No, this isn't about shavehorses, let's be serious.
As I have been working on the manuscript for the book, I've been coming across all sorts of interesting things. I finally have the perfect excuse to jump down the rabbit hole on lots of topics and follow some long held assumptions to their logical end.
As I have been working through the sharpening details, I've found that I've been doing something wrong, or at least didn't know the right way, for years.
I've used diamond stones, paddles and hones for a long time. They are durable, cut fast and stay nice and flat. But I've never trusted them to finish the job, that is, remove the burr and leave a sharp edge.
What I recently learned is that I've been using them wrong.
Unlike waterstones, which have particles that break down in use and then serve to polish the edge to a higher degree, diamonds are more like sandpaper. Like sandpaper, diamonds can only take so much pressure before you are simply wasting pressure and scratching the surface up with the trapped shavings (called swarf). I found out long ago that a light touch is the key to sanding, letting the tiny edges take the cut that they were meant to and clearing the swarf often. Since I've applied the same idea to diamonds, my results are far beyond my expectations.
I don't know what it is about diamonds that made me want to bear down on them, perhaps it was the knowledge that they are so hard, or perhaps I just miss seeing the clear black marks that the steel makes on my waterstones that let's me know that they are working. Whatever it is, it took a leap of faith to use them lightly. As Greg Pennington says, use them like you are sharpening a feather.
I've been sharpening my drawknives with a new technique (teaser) that uses diamonds and the results are much improved. I still finish with a few strokes of the strop, but the burr is basically already gone.
See, admitting you are wrong isn't so hard...