I was curious about two things. The first was the difference in sharpness I'd obtain working with an extra course and fine diamond stone. The second is feeling for the push cutting and slicing ability of the two different edges.
To measure sharpness I am push cutting light cotton thread on a postal scale. The numbers listed below represent the grams of force required to make the cut. All 10 attempts are done in the same half inch portion of edge.
1. I cut the edge off my mule 52100 by dragging the edge perpendicular to the stone.
2. Reprofiled the edge to ~10 degrees per side.
3. Put an edge on the knife using the same stone I reprofiled on, a DMT extra course stone, using very light and very few strokes at a slightly more obtuse angle. Surprisingly easy to get a hair popping sharp edge off the extra course stone.
Sharpness test:
1. 73.8
2. 78.3
3. 140
4. 80
5. 75.4
6. 72.5
7. 78.1
8. 44.4
9. 77.1
10. 51.5
Average - 77.11
3. Cut the edge off, then ground the microbevel out using the 10 degree angle again.
4. Edged the knife with a DMT fine stone using the same microbevel technique. Edge easily whittled hair.
Sharpness test:
1. 44
2. 54.3
3. 29.7
4. 53
5. 39.4
6. 50.1
7. 51.8
8. 53.2
9. 46.1
10. 38.7
Average - 46.03
After each sharpness testing I push cut and sliced cardboard to see how much of a difference the different edges would have in the same material using each type of cut.
With the course edge it sliced well, did not start a push cut well but once it got going it cut alright. After cutting up about 10 feet of cardboard the edge had no difficulty shaving.
With the fine edge it push cut better, especially starting the cut. The effort to start the cut was greatly reduced, while effort expended in the middle of the cut was only a little ahead of the previous edge. During slicing the knife did just as good from what I could tell. I even cut twice the amount of cardboard to compensate for the higher sharpness rating, and towards the end it still sliced the cardboard easily. I cut another 10 feet just to be sure and while the edge was dragging more than at the beginning slicing ability was still strong.
In the future I think I'll repeat the tests on other materials, like vegetation, raw meat, rope and so forth. The test did appear to conform to a few things I had previously observed:
-That coarse edges are not leagues ahead of more polished edges in slicing
-Shaving sharpness is easily obtainable using lower grit stones, that it's not an ability restricted to polished edges.
-Hair whittling sharpness is worth it (Started the cut much more easily, only spent a minute tops forming the edge too)
To measure sharpness I am push cutting light cotton thread on a postal scale. The numbers listed below represent the grams of force required to make the cut. All 10 attempts are done in the same half inch portion of edge.
1. I cut the edge off my mule 52100 by dragging the edge perpendicular to the stone.
2. Reprofiled the edge to ~10 degrees per side.
3. Put an edge on the knife using the same stone I reprofiled on, a DMT extra course stone, using very light and very few strokes at a slightly more obtuse angle. Surprisingly easy to get a hair popping sharp edge off the extra course stone.
Sharpness test:
1. 73.8
2. 78.3
3. 140
4. 80
5. 75.4
6. 72.5
7. 78.1
8. 44.4
9. 77.1
10. 51.5
Average - 77.11
3. Cut the edge off, then ground the microbevel out using the 10 degree angle again.
4. Edged the knife with a DMT fine stone using the same microbevel technique. Edge easily whittled hair.
Sharpness test:
1. 44
2. 54.3
3. 29.7
4. 53
5. 39.4
6. 50.1
7. 51.8
8. 53.2
9. 46.1
10. 38.7
Average - 46.03
After each sharpness testing I push cut and sliced cardboard to see how much of a difference the different edges would have in the same material using each type of cut.
With the course edge it sliced well, did not start a push cut well but once it got going it cut alright. After cutting up about 10 feet of cardboard the edge had no difficulty shaving.
With the fine edge it push cut better, especially starting the cut. The effort to start the cut was greatly reduced, while effort expended in the middle of the cut was only a little ahead of the previous edge. During slicing the knife did just as good from what I could tell. I even cut twice the amount of cardboard to compensate for the higher sharpness rating, and towards the end it still sliced the cardboard easily. I cut another 10 feet just to be sure and while the edge was dragging more than at the beginning slicing ability was still strong.
In the future I think I'll repeat the tests on other materials, like vegetation, raw meat, rope and so forth. The test did appear to conform to a few things I had previously observed:
-That coarse edges are not leagues ahead of more polished edges in slicing
-Shaving sharpness is easily obtainable using lower grit stones, that it's not an ability restricted to polished edges.
-Hair whittling sharpness is worth it (Started the cut much more easily, only spent a minute tops forming the edge too)
Last edited:
