade, and now the edge looked very "toothy" instead of very smooth under the illumination of the LED. There were many glints and specs of light, and the edge itself was shining white rather than there just being a smooth edge that was black like when I started. I'm not sure if there was a bit of micro-chipping happening or if it was the effect of S30V becoming "toothier", but at this point I would say that the edge was essentially covered with micro deformities--only visible as glints of light under illuminated magnification, but still there nonetheless. They were highly detectable with the EdgeTester.
About halfway through the third sheet I started having some difficulty with the slicing cuts not making as far into the cardboard as they had at first, but the push cuts were still fairly easy. However it was at this point that I noticed the corrugated portions of the cardboard on the inside were being deformed slightly before being cut, and the ends were starting to have a very unclean "mashed" effect to them. This is in contrast to very cleanly cut, undeformed corrugations during the first sheet's cutting.
All in all I completed 69 cuts through 18" of cardboard, alternating between push-cutting at different portions of the blade. The knife continued to cut phonebook paper throughout the entire test, but at the very end the deformities toward the front of the knife worsened and began catching bits of cardboard as well as phonebook paper. The knife remained sharp enough to shave armhair the entire time as well as carve hair, but at one point a portion near the butt did fail the EdgeTester so I think it may have rolled over.
It wasn't a very extensive test at all, but I wanted to see what kind of damage S30V would take in a task like someone sitting down for an afternoon to break up cardboard, and I had some boxes laying around from the move. Given the length of the cuts I think that 69 is a fairly high number. I got about 6-8 cuts per sheet, depending on how close to an inch my strips were, so I would estimate that in total anywhere between 432 and 576 inches of cardboard were cut between 4 sheets, and the edge was still very sharp at the end of it, though the difference in its cutting ability was noticeable and there was plenty of visible damage under 30X magnification, and even more to find using an EdgeTester. After stropping for about 50 passes on plain leather, many of the deformities are still visible, but are much smaller and the edge itself went from the white shining indicator that it was becoming dull back to the black, barely visible crest. They do not seem to have a terrible effect on performance as it still slices phonebook paper great, but there is definitely many more of them than the one or two I saw near the tip to begin with.
Anyway, I just wanted to see how it would handle and thought I might be able to do it a bit methodically to see if anyone can manage to get some useful data out of it. The edge was nowhere near dull when I stopped, but there was some definite wear. All in all though, considering that I could still shave arm hair, carve taught facial hair and slice up phonebook paper I would say that there was no significant wear for the amount of cardboard that was cut past some slight edge deformations only visible at 30X magnification--some of which that barely even visible then. So anyway, I hope someone gleamed something insightful from all of this.
I still have a lot of boxes left over from the move, so I can do more testing if someone has some suggestions. Always helps to get more data out there, and I'm sure no one wants to go down to U-Haul just to get boxes to cut up. These are the knives I have available to test: A Case Trapper in CV, a Kershaw Needs Work in 14C28N, and a Buck 119 in 420HC. I also have a nice Scrade stockman in 440 that I reground to a convex edge. Oh, and of course the Kulgera in S30V. My collection is kind of modest.
Anyway, I had four pieces of cardboard that were about 8" x 18". I cut ~1" wide strips length-wise out of the cardboard going against the corrugations, using a slicing motion starting from the butt of the knife to the tip, then I would alternate and do a push-cut at the mid-way point, the butt and the tip of the knife to test all the portions of the blade geometry.
Starting out the edge had a couple of deformities about 3" away from the butt of the knife visible only as glints in the 30X loupe, but easily detectable by the EdgeTester; otherwise the crest of the edge was smooth and black. The first cardboard sheet I was able to get six cuts out of, and then observed the edge again. The butt portion of the knife developed a couple of edge deformations both visible and detectable with the EdgeTester, and the portion of the knife with the "swedge" near the tip had detectable deformations with the EdgeTester, but not visible ones.
I continued and finished with the second sheet of cardboard with no perceivable difference in cutting ability, but several more deformities became detectable across the mid-portion of the blade, and now the edge looked very "toothy" instead of very smooth under the illumination of the LED. There were many glints and specs of light, and the edge itself was shining white rather than there just being a smooth edge that was black like when I started. I'm not sure if there was a bit of micro-chipping happening or if it was the effect of S30V becoming "toothier", but at this point I would say that the edge was essentially covered with micro deformities--only visible as glints of light under illuminated magnification, but still there nonetheless. They were highly detectable with the EdgeTester.
About halfway through the third sheet I started having some difficulty with the slicing cuts not making as far into the cardboard as they had at first, but the push cuts were still fairly easy. However it was at this point that I noticed the corrugated portions of the cardboard on the inside were being deformed slightly before being cut, and the ends were starting to have a very unclean "mashed" effect to them. This is in contrast to very cleanly cut, undeformed corrugations during the first sheet's cutting.
All in all I completed 69 cuts through 18" of cardboard, alternating between push-cutting at different portions of the blade. The knife continued to cut phonebook paper throughout the entire test, but at the very end the deformities toward the front of the knife worsened and began catching bits of cardboard as well as phonebook paper. The knife remained sharp enough to shave armhair the entire time as well as carve hair, but at one point a portion near the butt did fail the EdgeTester so I think it may have rolled over.
It wasn't a very extensive test at all, but I wanted to see what kind of damage S30V would take in a task like someone sitting down for an afternoon to break up cardboard, and I had some boxes laying around from the move. Given the length of the cuts I think that 69 is a fairly high number. I got about 6-8 cuts per sheet, depending on how close to an inch my strips were, so I would estimate that in total anywhere between 432 and 576 inches of cardboard were cut between 4 sheets, and the edge was still very sharp at the end of it, though the difference in its cutting ability was noticeable and there was plenty of visible damage under 30X magnification, and even more to find using an EdgeTester. After stropping for about 50 passes on plain leather, many of the deformities are still visible, but are much smaller and the edge itself went from the white shining indicator that it was becoming dull back to the black, barely visible crest. They do not seem to have a terrible effect on performance as it still slices phonebook paper great, but there is definitely many more of them than the one or two I saw near the tip to begin with.
Anyway, I just wanted to see how it would handle and thought I might be able to do it a bit methodically to see if anyone can manage to get some useful data out of it. The edge was nowhere near dull when I stopped, but there was some definite wear. All in all though, considering that I could still shave arm hair, carve taught facial hair and slice up phonebook paper I would say that there was no significant wear for the amount of cardboard that was cut past some slight edge deformations only visible at 30X magnification--some of which that barely even visible then. So anyway, I hope someone gleamed something insightful from all of this.
I still have a lot of boxes left over from the move, so I can do more testing if someone has some suggestions. Always helps to get more data out there, and I'm sure no one wants to go down to U-Haul just to get boxes to cut up. These are the knives I have available to test: A Case Trapper in CV, a Kershaw Needs Work in 14C28N, and a Buck 119 in 420HC. I also have a nice Scrade stockman in 440 that I reground to a convex edge. Oh, and of course the Kulgera in S30V. My collection is kind of modest.
