I’ve been doing some more fun stuff with the machine today. I’m setting up to do a side by side comparison of two blades, both taken to the 10k Chosera stones then stropped down to .125um CBN on kangaroo, one at the same sharpening angle of 15° and the other stropped at 13°. I won’t spoil the results yet as to which is sharper more durable, that will have to wait until tomorrow. In the meantime, I can share how the edge of the one stropped at 13° fared over 40 repetitions of the test. The chart below shows the grams of force required to rupture the tape at each repetition:
With each repetition I’m applying force to the exact same spot on the blade. There are some peaks and valleys within the overall upward trend of force required. The higher the number, the duller the blade is getting. I suspect the very edge is deforming under the load and occasionally it deforms to a shape that momentarily improves its sharpness and that is what we are seeing in the valleys. Other explanations for the valleys could be weak spots in the tape or imperfections in the collar holding the tape. If it is imperfections in the collar that we’re seeing, we’ll probably be able see corresponding valleys in subsequent series which would represent the locations on the collar that are different from the norm.
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