Well, this begs the question " How do I handle straight razors with this knowledge?" If you put too much pressure on them, the edge will flex away from the strop... not enough and you won't polish out all the deeper scratches, so what to do? Should I just move the rod arms out 1 degree and then use more pressure?

I thought the 14m paste was supposed to leave 14m wide scratches in whatever it is abrading... so why are the 14m scratches so much smaller than the 7m scratches left by the diamond plate? Your's and Clay's expertise is much appreciated!!!

- Josh

Have I got a progression for you guys! I don't know that it proves or disproves anything, but it was a blast to do and will give us all a lot to talk about. Krystina Muller from Sharper than New sent in a Global boning knife that a customer of hers had sent in. It had originally been sent to Sur la Table for sharpening which was done on a Chef's Choice machine (I don't know the model.) Here are some before pictures, on by regular SLR and the other by microscope:







And for the finished product:



Next I'll start the progression images.

I decided to use the Chosera stones to remake the edge. My goal in doing so was to have as highly refined an edge as I could get (and my Shaptons are at home) because I wanted to take the edge to a super polish and then step backward with the strops so we could see the individual scratches from each grit really well. I set the angle at 15° per side and began sharpening the knife with the 400 grit Chosera, progressing through each grit all the way to the 10k Chosera. I didn't stop to photo each grit, waiting instead until I got all the way through. Here is the knife edge at 10k:

Next I wanted to see what the effect of plain leather would be so I used some horse butt strops, top grain out, moistened with distilled water:



I decided to look at split grain leather too, so I used a set of strops, also horse butt, but the split grain side:



Interesting...

Things got even more interesting at the next phase. I wanted to use a more gentle abrasive so I could get to the super polish more quickly, so I chose 1 micron boron carbide from Hand American for the next phase:



You can see the flattening of the ridges. The polish came up quickly and I had to put a polarizing filter on the scope.

You can see the effect that Tom so often describes displayed very well here: the deeper scratches are revealed as the bevel gets more polished. They've been hiding in all the refraction from the many surfaces of the previous grits.

Next I went to .5 micron chromium oxide, also from Hand American:



The polishing continues, ridges continuing to flatten out. We're getting closer to the valley floors.

In the previous two images, the immediate convex shaping of the edge is apparent. I didn't use very many strokes overall with each grit and yet the shape change was rapid. Note the little sedge or grass shaped scratch at the bottom of the bevel toward the right edge of the image - this little scratch stays with us for quite some time and serves as a useful reference point when comparing scratches. There are also two deep, parallel scratches in the middle that we can track.

Next up was the quarter micron diamond spray, also from Hand American:



I've been alternating stroke directions to make the new scratches easier to see.

Next came the .125 CBN spray from Ken at Precise Sharpening:



It gets confusing here, scratches running everywhere, don't seem to be making much improvement.