07-02-2018, 12:35 PM
That's good stuff Cyrano and an excellent tutorial! All of your edge measurements before and after burr removal seem very much in-line to us and track with your photographs as well. We haven't spent a ton of time measuring edges before any attempts have been made at removing the burr but we think that your measurements fall very much within the expected zone. Dependent on the grinding circumstances, we've seen 350 and we've seen 700. Of course, we're not attempting to accurately measure the sharpness level of a burr edge. First and foremost, we're simply trying to detect the presence of a burr. The point is that neither number, 350 or 700, is acceptable for most skilled sharpeners and that burr removal activities need to commence.
We think that your last two pictures point out the advantage of using an edge tester in conjunction with a microscope. We know that if 50% of the edge contains residual burr and if 50% doesn't that there must be a 50/50 chance of getting a good/bad reading with any of our edge tester models. This information may be gleaned with an edge tester alone by taking multiple measurements but the way that you did it, utilizing a microscope, seems much more efficient and informational. So much so that this is the way that we do it.
So here is our takeaway from your experiment; you are well on your way to having established a well documented sharpening process. Using the same knife, and under the same set of grinding parameters, a double session on the leather wheel should yield the edge seen in your last picture. If you repeat the experiment with similar results then you might be able to chisel this one in stone.
One last comment here and not on your sharpening efforts but on ours. Those little blobs of burr remaining after your first burr removal effort sent chills up our spines. Fortunately, it appears that all of yours were removed with just an additional session with the leather wheel. With our past sharpening efforts, we've seen them where they couldn't be removed with a stick of dynamite. In our case, the problem turned out to be too much grinding pressure during the last couple of passes. Our's were just too gnarly and robust to stand back up so that they could be removed.
This was a great post so thank you.
We think that your last two pictures point out the advantage of using an edge tester in conjunction with a microscope. We know that if 50% of the edge contains residual burr and if 50% doesn't that there must be a 50/50 chance of getting a good/bad reading with any of our edge tester models. This information may be gleaned with an edge tester alone by taking multiple measurements but the way that you did it, utilizing a microscope, seems much more efficient and informational. So much so that this is the way that we do it.
So here is our takeaway from your experiment; you are well on your way to having established a well documented sharpening process. Using the same knife, and under the same set of grinding parameters, a double session on the leather wheel should yield the edge seen in your last picture. If you repeat the experiment with similar results then you might be able to chisel this one in stone.
One last comment here and not on your sharpening efforts but on ours. Those little blobs of burr remaining after your first burr removal effort sent chills up our spines. Fortunately, it appears that all of yours were removed with just an additional session with the leather wheel. With our past sharpening efforts, we've seen them where they couldn't be removed with a stick of dynamite. In our case, the problem turned out to be too much grinding pressure during the last couple of passes. Our's were just too gnarly and robust to stand back up so that they could be removed.
This was a great post so thank you.